Modified lithium metal anode via anion-planting protection mechanisms for dendrite-free long-life lithium metal batteries

Abstract

Lithium metal anodes (LMAs) are being researched to enhance their potential as ideal candidates for high-energy-density rechargeable batteries. However, an unstable solid–electrolyte interphase (SEI) layer and dendrite formation severely hinder their practical operations due to poor coulombic efficiency (CE) and potential security risks. Herein, an artificial SEI layer with various inorganic species was constructed via a strategy involving pre-planting various salt anions on the LMA. The as-prepared layer with multifunctional properties could stabilize liquid–electrode interfaces and proactively regulate even distribution and facilitate the homogeneous diffusion of the ion flux. Moreover, the anion-release behavior of this layer would be an additional attribute that could compensate for the anion consumption during cycling. As a result, the performance of modified LMAs could be significantly improved via this artificial SEI. Li–Cu cells provided CEs of above 98% among a range of current densities with long lifespans, and the symmetric cells showed stable cycling for over 1800 h at 1 mA cm⁻². In practice, an assembled LiFePO₄/Li cell displayed excellent cyclability of over 1000 cycles with high CEs at 2C. This strategy via., anions-planting protection mechanisms sheds light on tuning robust artificial SEI layers and can offer a fresh perspective to guide the design of high-performance LMAs.