Unveiling the redox electrochemical kinetics of interconnected wrinkled microspheres of binary CuSe/NiSe as battery-type electrode for advanced supercapatteries.

Developing a rational design of nanoarchitechtures with excellent electrochemical behaviors is an ultimate and unique strategy to enhance the redox electrokinetics of battery-type electrode materials. Herein, we demonstrate a hierarchical composite comprising interconnected wrinkled micro-solid sphere (ICWMS)-like binary copper selenide/nickel selenide over nickel foam (CuSe/NiSe/NF) prepared via a wet chemical synthetic protocol and utilized as an effective positrode for improved supercapaterry performance. The binary CuSe/NiSe/NF electrode considerably improved the electroactive surface area and facilitated ultrafast redox electrochemistry in an alkaline electrolyte medium. Remarkably, the binary CuSe/NiSe/NF electrode afforded the highest specific capacity of 368 ± 1C/g at 1 A/g greater than that of pristine single selenide electrodes (CuSe and NiSe) in a three-electrode setup which might be attributed to its large surface area, synergism between Ni and Cu, and specific morphology. Moreover, a coin cell supercapattery with the binary CuSe/NiSe/NF positrode and a porous activated carbon-on-nickel-foam negatrode was constructed, which exhibited excellent energy-storage characteristics in terms of capacity (87.5 ± 1 mAh/g), specific energy (39.3 Wh kg), specific power (450 W kg), and capacity retention (91.8 %). This simple fabrication approach of hierarchically designed CuSe/NiSe/NF paves the way for utilizing it as the promising positrode for high-performance supercapattery.