Project-ZIC/Rita.html at main · omwtbarca/Project-ZIC · GitHub

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Challenges and Improvement Strategies Progress of Lithium Metal Anode[J]. <em>Acta Physico-Chimica Sinica</em>, 2021, 37(1): 2006021-0. doi: <a href=\"http://dx.doi.org/10.3866/PKU.WHXB202006021\">10.3866/PKU.WHXB202006021</a>","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[28,29]},"content":"keywords:","children":[{"type":"list_item","depth":3,"payload":{"lines":[29,30]},"content":"体积膨胀-三维材料 硬度/稳定性、骨架","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[30,31]},"content":"亲锂性改善：与锂形成合金化合物的材料一般能够降低锂成核过电势和诱导锂成核。","children":[{"type":"list_item","depth":4,"payload":{"lines":[31,32],"index":1},"content":"1. 掺杂：通过向材料中引入适当的掺杂元素，可以调节其电子结构和晶格结构，从而改善其亲锂性能。掺杂改善了材料的导电性和离子扩散性，提高了锂离子的嵌入和脱嵌效率。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[32,33],"index":2},"content":"2. 表面修饰：对材料的表面进行修饰可以改变其表面化学性质和结构，从而增强其与锂离子的相互作用。一种常见的表面修饰方法是涂覆一层纳米材料，如金属氧化物、导电聚合物等。例如，使用导电聚合物（如聚咔唑）修饰的碳材料可以提高其亲锂性能。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[33,34],"index":3},"content":"3. 纳米结构设计：通过精确控制材料的纳米结构，如纳米颗粒、纳米线或纳米片等，可以增加其表面积和锂离子扩散路径，提高材料的亲锂性能。例如，二维材料石墨烯可以通过形成纳米片或纳米管的结构来增强其对锂离子的吸附能力。<mark>nanobrush</mark>","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[34,35],"index":4},"content":"4. 合金化：F4c: LiAl合金。通过将材料与其他金属或化合物形成合金化结构，可以调节其电子结构和晶格结构，从而改善其亲锂性能。例如，硅合金作为锂离子电池负极材料，通过与锡等金属形成合金，可以显著提高其亲锂性能。","children":[]}]},{"type":"list_item","depth":3,"payload":{"lines":[36,37]},"content":"对于金属集流体的主要设计策略集中于两方面，一是设计多孔结构提高表面电化学活性面积提高储锂的空间，二是合金层或亲锂性化合物修饰金属基体，起到诱导锂成核生长和均匀化锂离子流的作用。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[37,38]},"content":"<mark>粉体材料相对于三维自支撑骨架的优点主要在于其大面积合成制备工艺更加简单从而可以规模化制备复合锂金属负极。</mark>","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[38,39]},"content":"粉体的多孔性和亲锂性质是其材料结构中的重要因素，并且可以通过设计合理的材料成分和结构来构建高离子扩散/电子传输动力学锂负极。三维基体在解决了锂无限膨胀等问题的同时也仍然面临着一些问题，如<mark>其多孔和纳米结构增加了副反应，骨架基体一定程度上降低了锂的比容量等</mark>。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[40,41]},"content":"保护锂负极的电解液优化策略:","children":[{"type":"list_item","depth":4,"payload":{"lines":[41,42]},"content":"提高锂盐浓度，","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[42,43]},"content":"稳定SEI","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[43,44]},"content":"诱导锂沉积的添加剂策略。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[46,47]},"content":"background","children":[{"type":"blockquote","depth":3,"payload":{"lines":[49,50]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[49,50]},"content":"锂金属由于其高比容量和低电极电势等优点被认为是下一代高比能量电池体系中最有潜力的负极材料。然而由于锂金属的高活性，锂负极在循环过程中会产生大量的枝晶，导致SEI (solid-electrolyte interphase)破裂，并且枝晶增加了电极与电解液的接触面积，使得副反应进一步增加。此外，脱落的枝晶形成死锂，从而降低电池的充放电库仑效率。并且不可控的锂枝晶持续生长会刺穿隔膜引发电池短路，伴随着电池热失控等安全问题。","children":[]}]},{"type":"blockquote","depth":3,"payload":{"lines":[57,58]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[57,58]},"content":"传统石墨负极材料较低的理论比容量(372 mAh·g-1)以及较高的电压平台，造成传统锂离子电池无法进一步突破其比能量瓶颈(260 Wh·kg-1) <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b5\">5</a>。探索具有高理论比容量和低电极电势的负极材料，在电池材料体系上使电池达到更高的比能量<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b6\">6</a>, <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b7\">7</a>。锂金属具有高理论比容量(3860 mAh·g-1)和低电极电势(-3.04 V <em>vs</em> SHE (standard hydrogen electrode))等特点。","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[69,81]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[69,70]},"content":"1️⃣ 死锂","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[71,72]},"content":"2️⃣ 体积扩张---三维材料:<mark>较高的力学强度和稳定性，适用于结构材料、金属合金等领域</mark>","children":[{"type":"list_item","depth":5,"payload":{"lines":[73,74]},"content":"锂金属的无限体积膨胀也会导致其锂电极粉化、电解液消耗、大量产气等各种问题","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[74,75]},"content":"由于其无基体转化反应的特性而存在无限体积膨胀的问题","children":[{"type":"list_item","depth":6,"payload":{"lines":[75,76]},"content":"设计多种三维导电骨架用于预储锂基体，三维导电骨架不仅可以限制锂的无限体积膨胀而且能够均匀化锂离子流，降低表面有效电流密度，从而抑制锂枝晶的生长。","children":[]}]}]},{"type":"list_item","depth":4,"payload":{"lines":[77,78]},"content":"3️⃣ 锂枝晶","children":[{"type":"list_item","depth":5,"payload":{"lines":[79,80]},"content":"<mark>在电池多次充放电后，锂金属表面会不断生长出锂枝晶，大量枝晶对隔膜具有较大的应力导致隔膜被刺穿，从而引发电池短路、着火、产气爆炸等热失控问题</mark>","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[80,81]},"content":"电解液及添加剂改善锂金属负极----&gt; 有效地改变锂金属表面SEI的成分和调节锂离子的沉积行为从而抑制锂枝晶的生长","children":[]}]}]}]},{"type":"heading","depth":2,"payload":{"lines":[84,85]},"content":"局限性：","children":[{"type":"list_item","depth":3,"payload":{"lines":[89,90],"index":1},"content":"1. 锂的无限体积膨胀；锂金属不同于石墨，硅等嵌入型或合金类负极，它是一种无基体转化型负极，石墨和硅的体积膨胀分别是10% <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b22\">22</a>和400% <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b23\">23</a>，而锂负极的体积膨胀是无限的，导致沉积锂的形貌结构呈现多孔疏松的状态。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[91,92],"index":2},"content":"2. 死锂的产生；锂的无限体积膨胀和枝晶均会造成锂表面结构多孔疏松，经过多次充放电循环后，表面不稳定的锂会逐渐粉化并脱落下来从而失去电活性，从而产生大量死锂。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[93,94],"index":3},"content":"3. SEI破裂和副反应增加；锂枝晶的生长和死锂的产生会导致锂表面SEI破裂和重构，不断的重构SEI需要消耗额外的电解液，造成副反应增加。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[95,96],"index":4},"content":"4. 极化电压增大；锂枝晶和死锂导致锂金属表面多孔疏松，SEI的比表面积和厚度均会随之增大，从而使Li+的扩散路径增加，并且死锂会导致表面阻抗增加，这些因素都会造成锂金属电池在多次循环后的极化电压显著增加。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[97,98],"index":5},"content":"5. 电池短路；锂枝晶的不断生长会造成其对隔膜的应力增加，最终会刺穿隔膜导致电池短路，从而引发电池热失控等安全问题。综上所看，锂金属的挑战众多，需要不断的探索新的策略以解决其存在的诸多问题。","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[99,100]},"content":"枝晶成核生长模型","children":[{"type":"fence","depth":3,"content":"<pre><code class=\"language-mermaid\">\ngraph TD\n\n  subgraph 枝晶成核生长模型\n\n   b{{&quot;1️⃣&quot;表面成核生长模型}}--&gt;  d{{&quot;2️⃣&quot;电荷诱导生长模型}}--&gt;  f{{&quot;3️⃣&quot;SEI扩散控制模型}}--&gt;  c{{&quot;4️⃣&quot;沉积-溶解模型}}\n\n\n   end\n\n</code></pre>\n","children":[],"payload":{"lines":[107,119]}},{"type":"heading","depth":3,"payload":{"lines":[123,124]},"content":"1.表面成核生长模型","children":[]},{"type":"heading","depth":3,"payload":{"lines":[127,128]},"content":"2.电荷诱导生长模型","children":[]},{"type":"heading","depth":3,"payload":{"lines":[133,134]},"content":"3. SEI扩散控制模型","children":[{"type":"list_item","depth":4,"payload":{"lines":[137,138]},"content":"初始锂盐浓度越低，表面有效电流密度越大，越容易产生锂枝晶。