The gap between long lifespan Li-S coin and pouch cells: The importance of lithium metal anode protection
The gap between long lifespan Li-S coin and pouch cells: The importance of lithium metal anode protection
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DOI：
10.1016/j.ensm.2016.09.003
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发表时间：
2017-01-01
影响因子：
20.4
通讯作者：
Zhang, Qiang
中科院分区：
文献类型：
--
作者：
Cheng, Xin-Bing;Yan, Chong;Zhang, Qiang
锂硫（Li-S）电池由于其非常高的理论能量密度（2600 Wh kg（-1））、低成本和无毒而被强烈认为是下一代能量存储装置。多硫化锂（LiPS）在正极中的穿梭和锂在负极中的枝晶生长是锂硫电池实际应用中最棘手的问题之一。通过高效的阴极和膜设计，LiPS可以有效地被捕获在阴极侧，并且硬币电池提供2000次循环的上级循环性能。当硬币电池策略被移植到袋电池时，应进一步探索实现长寿命Li-S袋电池的可能性。在此，探索了硬币电池和袋式电池之间的间隙，并探索了Li-S袋式电池的失效机理。与LiPS穿梭问题相比，Li金属粉化和诱导极化是导致软包电池失效的主要原因。电化学循环性能和非原位形貌表征表明，循环过程中Li离子的连续剥离/电镀导致Li枝晶生长，使更多的新鲜Li暴露在电解液中，并导致死Li粉的形成。因此，Li离子扩散阻力增大，库仑效率逐渐降低。当用新鲜的Li金属更新循环的Li阳极时，具有循环的阴极的Renaissance电池与新鲜的阳极相比在0.1C下表现出从314到1030 mA h g（-1）的改进的放电容量。相对于在大多数情况下在硬币电池中被忽视的作用，Li金属阳极极大地影响Li-S袋电池的长期循环性能。如何有效地保护锂金属阳极，以实现高能量密度、大容量、安全的锂硫电池，是今后锂硫电池研究的重点。(C)2017爱思唯尔B. V.保留所有权利。
Lithium-sulfur (Li-S) batteries have been strongly regarded as next-generation energy storage devices for their very high theoretical energy density (2600 Wh kg(-1)), low cost, and non-toxicity. Li polysulfide (LiPS) shuttle in the cathode and Li dendrite growth in the anode are among the toughest issues on the practical applications of Li-S batteries. By efficient cathode and membrane design, LiPS can be effectively trapped in the cathode side and the coin cells deliver a superior cycling performance of 2000 cycles. When the coin cell strategy is transplanted to a pouch cell, the possibility to achieve a long-lifespan Li-S pouch cell should be further explored. Herein, the gaps between the coin and pouch cell were probed and the failure mechanism of a Li-S pouch cell was explored. Compared with LiPS shuttle issue, Li metal powdering and the induced polarization are more responsible for pouch cell failure. Electrochemical cycling performance and ex-situ morphology characterization indicated that the continuously striping/plating of Li ions results in Li dendrite growth during cycling test, which exposes more fresh Li to electrolyte and induces the formation of dead Li powder. Therefore, the Li ion diffusion resistance is increased and the Coulombic efficiency is reduced gradually. When the cycled Li anode was updated by a fresh Li metal, the renaissance cell with cycled cathode vs fresh anode exhibited an improved discharge capacity from 314 to 1030 mA h g(-1) at 0.1 C. Relatively to a neglected role in coin cells in most cases, Li metal anode tremendously affects long-term cycling performance of Li-S pouch cells. More attentions should be concentrated on efficiently protecting Li metal anode to achieve large capacity and safe Li-S cells with high energy density. (C) 2017 Elsevier B.V. All rights reserved.