Ni-Co-A (A= O, S, P) nanosheets for all-solid-state hybrid supercapacitors: Anion substitution unlocks high energy and power density
Roshini Arulraj, Shilpi Sengupta, Manab Kundu
Abstract
• Phosphorus-substituted Ni/Co nanosheets (NCP) exhibit superior electrochemical performance. • NCP nanosheets achieved 1446C g −1 at 20 A g −1 with a cycle stability of 90.54 % at 40 A g −1 after 10,000 cycles. • NCP-based hybrid supercapacitors operate at 1.7 V with a specific capacity of 256.4C g −1 at 2 A g −1 . • The NCP HSCs deliver 121.8 Wh kg −1 at a power density of 3.414 kW kg −1 . • This work establishes NCP electrodes as a highly effective solution for high-power applications. The global shift toward sustainable energy solutions drives the need for advanced energy storage technologies. This study investigates Ni/Co-based nanosheets with anion substitution (A = O, S, P) as high-performance electrode materials for hybrid supercapacitors (HSCs). We significantly enhanced the electrochemical properties by fine-tuning the electrode materials through substituting anions, offering a promising alternative to traditional battery-type materials. Phosphorus-substituted Ni/Co nanosheets (NCP) exhibit remarkable electrical conductivity, high redox activity, and structural stability due to their synergistic bimetallic composition and optimized nanosheet morphology. These electrodes, when integrated into all-solid-state hybrid supercapacitors, demonstrated outstanding performance with an extended working voltage of 1.7 V, a specific capacity of 256.4C g −1 at 2 A/g, and energy and power densities of 121.8 Wh kg −1 and 3.414 kW kg −1 , respectively. The NCP-based HSCs also displayed excellent long-term cycling stability and charge/discharge characteristics, even at high current densities. These results highlight the transformative potential of NCP nanosheets for next-generation energy storage systems, paving the way for efficient and sustainable solutions in high-power and energy-intensive applications.