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[139,140]},"content":"SEI作为锂负极表面重要的组成部分，影响着阳离子迁移数，即控制着过渡时间，并且不稳定SEI会加剧锂离子消耗，促使表面微区<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi>L</mi><msup><mi>i</mi><mo>+</mo></msup></mrow><annotation encoding=\"application/x-tex\">Li^+</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.7713em;\"></span><span class=\"mord mathnormal\">L</span><span class=\"mord\"><span class=\"mord mathnormal\">i</span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.7713em;\"><span style=\"top:-3.063em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mbin mtight\">+</span></span></span></span></span></span></span></span></span></span></span>更快消耗完而进一步缩短过渡时间，故而SEI是体系中锂离子的扩散控制步骤。","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[147,148]},"content":"4.沉积-溶解模型","children":[{"type":"list_item","depth":4,"payload":{"lines":[151,152]},"content":"从热动力学角度来解释死锂以及表面颗粒状堆积锂产生的过程和原由。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[153,154]},"content":"在锂金属电池充电过程中，锂负极表面锂沉积的主要过程如下：","children":[{"type":"list_item","depth":5,"payload":{"lines":[155,156]},"content":"<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi>L</mi><msup><mi>i</mi><mo>+</mo></msup></mrow><annotation encoding=\"application/x-tex\">Li^+</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.7713em;\"></span><span class=\"mord mathnormal\">L</span><span class=\"mord\"><span class=\"mord mathnormal\">i</span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.7713em;\"><span style=\"top:-3.063em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mbin mtight\">+</span></span></span></span></span></span></span></span></span></span></span>迁移通过SEI薄膜沉积为锂金属，此时SEI薄膜未有损坏；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[157,158]},"content":"在锂沉积点的位置由于锂对SEI薄膜机械应力的作用使此处有更高的离子电导率，则在此处锂的沉积速度更快而致使锂离子流不均匀，此外锂表面的晶体缺陷和晶界也会引发锂的连续不均匀沉积；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[159,160]},"content":"由于应力的作用，沉积锂的形貌会发生变形来缓解此处应力，此时锂的沉积受限于沉积点曲面位置的锂表面张力，SEI薄膜缺陷，锂表面晶体缺陷和晶界；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[161,162]},"content":"SEI薄膜层在锂生长应力的作用下破损，锂进一步生长为晶须状锂；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[163,164]},"content":"弯折的晶须锂在结点处会发生断裂和溶解，致使产生颗粒状锂和死锂，在高电流密度下或者低温条件下更容易产生大量死锂，这是源于这种条件下的晶须锂更容易断裂。","children":[]}]}]}]},{"type":"heading","depth":2,"payload":{"lines":[183,184]},"content":"三维导电骨架改善锂金属负极","children":[{"type":"blockquote","depth":3,"payload":{"lines":[187,188]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[187,188]},"content":"锂金属负极由于其无基体转化反应的特性而存在无限体积膨胀的问题，针对于此类问题，研究者们设计多种三维导电骨架用于预储锂基体，三维导电骨架不仅可以限制锂的无限体积膨胀而且能够均匀化锂离子流，降低表面有效电流密度，从而抑制锂枝晶的生长。","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[189,190]},"content":"1️⃣石墨烯复合基体","children":[{"type":"ordered_list","depth":4,"payload":{"lines":[194,198],"startIndex":1},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[194,195],"index":1},"content":"1. 石墨烯可以作为一个稳定的金属锂限域骨架；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[195,196],"index":2},"content":"2. 热处理后的石墨烯表面具有亲锂性的含氧官能团，能够促进金属锂的均匀沉积；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[196,198],"index":3},"content":"3. 石墨烯层间表面可以作为一个稳定的人工SEI表面。<br>\n<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure2\">图 2c</a><mark>亲锂性+三维骨架</mark>--<mark>金属氧化物纳米片(如MnO2、Co3O4、SnO2)+石墨烯泡沫骨架</mark>","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[198,200]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[198,199]},"content":"由于金属氧化物能够和金属锂进行氧化还原反应，故而具有优异的亲锂性，在石墨烯泡沫上分别修饰多种金属氧化物纳米片(如MnO2、Co3O4、SnO2)以促进熔融锂进入到石墨烯泡沫骨架中得到复合金属锂电极。","children":[]}]}]},{"type":"heading","depth":3,"payload":{"lines":[200,201]},"content":"2️⃣碳纤维复合基体","children":[{"type":"blockquote","depth":4,"payload":{"lines":[203,204]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[203,204]},"content":"碳纤维的三维结构可以降低有效电流密度，减小锂成核过电势，限制金属锂的体积膨胀，因而碳纤维基体也被广泛应用于锂金属沉积的集流体","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[205,207]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[205,206]},"content":"纯碳纤维亲锂性差--&gt; 表面修饰","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[209,212]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[209,210]},"content":"F3a:焦耳热方法在自支撑碳纤维上沉积了尺寸为40 nm的超细金属Ag颗粒用于诱导锂沉积","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[210,211]},"content":"F3b:化学气相沉积在碳纤维表面修饰一层碳纳米管，并通过高温渗锂实验证明这些碳纳米管不仅能够促进熔融锂渗入到纤维骨架中制备得到复合金属锂电极，而且能够调控锂离子在其表面均匀成核生长","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[211,212]},"content":"F3c:一种负载TiN-VN异质结的柔性碳纤维(TiN-VN@CNFs)，将其分别与硫和金属锂复合，并用于Li-S电池的正极和负极材料","children":[]}]}]},{"type":"heading","depth":3,"payload":{"lines":[212,213]},"content":"3️⃣多孔金属复合基体","children":[{"type":"blockquote","depth":4,"payload":{"lines":[215,216]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[215,216]},"content":"由于高电子电导率和结构稳定性，金属基体常被应用于负载电极材料的集流体，三维多孔金属基体也被探索应用于预储存锂的基体或者锂电沉积的集流体以限制锂金属的无限体积膨胀和调控锂离子的沉积行为","children":[]}]},{"type":"blockquote","depth":4,"payload":{"lines":[217,218]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[217,218]},"content":"对于金属集流体的主要设计策略集中于两方面，一是设计多孔结构提高表面电化学活性面积提高储锂的空间，二是合金层或亲锂性化合物修饰金属基体，起到诱导锂成核生长和均匀化锂离子流的作用。","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[221,229]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[221,222]},"content":"F4a: 将泡沫镍应用于预储存锂的三维基体，由于泡沫镍的高温稳定结构和高电子电导率等特点，在加热温度为400 ℃的条件下将熔融金属锂渗入到泡沫镍的三维多孔骨架中构成泡沫镍和金属锂的复合电极(Li-Ni composite)","children":[{"type":"list_item","depth":6,"payload":{"lines":[222,223]},"content":"泡沫镍表面的突起结构能够起到调控锂离子沉积作用，抑制锂枝晶的生长。","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[223,224]},"content":"<mark>可以制备表面裂纹，引导锂反向沉积，但最后怎么使得SEI膜更平整？</mark>","children":[]}]},{"type":"list_item","depth":5,"payload":{"lines":[224,225]},"content":"F4b:   纳米线结构材料由于其较高的比表面积和一维结构能够构起到限域锂和均匀化离子流等作用。通过氧化还原法在Cu集流体表面构筑三维亚微孔铜纳米线应用于锂沉积储存的集流体","children":[{"type":"list_item","depth":6,"payload":{"lines":[225,226]},"content":"<mark>想到纳米刷，MOF</mark>","children":[]}]},{"type":"list_item","depth":5,"payload":{"lines":[226,227]},"content":"F4c:   与锂形成合金化合物的材料一般能够降低锂成核过电势和诱导锂成核。","children":[{"type":"list_item","depth":6,"payload":{"lines":[227,228]},"content":"在铜集流体表面构筑了铜纤维结构用于锂沉积的骨架(3D Cu)，然后通过磁控溅射的方法在铜纤维表面沉积了一层Al层(D Cu@Al)，该Al层在锂电沉积时可以和锂形成一层LiAl合金层用作于锂金属的成核和生长","children":[]}]}]}]},{"type":"heading","depth":3,"payload":{"lines":[229,230]},"content":"4️⃣粉体锂金属负极","children":[{"type":"blockquote","depth":4,"payload":{"lines":[232,233]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[232,233]},"content":"以上几种复合金属基体主要集中于三维自支撑骨架，在本部分主要讨论粉体材料用于储存和保护锂金属负极。