Suppressing Sponge-Like Li Deposition via AlN-Modified Substrate for Stable Li Metal Anode

Sponge-like lithium (Li) deposition results in high-surface-area morphology that harmfully accelerates the side reactions between Li and electrolyte, arousing serious safety issues of next high energy density Li metal batteries (LMBs). Herein, we propose a strategy to suppress the sponge-like Li deposition by plating Li metal on aluminum nitride (AlN)-modified substrates. For a practical Li deposition of 4 mAh cm^-2 on a AlN-modified copper (Cu) electrode, the roughness and thickness of the as-deposited Li layer are only ∼10% and ∼50% of those for the Li layer deposited on bare Cu. Only based on the compacted Li deposition layer without any other protective remedies, the AlN-modified Cu electrode could provide a Li cycling life of 5 times longer than that on bare Cu, and an AlN-modified carbon felt was proved as an efficient interlayer to boost the cycling stability of Li||LiFePO₄ batteries. These results demonstrate the high importance of suppressing the sponge-like Li deposition for high energy density LMBs.