Abstract
Developing a novel electrode material with better electrochemical behavior and extended cyclability is a major issue in the field of hybrid capacitors. In this work, we propose a novel strategy for the facile synthesis of nickel-cobalt pyrophosphate nanoparticles anchored on graphitic carbon nitride (NiCoP(2)O(7)/g-C(3)N(4)) via the simple solvothermal method. Field emission scanning electron microscopy and transmission electron microscopy analysis revealed the uniform anchoring of NiCoP(2)O(7) nanocomposite on g-C(3)N(4) nanosheets. Benefitting from the effect of amorphous nature and a conductive matrix of the NiCoP(2)O(7)/g-C(3)N(4) (NP3) composite, the material achieves a specific capacitance of 342 F g(-1) at a scan rate of 5 mV s(-1). Impressively, the electrode shows long-term cycling stability with 100% capacitance retention over 5000 cycles. Employing activated carbon as an anode and as-prepared NP3 as a cathode, the assembled asymmetric hybrid cell exhibits high-energy density and exceptional cyclability (specific capacitance retention over 10 000 cycles). The outstanding electrochemical and cyclic stability is attributed to the shortest electron-ion pathway with effective interfacial interaction. The low electronic resistance of the NiCoP(2)O(7)/g-C(3)N(4) nanocomposite is revealed by varying the bias voltage variation in the electrochemical impedance spectroscopy. Our results promise better utilization of the bimetallic pyrophosphate-anchored g-C(3)N(4) matrix as a potential electrode for high-performance energy storage devices.