Intercalation-conversion hybrid cathodes enabling Li-S full-cell architectures with jointly superior gravimetric and volumetric energy densities
Intercalation-conversion hybrid cathodes enabling Li-S full-cell architectures with jointly superior gravimetric and volumetric energy densities
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DOI：
10.1038/s41560-019-0351-0
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发表时间：
2019-05-01
期刊：
影响因子：
56.7
通讯作者：
Li, Ju
中科院分区：
文献类型：
--
作者：
Xue, Weijiang;Shi, Zhe;Li, Ju
在锂硫电池的研究中，一种常见的做法是使用高电极孔隙率和过量的电解质来提高硫比容量。本文提出了一种将嵌入型Mo6S8与转换型硫结合在一起的密集嵌入-转换混合阴极，以实现Li-S充满电池。机械硬度高的Mo6S8具有快速的锂离子传输能力、高电子导电性、有效容量贡献和对多硫化物的高亲和力，是固定化硫种并释放其高重量容量的理想骨架。据报道，在低碳含量（约10 wt%）、低电解质/活性物质比（约1.2 μ l mg(-1)）、低阴极孔隙率（约55 vol%）和高质量负载（约10 mg cm(-2)）的实际条件下，循环稳定性和速率能力得到了提高。基于混合阴极和2倍过量锂金属阳极组装的袋状电池能够同时提供366 Wh kg（-1）的重量能量密度和581 Wh kg（-1）的体积能量密度。
A common practise in the research of Li-S batteries is to use high electrode porosity and excessive electrolytes to boost sulfur-specific capacity. Here we propose a class of dense intercalation-conversion hybrid cathodes by combining intercalation-type Mo6S8 with conversion-type sulfur to realize a Li-S full cell. The mechanically hard Mo6S8 with fast Li-ion transport ability, high electronic conductivity, active capacity contribution and high affinity for lithium polysulfides is shown to be an ideal backbone to immobilize the sulfur species and unlock their high gravimetric capacity. Cycling stability and rate capability are reported under realistic conditions of low carbon content (similar to 10 wt%), low electrolyte/active material ratio (similar to 1.2 mu l mg(-1)), low cathode porosity (similar to 55 vol%) and high mass loading (>10 mg cm(-2)). A pouch cell assembled based on the hybrid cathode and a 2x excess Li metal anode is able to simultaneously deliver a gravimetric energy density of 366 Wh kg (-1) and a volumetric energy density of 581 Whl(-1).