Electrodeposition of hydrated vanadium pentoxide on nanoporous carbon cloth for hybrid energy storage

Abstract

Electrodeposition is a simple and effective method for the synthesis of disordered hydrated vanadium pentoxide (V₂O₅·nH₂O). For the synthesis of energy storage electrodes with high power performance, electrodeposition of hydrated V₂O₅ inside carbon micropores is particularly attractive to synergize electric-double layer formation and lithium ion intercalation. Here, we demonstrate that hydrated V₂O₅ can be effectively electrodeposited in carbon micropores of activated carbon cloth. Our study indicates that carbon pores larger than 1 nm are essential for the effective decoration with hydrated V₂O₅. A thermal treatment after the electrodeposition is often used to enhance the crystal structure of hydrated V₂O₅. However, thermal annealing of the hydrated vanadium pentoxide decorated activated carbon cloth under an oxygen-rich environment at high temperature (>330 °C) leads to a significant loss of pore volume, leading to a decreased electrochemical performance. At low annealing temperature (200 °C), the vanadium pentoxide electrodeposited activated carbon cloth electrode exhibits a maximum specific capacity of 137 mA h g⁻¹ with stable cycle performance over 1600 cycles at a rate of 4C.