Li6Zn0.5Co0.5O4 with high oxygen oxidation reaction activity as a cathode pre-lithiation material for lithium-ion batteries

Abstract

Antifluorite hyper-lithiated metal oxides have the ability to release numerous lithium ions to compensate for active lithium loss (ALL) through a potential oxygen oxidation reaction (OOR). Nevertheless, developing antifluorite hyper-lithiated metal oxides with high specific capacity and significant OOR is a challenge. Here we construct a novel antifluorite dual metal oxide pre-lithiation material (Li₆Zn_0.5Co_0.5O₄) with a high charge specific capacity of 802.7 mAh g⁻¹ below 4.5 V. The weakened chemical bond and energy band rearrangement through Co²⁺ substitution in the Li₆ZnO₄ framework stimulate the OOR activity. However, it suffers from the inevitable structural degradation upon storage in air, which needs to be addressed. Finally, by coupling the pre-lithiation layer, the NCM811||Si/C full cell achieves higher reversible capacity and better cycle life. This study provides a promising strategy to design hyper-lithiated metal oxides with irreversible OOR by simply introducing transition metal ions capable of weakening the chemical bond and elevating the Fermi energy level into the antifluorite framework.