Improved pseudocapacitor and water splitting in cobalt-anchored vanadium carbide MXene nanocomposite

Abstract

Electrochemical capacitors and hydrogen production through water splitting into constituent hydrogen (H2) and oxygen (O2) molecules are promising methods for long-lasting energy storage. This work presents a simple synthesis of a cobalt ion-doped vanadium carbide MXene (Co@V2CTx) nanocomposite, utilized as an effective, durable, and stable electrode for supercapacitors and as an electrocatalyst for water electrolysis. In 1 M KOH, the Co@V2CTx nanocomposite produced a capacitance of 1071 Fg-1 at 5 mVs−1 (more than 8 times that of pristine V2CTx MXene) and an energy and power density of 26.7 Whkg−1 and 325 Wkg-1 respectively at 1 Ag-1. In addition, the Co@V2CTx nanocomposite showed good hydrogen evolution reaction (HER) catalytic activity, exhibiting a minimal overpotential of 103 mV at 10 mAcm−2 and Tafel slope of 83 mVdec−1. The excellent performance of the Co@V2CTx nanocomposite is due to the synergistic effects produced when cobalt ions are intercalated into the vanadium carbide MXene, preventing restacking of sheets and boosting ion transfer. This work presents an easy and effective method for synthesizing MXene-based nanocomposites for energy storage and conversion applications.