CuWO4: A promising multifunctional electrode material for energy storage as in redox active solid-state asymmetric supercapacitor and an electrocatalyst for energy conversion in methanol electro-oxidation

Abstract

• CuWO 4 has been prepared by quick co-precipitation route within 20 min. • ASC device shows specific capacity of 103 mAh g −1 at 1 A g −1 . • ASC device shows retention of 119.4% of initial capacity after 5000 cycles. • ASC device exhibits energy density of 103 Wh kg −1 at power density of 0.95 kW kg −1 . • For methanol oxidation, the CuWO 4 electrode exhibits 38 mA cm −2 at 0.5 V. This article reports the formation the multifunctional CuWO 4 nanoparticles towards the application of gel electrolyte-based supercapacitor and methanol electro-oxidation. The CuWO 4 nanoparticles were synthesized by a quick chemical co-precipitation route within 20 min. The hydrated precursor was treated at 600 °C for 2 h to convert in to final CuWO 4 products. Structural features of the prepared CuWO 4 were investigated by means of X-ray diffraction, electron microscopies, Fourier transform infrared spectroscopy, Raman and X-ray photoelectron spectroscopy. The CuWO 4 electrode exhibits the specific capacity of 415 mAh g −1 at a current density of 2 A g −1 in three electrode configurations in 1 M Na 2 SO 4 and 3 mM KI mixed electrolyte. The electrode shows retention of 86.1% of its initial specific capacity after 10,000 galvanostatic charge–discharge cycles at 30 A g −1 . An asymmetric solid-state device was assembled by sandwiching the PVA-Na 2 SO 4 and 3 mM KI gel electrolyte in between the CuWO 4 nanoparticle and activated carbon electrodes. The device shows the specific capacity of 103 mAh g −1 at a current density of 1 A g −1 and device shows the retention of 93.4% after 5000 galvanostatic charge–discharge cycles at 7 A g −1 . The hybrid device exhibits energy density of 103 Wh kg −1 at power density of 0.95 kW kg −1 . In electro-catalysis of methanol, the CuWO 4 electrode exhibits the high current density of 38 mA cm −2 at 0.5 V and onset potential achieved as 0.38 V in mixed solution of 1 M KOH and 0.5 M methanol.