Enhanced electrochemical performance of battery‐grade cobalt phosphate via magnetron sputtered copper interfacial layer for potential supercapattery applications

Abstract

The supercapattery has achieved significant prominence for its high specific energy and power: however, still craved for electrodes with high ionic conduction and superior electrochemical performance. The study demonstrates the tuned electrochemical performance of cobalt phosphate via introducing a magnetron sputtered copper interfacial layer. Cobalt phosphate nanomaterials synthesized via the sonochemical approach was utilized as active electrode material. The magnetron sputter technique was employed to deposit copper on current collector (nickel foam). The structural studies and morphological aspects and elemental analysis were analyzed via X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy. Atomic force microscopy (AFM) was performed to scrutinize the surface morphology of magnetron sputtered copper. The cobalt phosphate deposited on copper sputtered nickel foam profits a specific capacity (Qs) of 403.1 C/g (120.9% as compared to bare nickel foam) at 3 mV/s and 348.4 C/g (135.7% as compared with bare nickel foam) at 0.6 A/g in three electrode assembly. This electrode was further utilized in an asymmetric architecture (supercapattery device) that delivers outstanding Qs of 265.2 C/g with excellent Es of 62.6 Wh/kg and Ps of 425 W/kh at 0.5 A/g. The device also delivers an excellent Ps of 7924 W/kg while retaining Es of 11.8 Wh/kg at 7 A/g. Moreover, outstanding capacitive retention of 92.9% was observed after 5000 consecutive charge discharge cycles. In addition, the hybrid performance of the designed supercapattery was also explored via a theoretical methodology. The maximum diffusive and capacitive contribution of 88.81% (at 3 mV/s) and 55.11% (at 100 mV/s) was grasped by the device. To the best of our knowledge, this is the first approach toward the utilization of magnetron sputtered interfacial nanograins layer to tune the electrochemical performance of electrode material for potential supercapattery devices.