Atomic layer deposition of TiN layer on TiO2 nanotubes for enhanced supercapacitor performance

In this paper, vertical ordered TiO
2
nanotubes (TNT) with highly conductive titanium nitride (TiN) are sequentially fabricated by electrochemical anodization on Ti foils and atomic layer deposition (ALD) technique. The hollow structure of TNT and highly conductive TiN allow the electrolyte to permeate into TNT and prompt faster charge transfer. Thus, the TNT-TiN composite electrode yields the maximum specific capacitance of 10.01 mF/cm
²
at a scanning rate of 1mV/s, which is 24.4 times higher than that of pristine TNT. Importantly, TNT-TiN also present outstanding cycling stability with 91.9% retention of original specific capacitance after 2000 cycles. These excellent performances showed TNT-TiN electrodes could be regarded as promising material for electrical double-layer capacitor (EDLC) or as a good scaffold material for pseudocapacitors, which should be pave a new avenue for energy storage devices.