Planar Li deposition and dissolution enable practical anode-free pouch cells.

Abstract

Anode-free lithium metal batteries (AFLMBs), which are manufactured without anode active material, offer great potential for high-energy-density, low-cost energy storage. However, AFLMBs face a long-standing challenge of short lifespan because of the harsh conditions of lacking excess Li resource and an anode host^1-8. This issue is associated with uneven Li deposition and dissolution, rooted in the micro-heterogeneity and mechanical fragility of solid electrolyte interphase (SEI)⁹. Here we report a practical 500 Wh kg^-1-level AFLMB with enhanced lifespan, achieved using a crossover-coupled electrolyte. The electrolyte triggers crossover-coupled interfacial reactions that generate a B-F-based polymer-rich SEI at the anode while suppressing gas evolution at the cathode. The resulting SEI exhibits sub-nanometre homogeneity, high flexibility and rapid Li-ion transport, and it spontaneously develops a self-adaptive mesh-film structure that ensures uniform ion flux and large-volume-change accommodation, thereby realizing reversible planar Li deposition and dissolution of 5.6 mAh cm^-2. Consequently, a 2.7 Ah AFLMB (508 Wh kg^-1, 1,668 Wh l^-1) without any host-material coating demonstrates stable cycling for 100 cycles at 100% depth of discharge (DOD) and 250 cycles at 80% DOD, with 80% capacity retention and a high-power output of 2,650 W kg^-1 at 96 Wh kg^-1. These findings establish crossover-coupled interphase chemistry and address the inherent structural instability of host-free electrodes, advancing the practical implementation of AFLMBs.