Asymmetric Pseudocapacitors Based on Interfacial Engineering of Vanadium Nitride Hybrids

Abstract

Vanadium nitride (VN) shows promising electrochemical properties as an energy storage devices electrode, specifically in supercapacitors. However, the pseudocapacitive charge storage in aqueous electrolytes shows mediocre performance. Herein, we judiciously demonstrate an impressive pseudocapacitor performance by hybridizing VN nanowires with pseudocapacitive 2D-layered MoS2 nanosheets. Arising from the interfacial engineering and pseudocapacitive synergistic effect between the VN and MoS2, the areal capacitance of VN/MoS2 hybrid reaches 3187.30 mF cm−2, which is sevenfold higher than the pristine VN (447.28 mF cm−2) at a current density of 2.0 mA cm−2. In addition, an asymmetric pseudocapacitor assembled based on VN/MoS2 anode and TiN coated with MnO2 (TiN/MnO2) cathode achieves a remarkable volumetric capacitance of 4.52 F cm−3 and energy density of 2.24 mWh cm−3 at a current density of 6.0 mA cm−2. This work opens a new opportunity for the development of high-performance electrodes in unfavorable electrolytes towards designing high areal-capacitance electrode materials for supercapacitors and beyond.

Keywords

• VN nanowires
• MoS₂ nanosheets
• phase boundary
• pseudocapacitive charge storage
• asymmetric pseudocapacitor