江苏师范大学赖超团队报道了实现长寿命522 Wh kg^-1锂金属袋电池的复合添加剂工程。相关研究成果发表在2024年10月8日出版的《德国应用化学》。

将高压阴极与锂金属阳极相匹配，是开发超高能量密度超过500 Wh kg^-1的可充电电池的最可行的技术方法。然而，电解质/电极界面膜和截止电压高于4.3V的商用电解质的不稳定性，仍然是一个主要问题。

该文中，研究人员提出，通过使用含氟碳酸乙烯酯（FEC）、十六烷基三甲基氯化铵（CTAC）和三（五氟苯基）硼烷（TPFPB）的三组分添加剂，可以获得高达5.0V的超高截止电压的优异循环稳定性。在改性电解质中，可以获得优异的离子电导率、两个电极上坚固的界面膜和持久均匀的Li⁺调节能力。

因此，在1mA cm^-2的电流密度下，使用3mAh cm^-2的高镀/剥离容量，锂对称电池表现出超过800小时的稳定循环性能。同时，组装了7.3 Ah级Li[Ni_xCo_yMn_1-x-y]O₂（x=0.83，NCM83）|Li袋式电池，其能量密度高达522 Wh kg^-1，在178次循环中表现出优异的稳定性，初始库仑效率（CE）高达98.0%。

附：英文原文

Title: Long-lifespan 522 Wh kg-1 Lithium Metal Pouch Cell Enabled by Compound Additives Engineering

Author: Tingxuan Tang, Chuang Sun, Yong Li, Minman Tong, Jun Lu, Chao Lai

Issue&Volume: 2024-10-08

Abstract: Matching high-voltage cathodes with lithium metal anodes represents the most viable technological approach for developing secondary batteries with ultra-high energy density exceeding 500 Wh kg-1. Nevertheless, the instability of electrolyte/electrode interface film and commercial electrolytes with cut-off voltage above 4.3 V is still a major concern. Herein, we present that excellent cycling stability with an ultra-high cut-off voltage of up to 5.0 V can be obtained by using three-component additives containing fluoroethylene carbonate (FEC), hexadecyl trimethylammonium chloride (CTAC), and tri(pentafluorophenyl)borane (TPFPB). Excellent ionic conductivity, robust interfacial films on both electrodes, and long-lasting uniform Li+ regulation ability can be obtained in the modifying electrolyte. Consequently, using a high plating/stripping capacity of 3 mAh cm-2 under the current density of 1 mA cm-2, lithium symmetric cells demonstrate stable cycling performance exceeding 800 hours. Meanwhile, the 7.3 Ah-class Li[NixCoyMn1-x-y]O2 (x=0.83, NCM83)| Li pouch cells are assembled, which show a high energy density of 522 Wh kg-1 and present excellent stability over 178 cycles with a high initial coulombic efficiency (CE) of 98.0%.

DOI: 10.1002/anie.202417471

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202417471