TiO2 nanoparticles-functionalized two-dimensional WO3 for high-performance supercapacitors developed by facile two-step ALD process

Abstract

TiO2 nanoparticles-functionalized two-dimensional (2D) WO3 (TiO2NP-WO3) films fabricated by the facile two-step atomic layer deposition (ALD) process with following post-annealing at 380°C were investigated as electrode material for supercapacitors. The surface functionalization of 2D WO3 electrode by TiO2 nanoparticles significantly enhanced the specific capacitance by ∼1.5 times over the pure 2D WO3 electrode. Transition of electric double-layer capacitive behavior to the pseudo-capacitive behavior was also observed. Besides, the TiO2NP-WO3 electrode exhibited faster charge transfer than the pure 2D WO3 electrodes, due to the conduction modulation from the development of TiO2-WO3 heterojunctions. The decoration of TiO2 nanoparticles on 2D WO3 electrodes by this two-step ALD process with the following post-annealing has been solidly proven to a facile and effective method to enhance supercapacitor performances along with advantage of ALD technique for fabrication of large-scale, ultrathin films over other conventional methods. The fabrication strategy of the 2D TiO2NP-WO3 electrodes presented in this work may open a new pathway for the design and functionalization of the other 2D nanomaterials for the energy conversion and storage devices.