Organophosphorus Hybrid Solid Electrolyte Interphase Layer Based on Li_xPO₄ Enables Uniform Lithium Deposition for High‐Performance Lithium Metal Batteries

Abstract Lithium metal is a promising anode candidate for the next‐generation rechargeable battery system because of its highest specific capacity and lowest potential. However, low Coulombic efficiency (CE) and the formation of Li dendrites during the cycling process seriously hinder its practical application. Here, an organophosphorus hybrid flexible solid electrolyte interphase (SEI) layer is proposed based on a surface chelation strategy using phytic acid (PA) as Li metal surface treatment chemicals. Different from the traditional SEI layer, the polynuclear complex between PA and Li⁺ serves as a “connecter” in this SEI layer, which not only ensures its mechanical flexibility but also improves its lithiophilic property and ionic conductivity. With these advantages, the Li || Cu cells exhibit a high CE of 99.0% over 500 cycles at a current density of 0.5 mA cm⁻². Li || Li symmetrical cells can also maintain a stable Li plating/stripping process over 2500 h at a high current density of 10.0 mA cm⁻². Besides, all Li metal batteries (Li || S, Li || NCM, Li || LFP et al.) based on this strategy exhibit long cycling life and high capacity retention. This surface chelation strategy is believed to offer a new avenue to fabricate a stable and efficient SEI layer for practical application of Li metal batteries.