Pores enriched CoNiO2 nanosheets on graphene hollow fibers for high performance supercapacitor-battery hybrid energy storage

Abstract

A pore enriched CoNiO2@reduced graphene oxide hollow fiber (CoNiO2@rGOF) is constructed as battery-type materials via the combination of wet-spinning and hydrothermal approaches. Thanks to the in-situ nucleation and growth of the porous and ultrathin CoNiO2 nanosheets, as well as the good conductive and hollow structure of rGOF, the as-obtained CoNiO2@rGOF cathode delivers specific capacities of 645.8 and 460.0 C g−1 at 2 and 50 A g−1, respectively, displaying an extraordinary rate capability. Significantly, it can be cycled more than 50,000 times with an amazing capacity increase of 42.9%. The CoNiO2@rGOF//rGOF supercapacitor (SC)-battery hybrid device achieves an energy density of 43.99 Wh kg−1 at a power density of 1.70 kW kg−1; even at a high power density of 21.61 kW kg−1, the energy density could stay as high as 38.41 Wh kg−1. Importantly, a 2.0 V light emitting diode (LED) could be lit up for more than half an hour by two hybrid devices in series. This work describes here provides a versatile pathway to construct graphene hollow fibers-based hybrid materials for various applications.