<mark>粉体材料相对于三维自支撑骨架的优点主要在于其大面积合成制备工艺更加简单从而可以规模化制备复合锂金属负极。</mark>","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[235,239]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[235,236]},"content":"F5a： 通过喷雾干燥的方法合成碳纳米管(CNTs)团簇球，然后通过高温渗锂的方式将适量熔融锂渗入到CNTs粉体基体构成Li-CNTs复合粉体负极，最后将该粉体负极压在铜集流体表面以用于电化学性能测试。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[236,237]},"content":"F5b:金属有机框架材料(MOFs)由于其独特的配位方式和形貌结构在近些年广泛被用于催化和储能材料，其中ZIF-8是一种阳离子为Zn2+、有机配位链为二甲基咪唑的典型MOFs材料。碳化的ZIF-8材料(cMOFs)作为储存锂的基体，通过高温渗锂的方式将熔融锂渗入到cMOFs的基体中制备成复合粉体锂负极Li-cMOFs。cMOFs中具有亲锂性的Zn元素可以与锂形成合金从而诱导熔融锂渗入到cMOFs基体中，并且通过Li-Zn二元相图可以知道在Zn含量为0.5% (<em>w</em>)的时候能形成Li-Zn固溶层，可以作为一个缓冲层而能够有效地降低锂沉积过程中的成核过电势。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[237,238]},"content":"F5c: 将适量AlN粉末和球状Li粉混合在一起，再加入少量的碳纳米管压成电极片，在150 ℃条件下加热2 h形成LAN复合锂负极。和Li接触的AlN反应生成高离子电导率Li3N和亲锂性的LiAl合金层，分别起到提高离子扩散动力学和诱导锂成核沉积的作用，其外层高电子电导率的AlN和CNT提高了复合锂负极的电子电导，减小了其极化电压。","children":[]}]}]}]},{"type":"heading","depth":2,"payload":{"lines":[239,240]},"content":"不同基体对锂脱镀电化学过程的影响，四种主要基体构成的锂负极对称电池性能总结:","children":[]},{"type":"heading","depth":2,"payload":{"lines":[244,245]},"content":"电解液及添加剂改善锂金属负极","children":[{"type":"bullet_list","depth":3,"payload":{"lines":[247,252]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[247,248]},"content":"保护锂负极的电解液优化策略:","children":[{"type":"list_item","depth":5,"payload":{"lines":[248,249]},"content":"提高锂盐浓度","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[249,250]},"content":"稳定SEI","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[250,251]},"content":"诱导锂沉积的添加剂策略。","children":[]}]}]},{"type":"blockquote","depth":3,"payload":{"lines":[252,253]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[252,253]},"content":"有机电解液是锂离子/锂金属电池中的“血液”，负责正负极中锂离子的传输，有机电解液由于其有限的电化学稳定窗口，一般会与电极材料发生化学反应生成固/液界面，即SEI薄膜。有机电解液和其中的添加剂一般会参与形成溶剂化锂离子的壳层，在锂金属电池中，溶剂化壳层会参与反应形成锂表面的SEI。因此，通过调控电解液成分、浓度和添加剂能够有效地改变锂金属表面SEI的成分和调节锂离子的沉积行为从而抑制锂枝晶的生长.","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[255,256]},"content":"高浓锂盐电解液","children":[{"type":"blockquote","depth":4,"payload":{"lines":[258,259]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[258,259]},"content":"商业化锂离子电池体系中电解液锂盐是<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi>L</mi><mi>i</mi><mi>P</mi><msub><mi>F</mi><mn>6</mn></msub></mrow><annotation encoding=\"application/x-tex\">LiPF_6</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.8333em;vertical-align:-0.15em;\"></span><span class=\"mord mathnormal\">L</span><span class=\"mord mathnormal\">i</span><span class=\"mord mathnormal\" style=\"margin-right:0.13889em;\">P</span><span class=\"mord\"><span class=\"mord mathnormal\" style=\"margin-right:0.13889em;\">F</span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.3011em;\"><span style=\"top:-2.55em;margin-left:-0.1389em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">6</span></span></span></span><span class=\"vlist-s\"></span></span><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.15em;\"><span></span></span></span></span></span></span></span></span></span>，溶剂为碳酸酯类体系，锂盐浓度一般处于<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mn>1</mn><mi>m</mi><mi>o</mi><mi>l</mi><mo separator=\"true\">⋅</mo><msup><mi>L</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow><annotation encoding=\"application/x-tex\">1 mol·L^{-1}</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.8141em;\"></span><span class=\"mord\">1</span><span class=\"mord mathnormal\">m</span><span class=\"mord mathnormal\">o</span><span class=\"mord mathnormal\" style=\"margin-right:0.01968em;\">l</span><span class=\"mpunct\">⋅</span><span class=\"mspace\" style=\"margin-right:0.1667em;\"></span><span class=\"mord\"><span class=\"mord mathnormal\">L</span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.8141em;\"><span style=\"top:-3.063em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mtight\">−</span><span class=\"mord mtight\">1</span></span></span></span></span></span></span></span></span></span></span></span>左右，此种电解液体系在锂离子电池中比较稳定，并且在此浓度附近电解液具有最优的离子电导率和液体流动性。","children":[]}]},{"type":"blockquote","depth":4,"payload":{"lines":[260,261]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[260,261]},"content":"在<mark>有机电解液体系</mark>中，锂盐中的锂离子和有机溶剂形成溶剂化锂离子，其阴离子也参与溶剂化壳层的形成，当锂离子在锂金属表面沉积时，溶剂化锂离子首先在SEI层进行去溶剂化的过程然后在锂金属表面发生沉积，此时<mark>溶剂化壳层还原分解参与形成SEI的成分</mark>。","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[268,269]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[268,269]},"content":"此外，如图 6d所示，<mark>通过分子能级对比发现LiFSI相对于EC和 DMC具有更低的LUMO (最低非占据分子轨道)能 级从而更容易在Li表面还原分解，LiFSI相对于EC 和DMC具有更低的HOMO (最高分子占据轨道)能 级从而具有更好的高压稳定性</mark>","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[272,275]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[272,273]},"content":"F6a: 当提高电解液锂盐浓度时，锂离子周围具有更多的溶剂化分子，并且自由阴离子能够参与到形成锂离子的溶剂化壳层，当稀释高浓电解液时，自由阴离子参与形成的溶剂化锂离子能够仍然保持，因此构建合适浓度的高浓电解液能够通过调节其溶剂化壳层的成分而进一步调节锂负极表面SEI的成分从而抑制锂枝晶的生长。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[273,274]},"content":"Fan等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b126\">126</a>使用了有机溶剂为EC/DMC (碳酸乙烯酯/碳酸二甲酯)，锂盐浓度为10 mol·L-1 LiFSI的电解液体系应用于全氟化高压锂金属电池。如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure6\">图 6b</a>所示，其中高浓度FSI-阴离子不仅在锂负极表面还原形成富F的SEI层而且在三元正极材料LiNi0.6Co0.2Mn0.2O2 (NCM622)表面氧化形成了含F的正极/电解液界面(CEI)。具有全氟化界面的NCM622锂金属全电池可以稳定充电至4.6 V，远高于普通电解液体系NCM622的4.2 V或者4.3 V的充电截止电压，如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure6\">图 6c</a>所示，10 mol·L-1高浓电解液体系在充电截止电压为4.6 V的条件下能够稳定循环100圈并保持99.1%的库伦效率，同时在Li-Cu电池体系中能够保持99.3%的库伦效率稳定循环250圈，表明该电解液体系形成的氟化界面能够抑制枝晶锂的形成并提高锂负极利用率。","children":[]}]},{"type":"heading","depth":4,"payload":{"lines":[275,276]},"content":"Remains the challenges:","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[279,280]},"content":"SEI稳定添加剂","children":[{"type":"bullet_list","depth":4,"payload":{"lines":[284,288]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[284,285]},"content":"添加剂有较低的LUMO能级和较高的HOMO能级从而能够优先和金属锂反应；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[285,286]},"content":"添加剂和金属锂的反应产物需要保持好的化学和电化学稳定性，具有电子绝缘和离子导通的性质；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[286,287]},"content":"形成的SEI需要保持致密连续的结构。