A lightweight, Li supplementary and lithiophilic interface enables anode-less lithium metal battery prototyping

Abstract

Lithium metal batteries (LMBs), while offering exceptional energy density for next-generation energy storage, face inherent challenges such as dendrite growth, non-uniform nucleation, and dynamic interfacial instability that hinder their practical deployment. Herein, a lightweight (0.39 mg cm⁻²), Li source supplementary and moisture-proof interfacial layer is developed to enable anode-less LMB prototyping. This layer is composed of high-entropy alloys (HEAs) and an in situ grown carbon nanotube (CNT) scaffold, modified with thermally alloyed Li₂₂Sn₅ blended with a hydrophobic ethylene-vinyl acetate (EVA) copolymer. The Li₂₂Sn₅@EVA composite acts as a moisture-proof cation reservoir, while the HEAs and CNTs synergistically regulate lithium-ion flux and nucleation, promoting uniform lithium deposition and enhancing mechanical stability. The integrated layer (HEA@CNT/Li₂₂Sn₅@EVA) enables dendrite-free lithium plating at a high areal capacity of 6 mA h cm⁻² and stable cycling in symmetric cells at 2 mA cm⁻², even under a 75% depth of discharge. When paired with a LiFePO₄ cathode (LFP, 25.53 mg cm⁻²) in a 145 mA h pouch cell, the prototype achieves a gravimetric energy density of 325.2 W h kg⁻¹ and a power output of 603.5 W kg⁻¹ at an ultralow N/P ratio of 0.22. This interfacial design is broadly applicable to anode-free alkali metal batteries, offering a pathway toward high-energy and high-power energy storage solutions.