# A Lithiophilic Artificial Li3P Interphase with High Li-Ion Conductivity via Solid-State Friction for Lithium Metal Anodes

## TL;DR

This paper introduces a new method to create a stable lithium metal anode using a Li3P interphase, improving battery performance and longevity.

## Contribution

A novel red phosphorus-assisted solid-state friction method is introduced to fabricate a uniform Li3P interphase on lithium metal.

## Key findings

- The Li3P interphase significantly enhances interfacial stability and electrochemical kinetics.
- Symmetric cells with the Li3P interphase achieved over 1000 hours of stable cycling at 1 mA/cm².
- Full cells with Li@P anodes retained 88.9% of their capacity after 550 cycles at 2 C.

## Abstract

Interfacial modification strategies for lithium metal anodes have emerged as a promising method to improve cycling stability, suppress lithium dendrite growth, and increase Coulombic efficiency. However, the reported chemical synthesis methods lead to side reactions and side products, which hinder their electrochemical performance. In this study, we propose a novel and facile red phosphorus-assisted solid-state friction method to in situ fabricate a uniform Li3P interphase directly on the surface of lithium metal. Interestingly, the as-formed artificial Li3P interphase with high ionic conductivity and lithium affinity features significantly enhanced interfacial stability and electrochemical kinetics. The symmetric cells based on Li@P with the Li3P interphase achieved a prolonged lifespan, over 1000 h, at 1 mA/cm2 with low polarization. When paired with a high-loading LiFePO4 cathode (10.5 mg/cm2), the Li@P||LiFePO4 full cell retained 88.9% of its capacity after stable cycling for 550 cycles at 2 C and further demonstrated the excellent performance and stability of the Li@P‖LiCoO2 full pouch cell. This study provides an efficient and scalable strategy for stabilizing lithium metal anodes, expanding new ideas for the development of next-generation high-energy-density batteries.