In Situ Chemical Lithiation Transforms Diamond-Like Carbon into an Ultrastrong Ion Conductor for Dendrite-Free Lithium-Metal Anodes
In Situ Chemical Lithiation Transforms Diamond-Like Carbon into an Ultrastrong Ion Conductor for Dendrite-Free Lithium-Metal Anodes
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原位化学锂化将类金刚石碳转变为超强离子导体，用于无枝晶锂金属阳极
DOI：
10.1002/adma.202100793
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发表时间：
2021-07-31
影响因子：
29.4
通讯作者：
Tang, Yongbing
中科院分区：
文献类型：
--
作者：
Li, Zhongzhong;Peng, Manqi;Tang, Yongbing
锂金属阳极具有理论容量大、氧化还原电位低的优点，在下一代电池中具有广阔的应用前景。然而，锂枝晶在循环过程中的生长给锂金属阳极的实际应用带来了巨大的安全问题。本文报道了一种有效抑制锂枝晶生长的方法，即在聚丙烯（PP）分离器上涂覆一层超薄的类金刚石碳（DLC）。理论计算表明，DLC涂层一旦与锂金属阳极组装，就会发生原位化学锂化，将DLC/PP分离器转变为优异的3D锂离子导体。这种原位锂化DLC/PP分离器不仅可以通过其固有的高模量（接近100 GPa）来机械地抑制锂枝晶的生长，而且可以均匀地重新分配锂离子，从而获得无枝晶的锂沉积。DLC/PP分离器的双重效应导致在3 mA cm（-2）的高电流密度下，锂电镀/剥离的稳定循环（超过4500小时）。值得注意的是，该方法在Li || LiFePO4硬币电池中实现了在5℃下超过1000次稳定循环，容量保持率约为71%，在Li || LiNi0.5Co0.3Mn0.2O2袋电池中实现了在0.2℃下超过200次稳定循环，阴极质量负载约为9 mg cm（-2）。
Lithium (Li)-metal anodes are of great promise for next-generation batteries due to their high theoretical capacity and low redox potential. However, Li-dendrite growth during cycling imposes a tremendous safety concern on the practical application of Li-metal anodes. Herein, an effective approach to suppress Li-dendrite growth by coating a polypropylene (PP) separator with a thin layer of ultrastrong diamond-like carbon (DLC) is reported. Theoretical calculations indicate that the DLC coating layer undergoes in situ chemical lithiation once assembled with the lithium-metal anode, transforming the DLC/PP separator into an excellent 3D Li-ion conductor. This in situ lithiated DLC/PP separator can not only mechanically suppress Li-dendrite growth by its intrinsically high modulus (approximate to 100 GPa), but also uniformly redistributes Li ions to render dendrite-free lithium deposition. The twofold effects of the DLC/PP separator result in stable cycling of lithium plating/stripping (over 4500 h) at a high current density of 3 mA cm(-2). Remarkably, this approach enables more than 1000 stable cycles at 5 C with a capacity retention of approximate to 71% in a Li || LiFePO4 coin cell and more than 200 stable cycles at 0.2 C in a Li || LiNi0.5Co0.3Mn0.2O2 pouch cell with cathode mass loading of approximate to 9 mg cm(-2).