A Prelithiation Separator for Compensating the Initial Capacity Loss of Lithium-Ion Batteries
Zhixiang Rao, Jingyi Wu, Bin He, Weilun Chen, Hua Wang, Qiuyun Fu, Yunhui Huang
Abstract
Lithium loss during the initial charge process inevitably reduces the capacity and energy density of lithium-ion batteries. Cathode additives are favored with respect to their controllable prelithiation degree and scalable application; however, the insulating nature of their delithiation products retards electrode reaction kinetics in subsequent cycles. Herein, we propose a prelithiation separator by modifying a commercial separator with a Li2S/Co nanocomposite to compensate for the initial capacity loss. The Li2S/Co coating layer extracts active lithium ion during the charge process and shows a delithiation capacity of 993 mA h g–1. When paired with a LiFePO4|graphite full cell, the reversible capacity is increased from 112.6 to 150.3 mA h g–1, leading to a 29.5% boost in the energy density. The as-prepared pouch cell also demonstrates a stable cycling performance. The excellent electrochemical performance and the scalable production of the prelithiation separator reveal its great potential in lithium-ion battery industry application.