Electrochemical kinetic study and performance evaluation of surface-modified mesoporous sodium carbonophosphates nanostructures for pseudocapacitor applications

Sodium carbonophosphates as a novel low-cost and safe electrode material have been widely researched for sodium and lithium-ion battery application. Here, we report the pseudocapacitive behavior of the surface-modified mesoporous Na3MCO3PO4 (M=Ni, Co, Mn and Cu) nanostructure compounds in 1 M KOH electrolyte at room temperature. The electrochemical kinetic performances are studied using cyclic voltammetry (CV) cycled from 10 mVs−1 to 100 mVs−1. The electrodes are found to follow different kinetic behaviors depending on the scan rate. Overall, the deep reconstructed Na3CoCO3PO4 (Co(OH)2/Co3O4 agglomerated nanoplates) electrode provided a high specific capacitance compared to the deep reconstructed Na3MnCO3PO4 (Mn(OH)2/Mn3O4) and surface-modified Na3NiCO3PO4 (Ni(OH)2/Na3NiCO3PO4) and Na3CuCO3PO4 (Cu(OH)2/Na3CuCO3PO4) based electrodes at the current density of 20 Ag−1. The fabricated symmetric supercapacitor based on the Co(OH)2/Co3O4 delivered an energy density of 14.5 Wh kg−1 at the ultrahigh power density of 20 kW kg−1 demonstrating its excellent rate performance suitable for electric vehicle applications. The surface-modified Ni(OH)2/Na3NiCO3PO4 based SSC device showed high retention of 116% initial capacitance after 70,000 charging–discharging cycles, revealing excellent cycling stability. [Display omitted] •The pseudocapacitive behavior of the surface modified Na3MCO3PO4 (M=Ni, Co, Mn and Cu) nanostructures is tested.•The Na3MCO3PO4 (M=Co and Mn) undergo deep reconstruction in 1 M KOH to form M(OH)2/M3O4 nanocomposite.•The capacitive and diffusion currents contribution are clearly Identified.•The deep reconstructed Co(OH)2/Co3O4 symmetric supercapacitor delivers a high energy and power densities.