由于LiF具有较高的杨氏模量(~64.9 GPa)和电子绝缘性质(<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mn>1</mn><msup><mn>0</mn><mrow><mo>−</mo><mn>31</mn></mrow></msup><mi>S</mi><mo separator=\"true\">⋅</mo><mi>c</mi><msup><mi>m</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow><annotation encoding=\"application/x-tex\">10^{-31} S·cm^{-1}</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.8141em;\"></span><span class=\"mord\">1</span><span class=\"mord\"><span class=\"mord\">0</span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.8141em;\"><span style=\"top:-3.063em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mtight\">−</span><span class=\"mord mtight\">31</span></span></span></span></span></span></span></span></span><span class=\"mord mathnormal\" style=\"margin-right:0.05764em;\">S</span><span class=\"mpunct\">⋅</span><span class=\"mspace\" style=\"margin-right:0.1667em;\"></span><span class=\"mord mathnormal\">c</span><span class=\"mord\"><span class=\"mord mathnormal\">m</span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.8141em;\"><span style=\"top:-3.063em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mtight\">−</span><span class=\"mord mtight\">1</span></span></span></span></span></span></span></span></span></span></span></span>)<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b144\">144</a>-<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b146\">146</a>，能够很好满足以上对反应产物的几种需求，故而选择合适的含氟添加剂在锂金属表面构筑富含LiF的SEI能够有效地抑制锂枝晶的生长。","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[291,295]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[291,292]},"content":"F7a：在1.0 mol·L-1 LiPF6-EC/DEC电解液体系中添加5% (<em>w</em>) FEC用于保护锂金属负极，由于FEC (-0.87 eV)相比于EC (-0.38 eV)和DEC (0 eV)具有更低的LUMO能级从而能够优先和锂金属反应生成富含LiF的SEI从而使锂离子能够均匀沉积。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[292,293]},"content":"F7b：LiNO3常被应用于锂硫电池体系中醚类电解液添加剂来抑制多硫化物的穿梭和锂枝晶的生长，LiNO3在醚类溶剂中很容易溶解，但是醚类溶剂体系由于其较窄的氧化还原窗口很难应用于高压锂金属电池，所以<mark>对于高压锂金属电池一般选用酯类溶剂体系</mark>，而LiNO3基本不溶于碳酸酯类溶剂中。（加助溶剂：）","children":[{"type":"list_item","depth":6,"payload":{"lines":[293,294]},"content":"结合FEC和LiNO3的优势将LiNO3溶解在DME电解液体系中然后再加入FEC构成醚/酯共溶剂化电解液体系解决了LiNO3不溶于FEC的问题。FEC和LiNO3共同参与形成Li+的溶剂化壳层并在锂负极表面分解生成LiF，Li3N和LiN_x_O_y_等产物，这些产物构成稳定的锂负极SEI并可以引导锂离子的均匀沉积。当使用FEC/LiNO3体系时在1.0 mA·cm-2的电流密度下沉积半小时锂金属断面结构仍然保持平整，而EC/DEC电解液体系生成大量枝晶锂。在扣式和软包电池中FEC/LiNO3电解液体系也展现出了更稳定的全电池循环性能。除以上添加剂外仍然有大量的含F、N、S、B等元素添加剂体系用于稳定SEI膜结构，如LiAsF6 <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b154\">154</a>，LiBOB (双草酸硼酸锂) <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b155\">155</a>，LiDFOB (二氟草酸硼酸锂) <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b156\">156</a>，LiPS (多硫化锂) <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b157\">157</a>，H3BO3<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b158\">158</a>等。","children":[]}]}]}]},{"type":"heading","depth":3,"payload":{"lines":[295,296]},"content":"诱导锂沉积添加剂","children":[{"type":"list_item","depth":4,"payload":{"lines":[299,300]},"content":"F7c: 未添加CsPF6的锂负极表面在沉积Li后生成了大量的锂枝晶，而添加0.05 mol·L-1 CsPF6的锂负极在沉积Li后表面十分光滑平整，表明了CsPF6添加剂可以有效地调节Li+沉积行为。此通过电场自愈合策略也被进一步证明能够有效地调控锂沉积形貌和提升锂金属电池性能。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[300,301]},"content":"人造SEI改善锂金属负极","children":[{"type":"bullet_list","depth":3,"payload":{"lines":[304,306]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[304,305]},"content":"在金属锂循环前于其表面构筑一层结构均匀稳定的，离子导通，电子绝缘的人造SEI是保护锂负极的一种有效的策略。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[305,306]},"content":"由前面电解液部分讨论可知LiF能够钝化SEI膜抑制锂枝晶的生长，故而在金属锂表面设计稳定的富含LiF人造SEI能够保护锂负极。","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[310,319]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[310,311]},"content":"F8a：在350 ℃条件下加热含氟有机物CYTOP来产生氟气(F2)，然后F2和金属锂反应12h在锂表面生成了一层厚度大约380 nm的LiF保护层。<mark>该气固反应构筑LiF人造SEI的实验方法简单且能够规模化制备</mark>","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[311,312]},"content":"F8b：电子绝缘的LiCl可以阻止Li+在保护层表面还原成Li金属，高离子电导的合金锂化合物Li_x_M能够促进Li+快速迁移到合金层下在锂表面还原成Li金属，这两方面的作用抑制了锂枝晶的形成。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[312,313]},"content":"F8c：在240 ℃的条件下加热单质硫产生气体和金属锂反应24 h在锂表面构筑高离子电导率Li2S (~10–5 S·cm–1)无机保护层，合成过程和保护锂负极。","children":[{"type":"list_item","depth":5,"payload":{"lines":[313,314]},"content":"作者通过COMSOL模拟计算得知当Li表面SEI的离子电导率越高时锂离子流分布越均匀，不容易形成枝晶，而传统SEI的锂离子电导率一般都比较低，较慢的离子传输速率会引发锂离子聚集而产生锂枝晶。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[314,315]},"content":"受到此Li2S设计策略启发，Liu等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b184\">184</a>利用低沸点固溶化合物SeS2 (~118 ℃)作为气体蒸发前驱体，将产生的硫化硒气体和金属锂反应生成Li2S/Li2Se混合保护层，由于Se和S是同主族元素且半径比S大，通过DFT计算得知Li2Se的离子迁移能垒比Li2S更低，故而能够进一步提高Li2S体系的离子电导率","children":[]}]},{"type":"list_item","depth":4,"payload":{"lines":[315,316]},"content":"F8d：有机物聚合物由于其较高的韧性和机械稳定性也被作为稳定锂负极固液界面层的研究对象。","children":[{"type":"list_item","depth":5,"payload":{"lines":[316,317]},"content":"当单纯有机聚合物体系的离子电导率无法进一步提高时，需要结合无机物和有机聚合物的优势制备高离子电导率，高韧性的人造SEI层。","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[317,318]},"content":"在金属锂表面构筑了弹性的PAA (聚丙烯酸)保护层，金属锂和聚丙烯酸原位反应生成聚丙烯酸锂，即LiPAA，锂离子的迁移即通过含Li聚合物链段迁移的方式进行。该LiPAA SEI层不仅阻止金属锂和电解液的副反应而且能够自适应调节锂枝晶对SEI层的应力，使金属锂能够在此SEI层下均匀沉积。","children":[]}]}]},{"type":"blockquote","depth":3,"payload":{"lines":[319,320]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[319,320]},"content":"卤化锂保护。","children":[]}]},{"type":"blockquote","depth":3,"payload":{"lines":[321,322]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[321,322]},"content":"第VI主族元素和锂形成的化合物也具有较好的离子电导率和锂负极保护作用。","children":[]}]},{"type":"blockquote","depth":3,"payload":{"lines":[325,326]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[325,326]},"content":"人造SEI策略对锂金属的保护作用具有很大的提升。但是在高锂利用率电池体系中，人造SEI的离子电导率和结构稳定性仍然有待改善，需要研究者们不断的开发出优异的保护策略和探索其内在作用机理以进一步实现高比能量锂金属全电池。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[327,328]},"content":"修饰隔膜保护锂金属负极","children":[{"type":"blockquote","depth":3,"payload":{"lines":[331,332]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[331,332]},"content":"锂二次电池中隔膜的作用是阻隔正负极接触避免发生短路现象，隔膜是允许溶剂化锂离子穿过而不允许电子导通，在锂金属电池中，当锂枝晶刺穿隔膜时则会连接正负极从而引发电池短路着火等安全事故。","children":[]}]},{"type":"blockquote","depth":3,"payload":{"lines":[334,335]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[334,335]},"content":"在商业隔膜上修饰无机或有机材料来提高隔膜抗枝晶应力和调控枝晶生长行为，并且相应的策略可以规模化扩大应用。","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[340,344]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[340,341]},"content":"F9a: 在隔膜负极端表面修饰功能化碳层改变锂枝晶的生长方向从而来抑制锂枝晶的进一步生长。