Bio-inspired synthesis of transition-metal oxide hybrid ultrathin nanosheets for enhancing the cycling stability in lithium-ion batteries

Constructing two-dimensional (2D) structures for transition-metal oxides (TMOs) can optimize their electronic structures and enable high specific surface areas, thereby offering routes to enhancing the performance of TMOs in energy storage and conversion. However, most 2D TMOs, e.g., Fe₂O₃, remain so far synthetically challenging due to their intrinsic non-layered structures. Herein, inspired by the mechanism of biomineralization, we report the synthesis of CuO/Fe₂O₃ hybrid ultrathin nanosheets by using polyvinylpyrrolidone-decorated CuO nanosheets as growth modifiers to modulate the hydrolysis process of Fe²⁺. The formulated “absorption-and-crystallization” two-step formation processes of such 2D hybrid structures accorded well with the biomineralization scheme in nature. Combining the in-situ transmission electron microscopy (TEM) study, theoretical calculation, and control experiments, we validated that the large density of 2D/2D interfaces enabled by this bio-inspired synthesis process can overcome the self-stacking phenomenon during lithium-ion battery cycling, leading to their high operation stability. This work emphasizes the bio-inspired synthesis of 2D TMOs as a promising pathway toward material design and performance optimization.