The Electrolysis of Anti‐Perovskite Li2OHCl for Prelithiation of High‐Energy‐Density Batteries

Abstract

AbstractAnti‐perovskite type Li2OHCl was previously studied as a solid‐state Li+ conductor. Here, we report that the Li2OHCl can be electrolyzed at 3.3 V or 4.0 V, with the creation of O2/HCl gases and the release of 2 equiv. Li+ via two different decomposition routes, depending on the acidity of electrolyte. In the electrolyte with trace acid, the Li2OHCl is oxidized at a constant voltage of 3.3 V. In neutral electrolyte, the oxidization of Li2OHCl starts at 4.0 V, but the produced HCl will increase the acidity of electrolyte and lead to a voltage drop to 3.3 V for the electrolysis of Li2OHCl. The electrolysis of Li2OHCl delivers a lithium releasing capacity as high as 810 mAh g−1, with an equivalent Li‐deposition or Li‐intercalation on anode, making it a promising candidate as a Li reservoir for prelithiation of anode. Using Li2OHCl as the lithium source, silicon‐carbon (Si@C) composite anode can be effectively prelithiated. The full cells composed of LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode and prelithiated Si@C anode exhibited increased capacities with the increment of prelithiation dosages.