如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure9\">图 9a</a>所示，锂枝晶的顶端电势_φ<em>t高于其底端锂表面电势</em>φ_s <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b209\">209</a>，且枝晶越尖锐顶端和表面电势差越大，其电势差是枝晶生长的驱动力，逐渐生长的锂枝晶会刺穿隔膜并产生大量的死锂。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[341,342]},"content":"F9b: 对苯磺酸(para-benzenesulfonic acid，缩写为pb-SO3H)修饰的功能化纳米碳层先被浸在LiNO3溶液中吸附一些锂离子形成pb-SO3Li，然后在隔膜上涂覆此含锂功能化碳层，由于功能化碳层和锂金属在电池中处于物理接触状态从而具有相同的电势，在锂金属电池充电过程中锂枝晶不仅从锂表面生长也会从功能化碳层表面生长，当两端枝晶顶端触碰时，整体枝晶锂的电势差变为零从而失去锂枝晶生长驱动力，后续的锂则均匀沉积在碳层和锂金属层中间。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[343,344]},"content":"隔膜修饰保护锂负极也会存在一些挑战不可忽略，如隔膜厚度的增加会造成电池能量密度降低、锂离子在溶液体系中扩散路径变长、阻抗增大、极化电压增高等，因此需要合理设计修饰层的厚度及其化学成分。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[344,345]},"content":"全固态锂金属电池(ASSLMBs)","children":[{"type":"ordered_list","depth":3,"payload":{"lines":[347,350],"startIndex":1},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[347,348],"index":1},"content":"1. 固态电解质的锂离子电导率相对于有机电解液较低，造成高电流密度下离子传输受阻，极化增大；","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[348,349],"index":2},"content":"2. 固态电解质和电极材料以及锂金属的固固界面接触阻抗较大，导致界面处离子传输很慢；","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[349,350],"index":3},"content":"3. 锂金属在全固态电池中会沿着电解质晶界生长锂枝晶引发电池短路","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[355,358]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[355,356]},"content":"固态电解质主要分为无机陶瓷固态电解质(ICEs)和有机聚合物固态电解质(SPEs)","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[356,357]},"content":"SPEs一般具有较好的柔韧性，和电极材料具有较低的接触阻抗，但是强度低，能够被锂枝晶穿破；ICEs和电极材料接触较差，但其硬度高，能够阻止锂枝晶的持续生长。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[357,358]},"content":"结合二者的优点，Duan等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b222\">222</a>率先设计了非对称的全固态电解质结构(ASE)，以25 μm后的celgard隔膜作为电解质载体，在正极材料面设计厚度为5.4 μm的PEGMEA (聚乙二醇甲醚丙烯酸酯)聚合物电解质层。","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[360,367]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[360,361]},"content":"金属锂和固态电解质间的接触阻抗也比较大，并且会生成锂枝晶，当电流密度较大时，其高界面接触阻抗则会严重增大电池极化","children":[{"type":"list_item","depth":5,"payload":{"lines":[361,362]},"content":"Duan等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b223\">223</a>在熔融金属锂中加入适量石墨添加剂构成Li-C复合物，该熔融Li-C复合物展现出相对于纯锂更低的流动性和更高的粘度，如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure10\">图 10b</a>所示，然后将该熔融Li-C负极涂覆在石榴型无机陶瓷固态电解质Li6.5La3Zr1.5Ta0.5O12 (LLZTO)上构筑均匀稳定的Li-C/LLZTO界面。研究发现LLZO对Li-C复合物具有更好的兼容性，熔融Li-C复合物能够很好的吸附在LLZTO表面上，而熔融Li很难自发吸附在LLZTO上。通过断面结构图发现Li-C电极和LLZTO电解质紧密接触，界面阻抗在11 Ω·cm2，而Li电极和LLZTO存在几个微米大小的缝隙，界面阻抗高至381 Ω·cm2。","children":[]}]},{"type":"list_item","depth":4,"payload":{"lines":[363,364]},"content":"为了在全固态电池体系中调控锂/电解质界面上的锂离子沉积行为，Zhao等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b224\">224</a>将Al掺杂的Li6.75La3Zr1.75Ta0.25O12 (Al-LLZTO)的粉末加入到溶有锂盐的聚合物体系(PEO/LiTFSI)中并分散均匀，然后将该流延体涂覆在聚四氟乙烯板上并干燥制成均匀的聚合物-无机物固态电解质薄膜(PLL)。由于Al-LLZTO具有较高的离子电导率并且该颗粒的加入减小了PEO聚合物的结晶度从而使PLL在25 ℃离子电导率高达1.12 × 10-5 S·cm-1，并且其阳离子迁移数<em>t</em>+高达0.58，高于PEO/LiTFSI (<em>t</em>+ = 0.37)，1 mol·L-1 LiPF6-EC/DEC (<em>t</em>+ = 0.22)，1 mol·L-1 LiTFSI-DME (<em>t</em>+ = 0.21)。如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure10\">图 10c</a>所示，其中TFSI-阴离子被聚合物基体和无机填充颗粒固定住，使界面处空间电荷和锂离子均匀分布从而诱导锂的均匀沉积，其锂沉积形貌相对于液态体系中更加平整光滑，未出现枝晶状的锂。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[365,366]},"content":"无锂负极构成的锂金属电池受到广泛的研究和关注<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b225\">225</a>, <a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b226\">226</a>，此种电池结构需要正极的锂能够稳定均匀沉积在负极集流体上，并保持较高的锂利用率才可以实现电池的稳定循环。如<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#Figure10\">图 10d</a>所示，Lee等<a href=\"http://www.ccspublishing.org.cn/article/doi/10.3866/PKU.WHXB202006021?viewType=HTML#b227\">227</a>将60 nm的Ag颗粒和30 nm的导电碳黑粉末在Cu集流体上流延涂覆制成Ag/C层，然后使用Ag/C复合物作为无锂负极，Li6PS5Cl为固态电解质，高镍三元LiNi0.90Co0.05Mn0.05O2作为正极材料构件全固态电池。研究发现Ag/C层能够有效地调节锂沉积，当正极材料中的Li沉积到负极中时，锂离子先与Ag形成合金Li9Ag4，然后再成核生长并均匀沉积，研究发现，部分的Ag颗粒会随着锂沉积过程迁移到集流体表面并维持在Ag/C层和集流体之间，在此Ag颗粒的诱导作用下，Li均匀沉积在Cu集流体和Ag/C层中间，当放电时，锂也能够均匀的脱出。当利用此全固态电池体系构建0.6 Ah容量的软包电池时，在电流密度为0.5_C_ (1.0_C_ = 6.8 mA·cm-2)，温度为60 ℃的条件下稳定循环1000圈，并保持99.8%的库伦效率，体现出此种体系全固态电池具有一定商业应用的化潜力。","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[369,373]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[369,370]},"content":"稳定锂负极和电解质界面的策略主要通过以下两方面实现：","children":[{"type":"list_item","depth":5,"payload":{"lines":[370,371]},"content":"通过添加化合物饰锂金属电极来构筑快离子传输和低阻抗的Li/电解质的界面；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[371,372]},"content":"修饰固态电解质以提高其亲锂性和调控锂离子的沉积行为。","children":[]}]},{"type":"list_item","depth":4,"payload":{"lines":[372,373]},"content":"但是固态锂金属电池在高电流密度下的应用仍然具有挑战，需要进一步构建稳定的固固界面和开发出先进的电解质材料。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[377,378]},"content":"Conclusion","children":[]}]},{"type":"heading","depth":1,"payload":{"lines":[387,388]},"content":"👑高性能锂金属电池负极结构设计及界面强化研究进展","children":[{"type":"blockquote","depth":2,"payload":{"lines":[389,396]},"content":"","children":[{"type":"paragraph","depth":3,"payload":{"lines":[389,396]},"content":"金属与金属基复合材料       |<br>\n高性能锂金属电池负极结构设计及界面强化研究进展<br>\n姚诗言, 曾立艳, 刘军*<br>\n华南理工大学材料科学与工程学院,广东省先进储能材料重点实验室,广州 510641<br>\nResearch Progress in Structure Design and Interface Enhancement of Lithium Anode for High-performance Lithium Metal Batteries<br>\nYAO Shiyan, ZENG Liyan, LIU Jun*<br>\nGuangdong Provincial Key Laboratory of Advanced Energy Storage Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[399,400]},"content":"keywords:","children":[{"type":"list_item","depth":3,"payload":{"lines":[400,401]},"content":"若电解液最低未占分子轨道(LUMO)的电位低于阳极电位,则电子会由阳极向电解液转移,引发电解液的本征还原反应,在阳极表面形成一层可以阻碍电子转移的SEI膜。SEI膜阻碍电子传输作用的强度很大程度上取决于SEI膜的厚度。","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[402,403]},"content":"SEI:","children":[]},{"type":"heading","depth":2,"payload":{"lines":[406,407]},"content":"纯锂的无限大体积膨胀","children":[]},{"type":"heading","depth":2,"payload":{"lines":[409,410]},"content":"1.