Reduced graphene oxide decorated amorphous NiS2 nanosheets as high-performance anode materials for enhanced sodium-ion hybrid capacitors

摘要

Sodium-ion hybrid capacitors (SICs) combined two advantages of decent specific power of supercapacitors and specific energy of batteries have drawn much attention. Nevertheless, preparing suitable anodes for SICs is currently a main challenge due to that the large Na+ radius that will lead to a terrible volume expansion and sluggish reaction kinetics. To solve the above issues, we meticulously prepare reduced graphene oxide supporting amorphous NiS2 nanosheets (NiS2/rGO) composite by hydrothermal method. When used as anodes for sodium-ion battery, NiS2/rGO exhibits excellent specific capacity of 343.9 mA h g(-1) at 0.1 A g(-1) after 50 cycles. The structural evolution and pseudocapacitive contribution are analyzed through ex-situ XRD and CV analysis techniques. Simultaneously, the SICs assembled with biomass-derived porous carbon cathodes and NiS2/rGO anodes display superior specific energy and power with excellent cycling stability. Therefore, NiS2/rGO composite based on amorphous structure is a promising anode to promote the commercialization process of SICs.