In situ synthesis and electrochemical properties of Fe/Li2O as a high-capacity cathode prelithiation additive for lithium ion batteries

Abstract

The irreversible capacity loss in the first cycle significantly reduces the specific capacity of lithium ion batteries. Cathode prelithiation is a common method to alleviate this problem. Here, Fe/Li2O were successfully prepared by in situ solid phase reaction method. Fe/Li2O as a cathode prelithiation additive has a high prelithiation specific capacity of 447.3 mAh g-1 during charging, and the first charge capacity of LiNi0.6Co0.2Mn0.2O2 with 7.5% Fe/Li2O additive could be enhanced by 9.1% and its cycling stability was improved from 86.9% to 90.2% after 70 cycles. The cathode prelithiation additive remarkably enhanced the content of active lithium during the initial delithiation process, contributing the formation of solid electrolyte interphase on the anode surface and better cycling stability. This easy-operating cathode prelithiation method could obtain evident effect of prelithiation and had good compatibility with existing lithium ion batteries.