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.