Hydrazine hydrate reduction-induced oxygen vacancy formation in Co₃O₄ porous nanosheets to optimize the electrochemical lithium storage

Co₃O₄ materials have been widely studied as lithium-ion batteries (LIBs) anode due to the high theoretical specific capacity. However, the poor inherent conductivity and large volume change are the main limitations. To address these issues, we propose a mild liquid-phase reduction strategy by using hydrazine hydrate to modify the Co₃O₄ porous nanosheet electrodes. Through controlling the hydrazine hydrate volume, the generation of oxygen vacancies in the Co₃O₄ electrodes can be adjusted. When tested as the anodes for LIB, the optimized electrode delivers a reversible capacity of 1036.7 mAh g⁻¹ after 55 cycles at a current density of 0.5 A g⁻¹, and a specific capacity of 434.6 mAh g⁻¹ at a higher current density of 2 A g⁻¹. The improved electrochemical performance is attributed to the porous structure of the nanosheet and the presence of oxygen vacancies.