Porous hexagonal Mn5O8 nanosheets as fast-charging anode materials for lithium-ion batteries

Among various metal oxide nanomaterials, manganese oxides, which can exist in different structures and valence states, are considered highly promising anode materials for lithium-ion batteries (LIBs). However, conventional manganese oxides, such as MnO and MnO2, face significant challenges during cycling process. Specifically, poor electronic conductivity and large volume changes result in low specific capacity during high current charging and discharging, as well as poor fast-charging performance. This work presents an approach to synthesizing porous hexagonal Mn5O8 nanosheets via hydrothermal and annealing methods and applies them as anode materials for LIBs. The Mn5O8 nanomaterials exhibit a thin plate morphology, which effectively reduces the distance for ion/electron transmission and mitigates the phenomenon of volume expansion. Additionally, the large pore size of Mn5O8 results in abundant interlayer and intralayer defects, which further increase the rate of ion transmission. These unique characteristics enable Mn5O8 to demonstrate excellent electrochemical performance (938.7 mAh·g−1 after 100 cycles at 100 mA·g−1) and fast charging performance (675.7 mAh·g−1 after 1000 cycles at 3000 mA·g−1), suggesting that Mn5O8 nanosheets have the potential to be an ideal fast-charging anode material for LIBs.