High-capacity vanadium nitride anode materials synthesized by melamine-assisted pyrolysis

Abstract

Vanadium nitride is a typical pseudocapacitive material that has attracted much attention among electrode materials as a result of its high theoretical capacity and wide voltage window. Nevertheless, its poor rate capability, cycling stability, and dissolution in alkaline electrolytes have restricted its practical applications. In this work, these problems are addressed by utilizing melamine-assisted pyrolysis and a dual-carbon composite strategy. A structurally controllable clustered shuttle vanadium-MOF is selected as the precursor. By subjecting it to high-temperature pyrolysis, melamine-derived carbon is coated on the surface of the vanadium-MOF, resulting in the formation of vanadium nitride-doped carbon electrode materials. Interestingly, they have a capacity of 407.5 F g⁻¹ at a current density of 0.5 A g⁻¹, with a capacity retention of 82.02% and a Coulombic efficiency of 80.59% after 10 000 cycles at a current density of 3 A g⁻¹. When assembled into a device, the device shows a power density of 775 W kg⁻¹ and an energy density of 39.29 W h kg⁻¹. It is worth noting that the energy density reaches 15.82 W h kg⁻¹ when the maximum power density of 3, 875 W kg⁻¹ is attained. These anode materials have broad applications in energy storage systems, providing an innovative approach to developing new materials.