In-situ SEI reconstruction for fast-charging carbon electrodes toward anode-free lithium metal batteries

Anode-free lithium metal batteries (AFLMBs) offer a promising route to high energy density but suffer from poor reversibility, especially under rapid lithium (Li) plating conditions, due to undesired Li dendrites and unstable solid electrolyte interphase (SEI) formation. Herein, we report an in-situ SEI reconstruction strategy to address the kinetic mismatch on carbon electrodes during fast charging in AFLMBs. During formation cycling, Li₃PO₄ pre-loaded on carbon electrode is in-situ incorporated into the evolving SEI. Combined machine learning-graph neural networks and density functional theory calculations reveal that this integration enriches grain boundaries of inorganic Li species in the SEI. This enrichment substantially reduces the Li⁺ diffusion barrier and lowers the activation energy at the SEI/Li interface, which facilitates the followed interfacial charge transfer. Morphology analysis confirms that the strategy suppresses the formation of irregular, mossy Li deposits, promoting uniform and dense Li plating. Consequently, the prepared carbon electrode (PNCNT) achieves improved Coulombic efficiency and cycle life even at high areal capacities (up to 2.0 mAh cm^–2) and high lithiation current densities (2.0–8.0 mA cm^–2). This work effectively expands the application prospects of carbon electrodes and providing a promising direction for designing fast-charging AFLMBs.