Interfacial Engineering in Crystalline Cobalt Tungstate/Amorphous Cobalt Boride Heterogeneous Nanostructures for Enhanced Electrochemical Performances

Interfacial engineering is one of the feasible pathways to tune the characteristics and functions of nanomaterials. In this report, we successfully synthesized crystalline CoWO4/amorphous Co–B heterostructures that enable superior electrochemical performance. The electrodes overcome the defect of low conductivity of cobalt tungstate and also expose more active sites. The optimized CoWO4/Co–B electrode has a remarkable specific capacity of 177.4 C g–1 at 0.5 A g–1 and a great specific capacity retention of 100% at 5 A g–1 after 10,000 cycles with reasonable cycling stability. Moreover, the Co–B/CoWo4 electrode and activated carbon electrode are combined to assemble an asymmetric supercapacitor, which achieves 22.26 W h kg–1 maximum energy density at 200 W kg–1 and a capacity retention of 95.65% after 10,000 cycles at 2 A g–1. In general, the work shows the unique characteristics of the crystalline/amorphous nanoheterostructure and provides a direction for future studies on increasing the electrochemical character and application of nanomaterials through regulating the interface contact of composites.