Mesoporous silver-cobalt-phosphate nanostructures synthesized via hydrothermal and solid-state reaction for supercapattery devices

In this work, we are reporting binary silver cobalt phosphate for high-performance supercapattery devices. The desired material was synthesized through two different techniques, single-step hydrothermal and two-step solid-state reaction. Surface morphology, crystallinity, elemental analysis, elemental composition, and porosity of the materials have been probed through the results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The electrochemical potential of synthesized materials was examined in three-electrode assembly by performing cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 M KOH electrolyte. From the obtained results, it was concluded that material synthesized through the hydrothermal technique has a rod- and sphere-like morphologies with specific surface area of similar to 41328 cm(2)/g and a pore size of similar to 10.28 nm. Furthermore, the theoretical calculations were performed to confirm the electrode material's nature for storing charges, and the results reveal that the material is of battery graded nature. Finally, this material has been utilized for the assembling of a supercapattery device by coupling it with carbon nanotubes (CNT) and placing filter paper as a separator between them. The device performance had been examined with CV, GCD, EIS, and stability testing in 1 M KOH electrolyte. This device delivers a specific capacity of 178.59 C/g at the current density of 1.0 A/g along with an outstanding energy density of 40.92 Wh/kg. Besides, the device was able to deliver a high-power density of 4125 W/kg in parallel to an energy density of 33.26 Wh/kg at the cost of 5.0 A/g current density. To investigate the cyclic life of the device, it had been tested for consecutive 3000 charge-discharge cycles to study its coulombic efficiency and specific capacity retention. The device's performance was remarkable as it retains specific capacity of about 89.21%, and the coulombic efficiency retained up to 91.10% after the stability testing. Thus, our analysis depicts that the hydrothermally synthesized silver cobalt phosphate can be utilized as a high-energy density anode material for supercapattery devices.