Hierarchical MoS₂ Sponge with Enhanced Electrochemical Properties for Lithium Storage and Water Splitting

Lithium ion batteries have become an appealing candidate for next-generation energy-storage technologies because of their low cost and high energy density. Molybdenum based layered chalcogenide material is a promising electrode material for future applications in clean energy conversion and storage such as high-performance lithium-ion batteries and electrochemical hydrogen evolution in water splitting. Herein, the fabrication of a unique hierarchical 2D layered MoS₂ sponge nanostructure was demonstrated via facile solvothermal technique. The structural study reveals the existence of hexagonal MoS₂ phase. The obtained MoS₂ was sponge-like, with uniform distribution of voids and wall thicknesses, analyzed by FESEM and TEM. In Li-ion storage testing, the half-cell delivered the specific capacity of 1265 and 1256 mAh g^-1 at 50 mAg^-1 and 1172 and 1161 mAh g^-1 at 200 mA g^-1 for the first discharge and charge with columbic efficiency 99.3 and 99.0 %, respectively. The MoS₂ sponge structure possesses the over-potential (ɳ) of 263 mV at a current density of 10 mA/cm². A Tafel slope of ≈ 134 mV dec^-1 is measured for a MoS₂ sponge electrode could arise from various reaction pathways of hydrogen evolution. The sponge MoS₂ structure shows the excellent cyclic stability performance could be attributed to layered porous MoS₂ sponge nanostructure.