Design Principle of Disordered Rocksalt Type Overlithiated Anode for High Energy Density Batteries

Abstract

Rechargeable lithium-ion batteries with high energy density and fast-charging capability are vital for commercial application. Disordered rocksalt (DRX) materials with a cation/anion ratio greater than one, achieved through additional lithium insertion, have emerged as promising high-rate anode candidates. Inspired by the previously reported Li3+xV2O5 (0≤x≤2) anode, a comprehensive search was conducted for all potential redox centers using high-throughput density functional theory (DFT) computations. This study examined 23 redox centers in a prototype formula Li3+xV2O5 (0≤x≤2) with the DRX structure, analyzing aspects such as voltage curve, theoretical capacity, energy density, phase stability, electronic conductivity, and volumetric change during cycling. Promising candidates were identified with redox centers including V, Cr, Nb, Mn, and Fe, marking them as potential anode materials. Additionally, this research revealed the origin of the low voltage in DRX anodes and proposed a method to optimize the average voltage by tuning the relative energies among structures with varying lithium contents. This work provides compositional design principles for new promising DRX anode of LIBs with high energy density, fast-charging capability, and good cycling stability.