With the continuous advancement in the dual-carbon strategy, the upswell in the demand for renewable energy sources has motivated extensive research on the development of novel energy storage technologies. As a new type of energy storage device, carbon-based redox-enhanced supercapacitors (RE-SCs) are designed by employing soluble redox electrolytes into the existing devices, exploiting the merits of the diffusion-controlled faradaic process of the redox electrolyte at the surface of carbon electrodes, thus leading to improved energy density without the cost of power density. During the past years, great progress has been made in the design of novel redox electrolytes and the configuration of new devices. However, the development of these systems is plagued by severe self-discharge. Herein, a comprehensive picture of the fundamentals, together with a discussion and outline of the challenges and future perspectives of RE-SCs, are provided. We highlight the impacts of redox electrolytes on capacitance, energy density, and power output. Notably, the self-discharge behavior owing to the introduction of redox electrolyte and its mechanism are also discussed, followed by a summary of the strategies from materials to system optimization. Furthermore, possible directions for future research are discussed.

Presently, interfacial solar water evaporation (ISWE) is now injecting new vitality into the field of water remediation. However, during the ISWE process, the nonvolatile pollutants might be concentrated in residual water, and further contaminate the environment. Preparing advanced photothermal materials is in need to get comprehensive purification of various pollutants in residual water. Herein, we report a facile laser thermal method to prepare Cu_2−xS/sulfur/reduced graphene oxide (Cu_2−xS/S/rGO) nanocomposites for realizing all-round residual water remediation during the ISWE process. The as-prepared Cu_2−xS/S/rGO nanocomposites demonstrated excellent photothermal and photocatalytic properties. Through blending with GO nanosheets having excellent adsorption capacity, the synergetic effect of photothermal, photocatalytic, and adsorption properties resulted in highly efficient purification of rhodamine B, bacterial, and heavy metal ions in residual water during the ISWE process. The experimental results also showed that, increasing solar light intensity can promote the residual water remediation, but ultrafast water evaporation under high light intensity may deteriorate the purifying effect. This report may pave a new way to prepare multifunctional materials for water remediation through the ISWE technology.