Enhancing rate capability of amorphous nickel phosphate supercapattery electrode via composition with crystalline silver phosphate

The performance of a supercapattery depends on its energy density, rate capability of charge and discharge and stability of electrode. Here in, a sonochemical method followed by calcination was applied to synthesize nickel phosphate-silver phosphate (Ni-3(PO4)(2)eAg(3)PO(4)) nanocomposites. Morphological studies revealed that crystalline Ag3PO4 (similar to 10 nm) was intimately anchored on the surface of amorphous Ni-3(PO4)(2), which benefits efficient charge transfer between the two metal phosphates. The optimized Ni-3(PO4)(2)eAg(3)PO(4) nanocomposite electrode exhibited a significant boost in rate capability from 29% (Ni-3(PO4)(2)) to 78% capacity retention with the maximum specific capacity of 478C/g at 1 A/g in 1M KOH electrolyte. The enhancement of rate capability originated from a more rapid electron-transfer rate and an augmentation of electroactive sites for electrolyte ion diffusion from the interfaces of porous Ni-3(PO4)(2) and an improvement in the electrical conductivity of crystalline Ag3PO4. The fabricated Ni-3(PO4)(2)e Ag3PO4//activated carbon-based supercapattery exhibited an energy density of 32.4 Wh/kg at 399.5 W/kg and excellent cyclic stability (similar to 82% capacity retention after 5000 cycles). (C) 2018 Elsevier Ltd. All rights reserved.