Zhang Weili, Lu Yang, Wan Lei, Zhou Pan, Xia Yingchun, Yan Shuaishuai, Chen Xiaoxia, Zhou Hangyu, Dong Hao, Liu Kai
Department of Chemical Engineering, Tsinghua University, Beijing, China.
Nat Commun. 2022 Apr 19;13(1):2029. doi: 10.1038/s41467-022-29761-z.
In electrochemical devices, such as batteries, traditional electric double layer (EDL) theory holds that cations in the cathode/electrolyte interface will be repelled during charging, leaving a large amount of free solvents. This promotes the continuous anodic decomposition of the electrolyte, leading to a limited operation voltage and cycle life of the devices. In this work, we design a new EDL structure with adaptive and passivating properties. It is enabled by adding functional anionic additives in the electrolyte, which can selectively bind with cations and free solvents, forming unique cation-rich and branch-chain like supramolecular polymer structures with high electrochemical stability in the EDL inner layer. Due to this design, the anodic decomposition of ether-based electrolytes is significantly suppressed in the high voltage cathodes and the battery shows outstanding performances such as super-fast charging/discharging and ultra-low temperature applications, which is extremely hard in conventional electrolyte design principle. This unconventional EDL structure breaks the inherent perception of the classical EDL rearrangement mechanism and greatly improve electrochemical performances of the device.
在诸如电池等电化学装置中，传统的双电层（EDL）理论认为，在充电过程中，阴极/电解质界面处的阳离子会被排斥，从而留下大量的游离溶剂。这促进了电解质的持续阳极分解，导致装置的工作电压和循环寿命受限。在这项工作中，我们设计了一种具有自适应和钝化特性的新型双电层结构。它是通过在电解质中添加功能性阴离子添加剂来实现的，这些添加剂可以选择性地与阳离子和游离溶剂结合，在双电层内层形成具有高电化学稳定性的独特的富阳离子和分支链状超分子聚合物结构。由于这种设计，醚基电解质在高压阴极中的阳极分解得到了显著抑制，并且电池展现出诸如超快充电/放电和超低温应用等优异性能，而这在传统电解质设计原理中是极其困难的。这种非常规的双电层结构打破了经典双电层重排机制的固有认知，并极大地提高了装置的电化学性能。
