Solution-processable hierarchical-porous vanadium nitride films on silicon substrates for highly efficient symmetric supercapacitors

Abstract Vanadium nitride (VN) thin films with high specific capacitance are desirable in microsupercapacitors. Considering the integration with the silicon-based microelectronics, VN thin films on silicon wafers are needed. Here, hierarchical-porous VN thin films are deposited on silicon wafers through a solution-processable method. The prepared VN/silicon thin films show a high areal specific capacitance of ~60 mF cm−2 at 5 mV s−1 in 1 M KOH electrolyte. Symmetric devices deliver a high energy density of 21.2 and 12.8 mWh cm−3 at a power density of 2.0 and 16.8 W cm−3, respectively. Excellent retention 91.2% is achieved after 15,000 cycles. The results will provide a solution method for preparation of hierarchical-porous VN thin films on silicon wafers with excellent performance.