Planar lithium deposition/dissolution enabling practical 500 Wh kg–1 anode-free pouch cells

Anode-free lithium metal batteries (AFLMBs), characterized by the absence of anode active materials during manufacturing, offer great potential for high-energy-density, low-cost energy storage. However, AFLMBs face a long-standing challenge of short lifespan due to the harsh conditions of lacking excess lithium and an anode host. This issue is associated with uneven lithium deposition/dissolution, rooted in the micro-inhomogeneity and fragility of solid electrolyte interphase (SEI) on the lithium metal surface. Here, we present a practical 500 Wh kg–1-level AFLMB design with enhanced lifespan, achieved using an electrolyte of 1.6 M lithium difluoro(oxalate)borate in N,N-Dimethyltrifluoroacetamide solvent. The electrolyte-derived B-F-based polymer-rich SEI exhibits sub-nanometer homogeneity, high flexibility, and fast Li-ion conductivity, which spontaneously evolves a self-adaptive mesh-film structure that ensures uniform ion flux and large-volume-change accommodation, thereby realizing reversible planar lithium-orientated deposition/dissolution of 5.6 mAh cm–2. Consequently, a 2.7 Ah AFLMB (508 Wh kg–1, 1668 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 an unprecedentedly high-power output of 2650 W kg–1 at 96 Wh kg–1. Our findings address the inherent structural instability of host-free electrodes, advancing the practical implementation of AFLMBs.