Controllable oxygen-incorporated interlayer-expanded ReS2 nanosheets deposited on hollow mesoporous carbon spheres for improved redox kinetics of Li-ion storage

Two-dimensional (2D) ReS2 is considered as a promising energy storage material owing to its high theoretical capacity and extremely weak van der Waals forces. However, the use of 2D ReS2 is limited by its low electrical conductivity, slow ion diffusion, and huge volume expansion. Herein, we demonstrate oxygen incorporation and interlayer expansion of ReS2 nanosheets deposited on hollow mesoporous carbon spheres. The oxygen content of 2D ReS2 is controlled by varying the reaction solvents and temperatures and thus, its interlayer spacing is expanded, which facilitates the redox kinetics by means of the improved electronic conductivity and rapid ion diffusion as demonstrated by computational calculation and electrochemical characterization. Moreover, a hollow mesoporous core/shell hybrid architecture contributes to a large accessible area and porous channels. The as-optimized hybrid electrodes with expanded interlayers and oxygen content achieve higher capacity and better rate and cycling capabilities than other samples. Therefore, this chemical strategy highlights the importance of controlling the interlayer spacing and chemistry of ReS2 to overcome the kinetic and stability limitations of 2D energy storage nanomaterials.