Development of heterostructure-like Zn2P2O7/NF@PPybinder-free electrode for high-energy hybrid supercapacitor applications

Abstract

In this work, we used the unique monoclinic Zn₂P₂O₇heterostructure as an efficient electrode material for high-performance pseudocapacitors, and 2 M KOH as the electrolyte. We developed an effective two-step hydrothermal and polymerisation process to produce an uncommon heterostructure of Zn₂P₂O₇@PPy on 3D Ni foam. Remarkably, the Zn₂P₂O₇ NSs electrode that was synthesised demonstrated a high specific capacitance (SC) of 1246 F/g at 1 A/g and a high current loading of 10 A/g at 612 F/g. Furthermore, its robust long-term cycling performance at high current density was demonstrated by its retention of approximately 94.6% during continuous 10,000 charge–discharge cycles at a current density of 5 A/g. An asymmetric supercapacitor (ASC) with a maximum energy density of 92.4 Wh/kg and a power density of 1800 Wk/g is constructed using Zn₂P₂O₇/NF@PPy (ZNPP) as the cathode material.The improved capacitive storage of the ASC device may be attributed to the linked Nanosheet structure and the optimal combination of Polypyrrole.