Reprogramming spatial ion–solvent organization in the inner Helmholtz plane for high-energy-density and long-life lithium metal batteries

Abstract

Lithium metal anodes are promising for next-generation energy storage owing to their high theoretical capacity and low redox potential. However, the native solid electrolyte interphase (SEI) is often compositionally heterogeneous and prone to damage, leading to continuous SEI growth, ultimately hindering uniform lithium-ion deposition. Here, we demonstrate an inner Helmholtz plane (IHP) engineering strategy by constructing a finely controlled spatial-organization-regulating Li2O interfacial layer on the lithium surface. Li2O reprograms ion–solvent organization within the IHP, thereby redirecting the reaction pathways and spatial evolution of SEI formation. Consequently, a thinner SEI enriched in Li2O and LiF is formed on the Li surface. Owing to this design, a high-energy-density pouch cell (431.1 Wh kg−1) can stably cycle for 500 cycles with a capacity retention of 80.7%. This unique insight—modulating electrolyte molecular behavior through an artificial surface functional layer—offers a novel strategy toward dendrite-free lithium deposition and long-term cycling stability.