Y. Zhang †, M.Z. Sun †, W.K. Zheng †, B.T. Yang, T. Ying, L. Mei, R.X. Yan, H.L. Hu, G.Z. Fang, B.L. Huang *, Z.-S. Wu * and Z.Y. Zeng *

Small, 2025, accepted.

The rising need for efficient energy storage has sparked interest in high-performance supercapacitors. However, their low energy density is a significant drawback. Two-dimensional (2D) transition metal dichalcogenides (TMDs) like MoS2 and WS2 are promising for electrodes due to their adjustable surface chemistry and electronic properties. However, MoS2 and WS2 are still facing challenges including phase instability, limited interlayer accessibility, and poor conductivity in ambient conditions. Here, we present a rapid and controllable strategy for the covalent functionalization of MoS2 and WS2 nanosheets via a "click"-type Michael addition reaction with maleimide derivatives. This approach increases interlayer spacing by more than 1.5 times and enhances electrical conductivity by over threefold, thereby exceptionally improving charge transport and ion diffusion. The functionalized membranes deliver outstanding electrochemical performance, including a volumetric capacitance of up to 164 F cm-3 and capacitance retention exceeding 92% after 10,000 cycles, which are 30-fold increases when comparing with their pristine counterparts. This work offers a robust platform for engineering high-performance TMD-based electrodes and provides a viable route toward next-generation high-performance flexible energy storage devices.