Recent advances on metal sulfides as next-generation electrodes for supercapacitor energy storage: A holistic review

The rapid advancement of energy storage technologies has underscored the critical need for high-performance electrode materials that combine high energy density, power density, and long cycle life. Transition metal sulfides (TMSs) have emerged as next-generation candidates for electrochemical supercapacitor electrodes due to their unique layered structures, high redox activity, and tunable electronic properties. This comprehensive review highlights recent progress in the synthesis, structural design, and electrochemical performance of metal sulfide-based electrodes, with a focus on their application in supercapacitors. We discuss the classification of metal sulfides based on composition, summarize various synthesis methods, and analyze strategies to overcome inherent drawbacks such as limited conductivity and cycling stability. The review also explores the enhancement of TMS properties through compositing with conductive polymers, carbonaceous materials, MXenes, and metal–organic frameworks (MOFs), as well as the role of defect engineering in optimizing electrochemical behavior. Here, we have addressed the current challenges and future perspectives for the scalable production and practical deployment of metal sulfide-based electrodes in advanced energy storage systems, aiming to guide further research and innovation in the field.