枝晶生长机制-理论模型","children":[{"type":"heading","depth":3,"payload":{"lines":[410,411]},"content":"1️⃣Chazalviel-Brissot模型","children":[]},{"type":"heading","depth":3,"payload":{"lines":[414,415]},"content":"2️⃣Yamaki模型","children":[]},{"type":"heading","depth":3,"payload":{"lines":[419,420]},"content":"3️⃣静电屏蔽模型","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[423,424]},"content":"1.0锂枝晶的主要形态","children":[{"type":"list_item","depth":3,"payload":{"lines":[426,427]},"content":"针状","children":[{"type":"list_item","depth":4,"payload":{"lines":[427,428]},"content":"针状枝晶几乎没有分支,表现出一维形态,是导致电池短路的主要原因。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[428,429]},"content":"针状枝晶倾向于在负极基体和SEI 的晶体缺陷处形核生长。与其他形态的枝晶相比,针状枝晶具有最大且最完整的晶体结构,部分针状枝晶甚至可以长达几十微米,因此其极易刺穿隔膜,引发电池短路。","children":[]}]},{"type":"list_item","depth":3,"payload":{"lines":[429,430]},"content":"苔藓状","children":[{"type":"list_item","depth":4,"payload":{"lines":[430,431]},"content":"苔藓状枝晶是由针状枝晶演变而来。针状枝晶生长时,直径会逐渐增大,后续的Li*易在其晶界处形核生长,形成新的针状枝晶,如此循环往复,最终形成三维形态的苔藓状枝晶。","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[431,432]},"content":"苔藓状枝晶的比表面积较大，因而极易与电解液反应生成SEI 膜,且容易断裂形成“死锂”,这是电池容量衰减的主要原因。","children":[]}]},{"type":"list_item","depth":3,"payload":{"lines":[432,433]},"content":"树枝状","children":[{"type":"list_item","depth":4,"payload":{"lines":[433,434]},"content":"树枝状枝晶是一种理论上的枝晶形态,它要求枝晶能够以合适的速度向各个方向生长,且具有稳定的分支结构,在大多数实验条件下难以得到满足,因此通常用作模拟实验和理论计算的模型。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[441,442]},"content":"锂金属负极结构设计","children":[{"type":"heading","depth":3,"payload":{"lines":[442,443]},"content":"3D集流体","children":[{"type":"heading","depth":4,"payload":{"lines":[446,447]},"content":"导电3D集流体","children":[{"type":"list_item","depth":5,"payload":{"lines":[447,448]},"content":"rGO","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[448,449]},"content":"Cu","children":[]}]},{"type":"heading","depth":4,"payload":{"lines":[449,450]},"content":"不导电3D集流体","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[452,453]},"content":"孔径影响--3D集流体","children":[]},{"type":"heading","depth":3,"payload":{"lines":[460,461]},"content":"表面改性集流体","children":[{"type":"list_item","depth":4,"payload":{"lines":[463,464]},"content":"碳基","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[464,465]},"content":"金属基","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[466,467]},"content":"锂金属负极界面强化","children":[{"type":"bullet_list","depth":3,"payload":{"lines":[470,480]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[470,471]},"content":"高机械强度","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[471,473]},"content":"高化学稳定性<br>\n理想的SEI 应具有以下性质:","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[473,474]},"content":"低电子电导率,阻止Li+直接在SEI上沉积;","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[474,475]},"content":"高Li<em>电导率,实现Li</em>的快速传输","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[475,476]},"content":"均匀的形貌和组成,促进Li+均匀沉积","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[476,477]},"content":"适当的韧性和弹性,适应电池循环过程中的体积变化","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[477,478]},"content":"一定的力学强度,抑制锂枝晶生长","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[478,479]},"content":"良好的致密性和化学稳定性,阻止锂金属与电解液的副反应。","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[480,481]},"content":"原位SEI膜","children":[]},{"type":"heading","depth":3,"payload":{"lines":[483,484]},"content":"人工SEI膜","children":[]}]}]},{"type":"heading","depth":1,"payload":{"lines":[488,489]},"content":"👑锂金属电池中复合固态电解质与负极界面的研究进展","children":[{"type":"blockquote","depth":2,"payload":{"lines":[493,494]},"content":"","children":[{"type":"paragraph","depth":3,"payload":{"lines":[493,494]},"content":"有机-无机复合固态电解质兼顾无机固态电解质和有机固态电解质的优势，具有较高离子电导率和一定的力学强度","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[495,496]},"content":"固态电解质(SSE)","children":[{"type":"bullet_list","depth":3,"payload":{"lines":[499,502]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[499,500]},"content":"界面接触","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[500,501]},"content":"界面反应层","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[501,502]},"content":"锂离子在负极界面的沉积","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[506,507]},"content":"界面接触","children":[{"type":"bullet_list","depth":4,"payload":{"lines":[508,511]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[508,509]},"content":"没有物质交换、不发生反应的物理接触","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[509,510]},"content":"发生化学反应的化学接触","children":[]}]},{"type":"blockquote","depth":4,"payload":{"lines":[511,512]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[511,512]},"content":"界面接触可以分为没有物质交换、不发生反应的物理接触，以及发生化学反应的化学接触","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[513,515]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[513,514]},"content":"化学接触被视为固态电解质与锂金属因热力学不稳定而产生化学反应的接触过程，而随之生成的界面反应层根据界面的热力学和动力学稳定性一般被划分为：热力学稳定型界面、混合导体型界面和亚稳态型界面，固态电解质与锂金属之间存在的界面层普遍为后两者:","children":[]}]}]},{"type":"heading","depth":3,"payload":{"lines":[521,522]},"content":"固态电池中枝晶生长","children":[{"type":"list_item","depth":4,"payload":{"lines":[523,524]},"content":"(1)物理接触不良：产生的缝隙为枝晶生长提供了自由空间；","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[524,525]},"content":"(2)生成非理想的界面层：若界面层不均匀存在裂纹，将会导致不均匀的锂成核；若界面层为反应和混合导电界面，锂枝晶甚至可以直接沉积并生长在电解质内部的晶界或空隙中；","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[525,526]},"content":"(3)固态电解质有缺陷：表面出现孔洞，给锂枝晶提供生长环境；若固态电解质在晶界的锂离子扩散速率高于晶粒，晶界处的锂枝晶将会优先沉积和溶解。","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[527,528]},"content":"锂离子在聚合物固态电解质和负极界面的沉积模式包括尖端生长、径向生长和多方向生长。","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[534,535]},"content":"固态电解质包括无机固态电解质聚合物固态电解质和复合固态电解质","children":[{"type":"list_item","depth":3,"payload":{"lines":[536,537]},"content":"无机固态电解质具有高离子导电率，但是脆性大、成本高、与电极的固固接触带来较大界面电阻。","children":[{"type":"list_item","depth":4,"payload":{"lines":[537,538]},"content":"无机固态电解质包括氧化物电解质和硫化物电解质","children":[{"type":"list_item","depth":5,"payload":{"lines":[538,539]},"content":"氧化物电解质一般拥有较高的力学强度，不易发生形变但不能适应充放电过程中极片的体积变化；","children":[]},{"type":"list_item","depth":5,"payload":{"lines":[539,540]},"content":"硫化物电解质的弹性模量和断裂韧度适中，与极片的界面接触比较好但存在稳定性的问题","children":[]}]}]},{"type":"list_item","depth":3,"payload":{"lines":[540,541]},"content":"聚合物电解质具有优越的柔韧特性，这使其可与当前锂电池生产工艺兼容，有利于规模化应用；但是其室温离子电导率仍然较低，限制了其实用化进程。","children":[{"type":"list_item","depth":4,"payload":{"lines":[541,542]},"content":"聚合物固态电解质弹性模量低，Monroe和Newman理论预测要想阻挡锂枝晶的刺穿，聚合物电解质的剪切模量需要高于金属锂(Li剪切模量为4.25 GPa)的2倍","children":[]},{"type":"list_item","depth":4,"payload":{"lines":[542,543]},"content":"当前报道的提升聚合物电解质离子导电率的方法，主要包括：对聚合物进行共聚嵌段、交联、增塑、高分子共混、界面修饰等。