Sputtered chromium nitride/carbon nanotubes hybrid structure for electrochemical capacitors

Abstract

Hybrid materials based on transition metal nitrides and carbon nanostructures are attracting intention for high-performance electrochemical energy storage systems. In this work, vertically aligned carbon nanotubes (CNTs) were grown over silicon substrate, followed by direct current plasma-sputtered deposition of chromium nitride (CrN) for different deposition times. The CNTs@ CrN electrodes exhibit vertically aligned cauliflower morphology with different degrees of dispersion on the substrate and were tested as electrodes for electrochemical capacitors (ECs). The areal capacitance of the CNTs@ CrN, as measured in 0.5 M H₂SO₄ electrolyte, was as high as 156.4 mF cm⁻² at a scan rate of 5 mV s⁻¹ with an excellent electrochemical retention of 90% over 10,000 cycles. Furthermore, the areal capacitance was found to increase with CrN thickness increase over the CNTs. This work demonstrates the beneficial use of CNT as template for transition metal nitride deposition and highlights CrN as a promising competitor to other transition metal nitrides already reported for ECs with similar structural morphology.