NiCo-OH Nanosheets Coated with NiCoS Nanosheets for Supercapacitors and Alkaline Zinc Batteries

Herein, a reverse bias heterojunction NiCoS/NiCo-OH with mesopores as the positive electrode was constructed by interface engineering. During the process of charging, the application of a positive bias potential by the external circuit to the reverse bias heterojunction NiCoS/NiCo-OH enhances the accumulation of charges within the NiCoS nanosheets. Under the modulation of the built-in electric field at the interface, the mesoporous interface of NiCo-OH acts as a receiver, collecting charges from NiCoS nanosheets and forming a channel leading to efficient ion diffusion and charge transfer. The specific capacity of the NiCoS/NiCo-OH electrode is up to 406.5 mA h g–1 at 1 A g–1. It demonstrates ultrahigh rate performance, reaching 81.9% (50 A g–1) and 77.4% (100 A g–1). The hybrid supercapacitor NiCoS/NiCo-OH//FNG shows a high energy density of 51.3 W h kg–1 at 1650 W kg–1. Moreover, the capacity of the Zn||NiCoS/NiCo-OH battery reaches 419.1 mA h g–1cathode at 1 A g–1, and it can still maintain 73% (306.3 mA h g–1cathode) at 100 A g–1.