NiCoP@amorphous carbon composites with 3D core-shell structure for high-performance asymmetric supercapacitors

Abstract

In this paper, a facile bio-templating method is proposed to prepare NiCoP coated on amorphous carbon (NiCoP@AC) composite electrode materials with using bagasse as template and carbon source. NiCoP nanowire network arrays precursors coating on bagasse substrate with high yield were prepared via a novel synthesis strategy utilizing the toluene-water interface reaction process, which subsequently formed as NiCoP@AC composite electrode materials after phosphating process. The assembled core-shell structure attenuated the volume expansion during charging and discharging, additionally, the overall electrical conductivity of the composite was also improved owing to the characteristic of bagasse biochar. The NiCoP@AC electrode exhibited high specific capacitance (1706 F g−1 at 1 A g−1), outstanding rate capability (82.1 % capacity retention from 1 to 20 A g−1) and good cycling stability (retaining 80.0 % capacitance over 5000 cycles). In addition, bagasse biomass activated carbon (BAC) was prepared via a typical alkaline activation process for the use as negative electrode. The as-fabricated NiCoP@AC//BAC supercapacitor displayed a high energy density of 46.2 Wh kg−1 at a power density of 807.3 W kg−1, and an excellent capacitance retention rate (88.5 % after 5000 cycles), suggesting that the as-prepared NiCoP@AC electrode materials have wide application prospects in high-performance supercapacitors.