Expanding the ReS2 Interlayer Promises High-Performance Potassium-Ion Storage

Improving the electrochemical kinetics and the intrinsic poor conductivity of transition metal dichalcogenide (TMD) electrodes is meaningful for developing next-generation energy storage systems. As one of the most promising TMD anode materials, ReS2 shows attractive performance in potassium-ion batteries (PIBs). To overcome the poor kinetic ion diffusion and limited cycling stability of the ReS2-based electrode, herein, the interlayer distance expanding strategy was employed, and reduced graphene oxide (rGO) was introduced into ReS2. Few-layered ReS2 nanosheets were grown on the surface of the rGO with expanded interlayer distance. The prepared ReS2 nanosheets show an expanded distance (similar to 0.77 nm). The synthesized EI-ReS2@rGO composites were used in PIBs as anode materials. The K-ion storage mechanism of the ReS2-based anode was investigated by in situ X-ray diffraction (XRD) technology, which shows the intercalation and conversion types. The EI-ReS2@rGO nanocomposites show high specific capacities of 432.5, 316.5, and 241 mAh g(-1) under 0.05, 0.2, and 1.0 A g(-1) current densities and exhibit excellent reversibility at 1.0 A g(-1). Overall, this strategy, which finely tunes the local chemistry and orbital hybridization for high-performance PIBs, will open up a new field for other materials.