An Ultrafast and Stable Li‐Metal Battery Cycled at −40°C
An Ultrafast and Stable Li‐Metal Battery Cycled at −40°C
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在 40°C 下循环的超快且稳定的锂金属电池
DOI：
10.1002/adfm.202212349
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发表时间：
2022
影响因子：
19
通讯作者：
Hua Wang
中科院分区：
文献类型：
--
作者：
Liwei Cheng;Yingyu Wang;Jie Yang;Mengyao Tang;Chenguang Zhang;Qiaonan Zhu;Sicong Wang;Yuting Li;Pengfei Hu;Hua Wang
锂金属电池（LMB）受到意想不到的锂枝晶生长和不稳定的固体电解质界面（SEI）的影响，特别是在极端条件下，如高倍率和低温（LT）。通过调节电解质的化学性质，实现了高倍率和稳定的LMB。采用弱Li+溶剂2 -甲基四氢呋喃作为电解质溶剂，减轻Li+脱溶剂的动力学障碍。此外，加入高给体数的共溶剂四氢呋喃来改善Li盐的LT溶解度，在保持弱Li+溶剂化效应的同时提高了离子电导率。此外，在接触离子对中出现了丰富的FSI阴离子，促进了稳定富liff SEI的形成。因此，Li||锂电池可以在−40°C下工作在10 mA cm‐2和154 mV的小极化下。同时，在8.0 mA cm - 2下，达到了4000 mAh cm - 2的累积循环容量，达到了LT碱金属对称电池的最高水平。此外，可充电的高倍率和稳定的全电池在- 40°C下实现。这项工作证明了电解质化学在离子转移动力学和SEI的协同调节方面的优势，从而使lmb在低温下实现超快和稳定的可充电。
Li‐metal battery (LMB) suffers from the unexpected Li dendrite growth and unstable solid‐electrolyte interphase (SEI), especially in the extreme conditions, such as high rates and low temperatures (LT). Herein, a high‐rate and stable LT LMB is realized by regulating electrolyte chemistry. A weak Li+‐solvating solvent 2‐methyltetrahydrofuran is used as electrolyte solvent to mitigate the kinetic barrier for Li+de‐solvation. Moreover, a co‐solvent tetrahydrofuran with a high donor number is incorporated to improve the LT solubility of Li salts, achieving an improved ionic conductivity while maintaining the weak Li+‐solvation effect. Furthermore, abundant FSI‐anions in contact‐ion pairs are presented, facilitating the formation of a stable LiF‐enriched SEI. Consequently, the Li||Li battery can be operated at 10 mA cm‐2with a small polarization of 154 mV at −40 °C. Meanwhile, an outstanding cumulative cycling capacity of 4000 mAh cm‐2at 8.0 mA cm‐2is achieved, reaching a record high level in LT alkali metal symmetric batteries. Also, rechargeable high‐rate and stable full batteries are achieved at −40 °C. This work demonstrates the superiority of electrolyte chemistry for synergistic regulation of both ion transfer kinetics and SEI toward ultrafast and stable rechargeable LMBs at LT.