Self-templated sacrificial strategy to construct nanorod array-like Co₉S₈ for high-performance asymmetric supercapacitors

As the global demand for energy continues to grow and environmental issues become increasingly severe, the exploration of efficient and sustainable energy storage solutions has become an urgent priority. This research showcases the successful fabrication of uniformly dispersed Co₉S₈ nanorod arrays (designated as Co₉S₈/NF) intimately integrated onto nickel foam (NF) substrates, leveraging an innovative two-step hydrothermal method that incorporates a self-templated sacrificial approach. This methodology ensures the in situ growth of the nanorods, markedly elevating the specific capacity and conferring superior long-term electrochemical stability upon the composite material. The distinctive nanorod morphology not only furnishes an abundance of active sites for charge storage but also facilitates rapid ion diffusion and transport, thereby boosting performance. Consequently, the Co₉S₈/NF electrode demonstrates an impressive specific capacity of 1528.4 C g⁻¹ at 1 A g⁻¹, accompanied by remarkable cycling stability, retaining 81.2% of its initial capacitance after 10,000 cycles. Furthermore, when assembled into an asymmetric supercapacitor (ASC), this system exhibits a commendable energy density of 155.5 Wh kg⁻¹ at a power density of 1600 W kg⁻¹, underscoring its potential for practical applications. Significantly, following a stringent stability assessment encompassing 10,000 cycles, the ASC demonstrates an outstanding retention of current at 91.4%, underscoring the material system’s exceptional endurance and dependability.