N, P-doped graphite/LiMn₂O₄ hybrid electrode for high-performance all-climate dual-ion batteries

Conventional lithium-ion batteries (LIBs) are nearing their theoretical capacity limit, and there is an urgent need to develop energy storage devices with higher energy densities and cycling stabilities. In this work, a hybrid electrode design, which combines the traditional "rocking chair" mechanism and "anion intercalation" mechanism to improve energy density is reported. The hybrid electrode is composed of LiMn₂O₄ and N,P-doped graphite (NPG) to use both anion and cation storage mechanisms. This design enhances the electrochemical potential windows and the energy density of the fabricated cell. Electrochemical results show that the fabricated cell not only shows a 44.1 % higher capacity than conventional LIBs. It displays a stable cycle life across a wide climate temperature range from - 20 to 25 °C, with a capacity retention rate of 86 % after 600 cycles at 100 mA g^-1. This study demonstrates the critical role of doping graphite with N and P to improve the electrochemical performance of graphite in deep charge/discharge, providing a valuable strategy for developing cathode materials in dual-ion batteries.