Lithium-ion comb—artificial self-regulating lithium-storage film on aluminum anode enabling long cycles of batteries

Al anode can increase battery energy density, but its non-wettability and high Li nucleation hindrance cause uneven Li nucleation to deteriorate the anode structure. Herein, we present a novel in-situ synthesis method for the deposition of molybdenum oxide nanospheres (NMO) onto the surface of Al foil, that is, molybdenum oxide/aluminum (M-Al), which demonstrates a two-stage propulsion effect on Li-ion migration to address the issue at hand. The high wettability and low Li nucleation hindrance of the NMO layer drive the first stage of Li-ion migration. NMO acted as a comb to deliver Li ions uniformly with minor volume expansion. Subsequently, the formation of Li₂O-rich solid electrolyte interphase (SEI) film with exceptional desolvation capability, facilitated by the NMO layer and electrochemically activated M-Al to Li molybdate/aluminum (Li-M-Al), represents the second stage in the advancement of Li−ion migration. The embedding of lithium ions makes molybdenum oxide evolve into lithium molybdate, thereby enabling Mo to regulate the storage of Li ions through the valence state. Hence, the Li nucleation overpotential of M-Al is decreased by 0.32 V, leading to a significant enhancement in the cycling performance of the Li-M-Al||LiFePO₄ (LFP) battery, with a capacity retention rate of 78.5 % after 400 cycles at 1C.