In-Situ Synthesis of Petal-Like MoO2@MoN/NF Heterojunction As Both an Advanced Binder-Free Anode and an Electrocatalyst for Lithium Ion Batteries and Water Splitting

The design and synthesis of a heterostructure as well as binder-free electrodes or electrocatalysts with a porous nanostructure for enhancing electrochemical performance of lithium ion batteries and water splitting are still significant challenges to scientists. Here, for the first time, an in-situ synthesis of the porous petal-like MoN nanolayer-coated MoO2 heterojunction (MoO2@MoN) on commercial nickel foam (NF) by a localized nitrided transformation method as both a binder-free electrode for LIBs and an electrocatalyst for water splitting was performed. The in-situ formation of the MoN nanolayer could create a MoO2@MoN heterostructure, therefore enhancing the electronic conductivity and the electron/ion transfer. The XRD and XPS measurements confirmed the wonderful reversibility of the MoN layer during lithiation/delithiation cycling, which effectively promoted the long-life cycling performance (1190.1 mA h g–1 after 500 cycles at the current density of 0.5 A g–1). Meanwhile, the MoO2@MoN/NF/LiFePO4 full cell displayed stable capacity after 100 cycles. Moreover, the product also showed the improved electrocatalytic activity for hydrogen evolution and oxygen evolution. The excellent results suggest that our work opens a simple in-situ heterojunction formation pathway for the synthesis of other multifunctional materials applied in energy conversion and storage.