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.

Morphology Engineering of Hybrid Supercapacitor Electrodes from Hierarchical Stem-like Carbon Networks with Flower-like MoS2 Structures

“…As the scan rate increases, the specific capacitance drops as shown in Figure b. This is a typical behavior of electrochemical capacitors based on EDLC- and FPC-driven storage. , We note that the rate capability of our device (e.g., ∼63% at 5 mV/s) is similar to other studies adopting similar types of electrode materials, where the capacitance is limited by ion mobility and diffusivity under high scan rates. − …”

A V–Ni-based nitride heterostructure as a highly efficient electrode for flexible all-solid-state supercapacitors

“…1d). 33,34 Importantly, close contacts are observed between Ni (111), Ni 3 N (111) and VN (111), further confirming the formation of the VN/Ni 3 N–Ni heterojunction.…”

Sputter-Deposited Binder-Free Nanopyramidal Cr/γ-Mo2N TFEs for High-Performance Supercapacitors

“…The shape of the CV curves for all the Cr-doped Mo 2 N TFEs is almost similar, and the higher doping concentration of Cr/Mo 2 N-4 electrode exhibits the bigger CV area compared to pristine Mo 2 N indicating the excellent capacity behavior, outstanding reversibility and rate capability [ 34 ]. It is also noted that the CV curves of the metal nitride-based electrodes revealed a quasi-rectangular shape having a superior active surface area even at lower scan rates, suggesting excellent charge storage behavior and high-rate capability [ 44 – 47 ]. The areal capacity of the Mo 2 N and Cr-doped Mo 2 N-based TFEs can be calculated from the CV curves: where Q a is the areal capacity (mC/cm 2 ), I is the current (A), A is the exposed active area of the electrode (cm 2 ), and ν is the scan rate (mV s −1 ).…”