其中，将无机填料或有机多孔填料与聚合物电解质相混合制备复合电解质的方法受到越来越多关注。","children":[]}]},{"type":"list_item","depth":3,"payload":{"lines":[543,544]},"content":"复合固态电解质兼顾无机固态电解质和有机固态电解质的优势，具有较高离子电导率和一定的力学强度。","children":[{"type":"list_item","depth":4,"payload":{"lines":[544,545]},"content":"无机或有机填料、骨架提供了能够抑制锂枝晶生长可能性的力学强度，而聚合物电解质的存在使得固态电解质更能有效地接触金属锂负极，因此通过调整复合电解质中聚合物和填料的成分、占比可有效调节电解质的力学性能。","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[545,546]},"content":"为了改善负极界面，研究思路包括以下方面：","children":[]},{"type":"heading","depth":2,"payload":{"lines":[549,550]},"content":"1️⃣1 构筑界面“软接触”","children":[{"type":"heading","depth":3,"payload":{"lines":[551,552]},"content":"WHY:调节复合电解质组分来改变力学性能，减小界面的接触阻抗","children":[]},{"type":"heading","depth":3,"payload":{"lines":[552,553]},"content":"HOW:","children":[{"type":"heading","depth":4,"payload":{"lines":[553,554]},"content":"①适量共混具有不同力学性能的其他聚合物-----增加“软接触”","children":[]},{"type":"heading","depth":4,"payload":{"lines":[560,561]},"content":"②液相疗法是解决界面“硬接触”最方便的方案之一","children":[]},{"type":"heading","depth":4,"payload":{"lines":[564,565]},"content":"③ 原位聚合","children":[{"type":"paragraph","depth":5,"payload":{"lines":[565,566]},"content":"原位聚合主要是通过热引发、紫外引发等方法在固态电解质和锂金属界面间原位聚合形成适应间隙的聚合物层，以此改善界面接触","children":[]}]}]}]},{"type":"heading","depth":2,"payload":{"lines":[566,567]},"content":"2️⃣2 调控固态电解质的力学性能：刚柔并济","children":[{"type":"paragraph","depth":3,"payload":{"lines":[570,573]},"content":"孙学良等研究了不同粒径石榴石复合电解质从CIP到PIC对枝晶的抑制效果的同时，设计“三明治”型多层复合电解质，较柔软的复合层在两侧以提升与固态电极的接触，而高力学强度的复合层在中间以抑制锂枝晶:<br>\n<img src=\"http://html.rhhz.net/CLGC/html/PIC/clgc-49-6-33-6.jpg\" alt=\"\"><br>\n图 6 PIC-5 μm, CIP-200 nm和分层三明治型复合电解质的示意图","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[575,576]},"content":"3️⃣3 实现锂离子的均匀沉积","children":[{"type":"blockquote","depth":3,"payload":{"lines":[577,579]},"content":"","children":[{"type":"paragraph","depth":4,"payload":{"lines":[577,579]},"content":"锂金属具有极强的还原性，会导致聚合物在锂负极表面自发分解生成还原产物，形成界面反应层。锂负极与不同组分的聚合物会生成不同的界面反应层，致密的界面反应层可以阻挡电解质和负极发生进一步反应，因此设计合理的界面层是关键<br>\n稳定的界面反应层是良好的离子导体，锂离子可以穿过界面反应层在电极表面沉积，但因为锂负极、固态电解质和界面反应层自身电势、电化学稳定性的问题，以及存在的过充过放操作，常导致锂离子沉积不均匀甚至锂枝晶析出最后刺破电解质使电池失效","children":[]}]},{"type":"bullet_list","depth":3,"payload":{"lines":[580,582]},"content":"","children":[{"type":"list_item","depth":4,"payload":{"lines":[580,581]},"content":"提升复合电解质本身的离子迁移数也可以有效降低锂离子在界面的积累，从而降低因浓度梯度的提高而产生的较大的过电位，抑制锂枝晶的生长","children":[]}]}]}]},{"type":"heading","depth":1,"payload":{"lines":[582,583]},"content":"👑单原子催化——概念、方法与应用","children":[{"type":"heading","depth":2,"payload":{"lines":[588,589]},"content":"KEYWORDS","children":[{"type":"list_item","depth":3,"payload":{"lines":[589,590]},"content":"单原子的存在能够降低氧空位的形成能垒。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[590,591]},"content":"发现 Ｍ１ｄ 带中心明显向高能方向移动，因此催化剂具有更多的空 ｄ 轨道从而 ＣＯ 与 Ｏ２ 吸附分子具有更强的相互作用。 他们又考察了 Ｏ２ 的吸附，发现Ｏ２⁃ｐ 轨道与 Ｍ⁃ｄ（Ｍ ＝ Ｐｔ，Ｒｈ 和 Ｐｄ）轨道发生明显杂化，使 Ｏ２ 更易活化便于 ＣＯ 氧化。    PDOS看轨道之间的杂化，杂化部分越多，范围越广，吸附能越大，互相作用越强。","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[591,592]},"content":"QUICK INTRO","children":[{"type":"list_item","depth":3,"payload":{"lines":[593,595]},"content":"单原子催化剂兼具均相催化剂均匀单一的活性中心和多相催化剂结构稳定易分离的特点，将<br>\n多相催化与均相催化联系在一起。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[595,596]},"content":"单原子催化剂不仅金属负载量极低而且极大地提高了金属原子的利用效率；能够改变催化剂上活性组分对不同分子的吸附／ 脱附选择性，从而影响反应动力学。","children":[]},{"type":"list_item","depth":3,"payload":{"lines":[596,598]},"content":"单原子催化剂同样也存在不足，当金属粒子减小到单原子水平时，比表面积急剧增大，导致金属表面自由能急剧增加，在制备和反应时极易发生团聚耦合形成大的团簇，从而导致催化剂失活，这是制备单原子催化剂所面临的巨大挑战。<br>\n<img src=\"https://ekl4pics.oss-cn-beijing.aliyuncs.com/eklblogpics/20230720093345-420.png\" alt=\"image.png\">","children":[]}]},{"type":"heading","depth":2,"payload":{"lines":[599,600]},"content":"单原子催化剂的制备与特性","children":[{"type":"heading","depth":3,"payload":{"lines":[601,602]},"content":"要解决的问题：烧结成团簇","children":[]},{"type":"heading","depth":3,"payload":{"lines":[603,604]},"content":"基底选择--负载基底：","children":[{"type":"heading","depth":4,"payload":{"lines":[604,605]},"content":"金属及金属氧化物","children":[]},{"type":"heading","depth":4,"payload":{"lines":[606,607]},"content":"二维材料","children":[{"type":"heading","depth":5,"payload":{"lines":[607,608]},"content":"石墨烯：","children":[{"type":"list_item","depth":6,"payload":{"lines":[608,609]},"content":"石墨烯具有高比表面积、高的导电性、独特的结构特点以及潜在的低制造成本等优势，使其成为一种性能优良的催化剂载体。石墨烯薄片上引入Ｃ空穴可以提高石墨烯和Pt的相互作用，形成的金属团簇结构更稳定。","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[609,610]},"content":"石墨烯经高能原子轰击可以产生 Ｃ 空穴，单原子来填补 Ｃ 空穴从而稳定地附着在石墨烯表层。","children":[]}]},{"type":"heading","depth":5,"payload":{"lines":[610,611]},"content":"六方氮化硼（ ｈ⁃ＢＮ）","children":[{"type":"list_item","depth":6,"payload":{"lines":[611,612]},"content":"化学和热稳定性","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[612,613]},"content":"Ｂ—Ｎ 键的高电离度及可能存在的 Ｂ 或 Ｎ 空穴为提高单原子催化剂活性提供了很大的可能性","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[613,614]},"content":"Ｂ 空穴更适用于 ＣＯ 氧化反应，并且 ｈ⁃ＢＮ 经原子轰击更易产生 Ｂ空穴","children":[]}]},{"type":"heading","depth":5,"payload":{"lines":[614,615]},"content":"分子筛：","children":[{"type":"list_item","depth":6,"payload":{"lines":[615,616]},"content":"金属氧化物载体，其表面物种不均一，可能存在空位等。","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[616,618]},"content":"作为对比，分子筛具有金属氧化物不可比拟的优点，其结构规整有序，能为金属活性组分提供<br>\n高度均一的附着位点，并且负载活性组分后的分子筛结构不变且易于表征。","children":[]},{"type":"list_item","depth":6,"payload":{"lines":[618,619]},"content":"借助金属有机配合物前驱体与分子筛的强相互作用，然后经过焙烧或氧化等操作，配体快速脱落，可以制备出原子级分散均一的催化剂。","children":[]}]}]}]}]},{"type":"heading","depth":2,"payload":{"lines":[620,621]},"content":"制备方法","children":[{"type":"heading","depth":3,"payload":{"lines":[622,623]},"content":"1️⃣质量分离软着陆法","children":[{"type":"paragraph","depth":4,"payload":{"lines":[623,624]},"content":"高频激光蒸发源使金属气化，利用质谱仪精确调控，使不同尺寸金属粒子负载到载体表面","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[627,628]},"content":"2️⃣共沉淀法","children":[{"type":"blockquote","depth":4,"payload":{"lines":[628,629]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[628,629]},"content":"首先将贵金属前驱物（氯铂酸和氯铱酸）的水溶液和硝酸铁溶液以合适的比例在碱性环境中搅拌条件下混合滴定，得到的沉淀物经过过滤、洗涤和焙烧，最终得到单原子催化 