An ultra-low concentration electrolyte with fluorine-free bulky anions for stable potassium metal batteries  

作　　者：Qinguang Liu Mei Geng Ting Yu Li Zhang Changdong Wu Jie Liu Shulin Zhao Qingxin Yang Robin Song Jingjuan Ye Fenfen Wang Yuping Wu Dengji Xiao Yuhui Chen 

机构地区：[1]State Key Laboratory of Materials-Oriented Chemical Engineering,and School of Energy Science and Engineering,Nanjing Tech University,Nanjing 211816,China [2]Jiangsu Sunpower Co.,Ltd.Taixing 225411,China

出　　处：《Nano Research》2023年第6期8290-8296,共7页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.21975124 and 52173173);supported by 21C Innovation Laboratory,Contemporary Amperex Technology Ltd(No.21C-OP-202008).

摘　　要：Potassium metal battery is a promising alternative to Li-ion battery for large-scale energy storage due to the abundant potassium resources and high energy density.However,it suffers from rapid capacity fading and safety issues due to the uncontrolled dendrite growth.Herein,we design a fluorine-free ultra-low concentration electrolyte(ULCE)with the super bulky[BPh_(4)]^(−) anions for stable potassium metal battery.In this special electrolyte,the migration rate of K+in the electrolyte is about six times faster than that of the[BPh_(4)]^(−) anions because of the super bulky structure of the[BPh_(4)]^(−) anions,thus resulting in a high K^(+)transference number of 0.76.This high transference number can effectively make up for the deficiency of K^(+)in ULCE for ensuring the normal operation of the potassium metal battery.In addition,the improved transference number can also promote the uniform distribution of K^(+)flux on the surface of the K metal anode,resulting in uniform K deposition.As a result,this electrolyte achieves a high K plating/stripping Coulombic efficiency of 92.6%over 200 cycles and a stable discharging/charging for 100 cycles under the full battery configuration(K used as the anode and perylene-3,4,9,10-tetracarboxylic dianhydride used as the cathode).

关 键 词：potassium metal batteries ultra-low concentration electrolyte high transference number 

分 类 号：TM912[电气工程—电力电子与电力传动]