剂。","children":[]}]},{"type":"bullet_list","depth":4,"payload":{"lines":[630,632]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[630,631]},"content":"通过微调共沉淀的温度和 ｐＨ 值等制备参数来调控单原子的负载量，该方法实现了单原子催化剂的简单化学法制备。","children":[]}]}]},{"type":"heading","depth":3,"payload":{"lines":[632,633]},"content":"3️⃣浸渍法","children":[{"type":"blockquote","depth":4,"payload":{"lines":[635,636]},"content":"","children":[{"type":"list_item","depth":5,"payload":{"lines":[635,636]},"content":"Gates 等将焙烧后的分子筛NaY 浸渍在溶有<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi>A</mi><mi>u</mi><mo stretchy=\"false\">(</mo><mi>C</mi><msub><mi>H</mi><mn>3</mn></msub><msub><mo stretchy=\"false\">)</mo><mn>2</mn></msub><mo stretchy=\"false\">(</mo><mi>a</mi><mi>c</mi><mi>a</mi><mi>c</mi><mo stretchy=\"false\">)</mo><mo stretchy=\"false\">(</mo><mi>a</mi><mi>c</mi><mi>a</mi><mi>c</mi><mo>:</mo><mtext>乙酰丙酮</mtext><mo stretchy=\"false\">)</mo></mrow><annotation encoding=\"application/x-tex\">Au( CH_3 )_2 ( acac) ( acac:乙酰丙酮)</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:1em;vertical-align:-0.25em;\"></span><span class=\"mord mathnormal\">A</span><span class=\"mord mathnormal\">u</span><span class=\"mopen\">(</span><span class=\"mord mathnormal\" style=\"margin-right:0.07153em;\">C</span><span class=\"mord\"><span class=\"mord mathnormal\" style=\"margin-right:0.08125em;\">H</span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.3011em;\"><span style=\"top:-2.55em;margin-left:-0.0813em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">3</span></span></span></span><span class=\"vlist-s\"></span></span><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.15em;\"><span></span></span></span></span></span></span><span class=\"mclose\"><span class=\"mclose\">)</span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.3011em;\"><span style=\"top:-2.55em;margin-left:0em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">2</span></span></span></span><span class=\"vlist-s\"></span></span><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.15em;\"><span></span></span></span></span></span></span><span class=\"mopen\">(</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mclose\">)</span><span class=\"mopen\">(</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mspace\" style=\"margin-right:0.2778em;\"></span><span class=\"mrel\">:</span><span class=\"mspace\" style=\"margin-right:0.2778em;\"></span></span><span class=\"base\"><span class=\"strut\" style=\"height:1em;vertical-align:-0.25em;\"></span><span class=\"mord cjk_fallback\">乙酰丙酮</span><span class=\"mclose\">)</span></span></span></span>的正戊烷溶液中,蒸干溶剂,得到负载量为1wt% Au的单原子催化剂。从 STEM , EXAFS及lR表征结果推测得出前驱体<span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi>A</mi><mi>u</mi><mo stretchy=\"false\">(</mo><mi>C</mi><msub><mi>H</mi><mn>3</mn></msub><msub><mo stretchy=\"false\">)</mo><mn>2</mn></msub><mo stretchy=\"false\">(</mo><mi>a</mi><mi>c</mi><mi>a</mi><mi>c</mi><mo stretchy=\"false\">)</mo></mrow><annotation encoding=\"application/x-tex\">Au( CH_3)_2 ( acac)</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:1em;vertical-align:-0.25em;\"></span><span class=\"mord mathnormal\">A</span><span class=\"mord mathnormal\">u</span><span class=\"mopen\">(</span><span class=\"mord mathnormal\" style=\"margin-right:0.07153em;\">C</span><span class=\"mord\"><span class=\"mord mathnormal\" style=\"margin-right:0.08125em;\">H</span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.3011em;\"><span style=\"top:-2.55em;margin-left:-0.0813em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">3</span></span></span></span><span class=\"vlist-s\"></span></span><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.15em;\"><span></span></span></span></span></span></span><span class=\"mclose\"><span class=\"mclose\">)</span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.3011em;\"><span style=\"top:-2.55em;margin-left:0em;margin-right:0.05em;\"><span class=\"pstrut\" style=\"height:2.7em;\"></span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">2</span></span></span></span><span class=\"vlist-s\"></span></span><span class=\"vlist-r\"><span class=\"vlist\" style=\"height:0.15em;\"><span></span></span></span></span></span></span><span class=\"mopen\">(</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mord mathnormal\">a</span><span class=\"mord mathnormal\">c</span><span class=\"mclose\">)</span></span></span></span>最初物理吸附在分子筛NaY表面的Al位点。发生CO氧化反应后, acac配体快速脱落,形成化学吸附在分子筛骨架上,得到分子筛为载体的单原子Au催化剂。分子筛NaY催化剂的制备和处理过程要保持无水无氧状态,避免与有机金属化合物反应。负载Rh的脱铝分子筛Y催化剂的制备过程类似于上述过程。","children":[]}]},{"type":"blockquote","depth":4,"payload":{"lines":[640,641]},"content":"","children":[{"type":"paragraph","depth":5,"payload":{"lines":[640,641]},"content":"comment: 首次提出的张涛后续有没有使用不同的方法合成，归纳哪一类型的材料适用什么方法合成。","children":[]}]}]},{"type":"heading","depth":3,"payload":{"lines":[642,643]},"content":"4️⃣原子层沉积法","children":[{"type":"list_item","depth":4,"payload":{"lines":[644,647]},"content":"沉积参数精确可控,沉积均匀性和重复性好<br>\n<summary>case</summary><br>\n<details>","children":[]}]},{"type":"heading","depth":3,"payload":{"lines":[652,653]},"content":"5️⃣反 Ostwald 熟化法","children":[]},{"type":"heading","depth":3,"payload":{"lines":[663,664]},"content":"6️⃣逐步还原法","children":[]},{"type":"heading","depth":3,"payload":{"lines":[666,667]},"content":"7️⃣固相熔融法","children":[{"type":"paragraph","depth":4,"payload":{"lines":[667,669]},"content":"将 ＳｉＯ２ 与 Ｆｅ２ ＳｉＯ４ 在高纯氩气氛下混合球磨，在空气气氛下高温煅烧再经硝酸洗涤、<br>\n干燥后得到硅化物晶格限域的单中心铁催化剂","children":[]}]}]},{"type":"heading","depth":2,"payload":{"lines":[670,671]},"content":"性能特征","children":[]},{"type":"heading","depth":2,"payload":{"lines":[682,683]},"content":"单原子催化剂的结构表征","children":[{"type":"heading","depth":3,"payload":{"lines":[690,691]},"content":"球差校正高分辨透射电镜","children":[]},{"type":"heading","depth":3,"payload":{"lines":[693,694]},"content":"原子力显微镜（ＡＦＭ）","children":[]},{"type":"heading","depth":3,"payload":{"lines":[697,698]},"content":"Ｘ 射线吸收精细结构","children":[]}]}]}],"payload":{}},{})</script>
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