(Digital Presentation) Large-Scale Synthesis of Nanoporous Tungsten Oxide for Supercapacitor Application

Abstract

The development of materials delivering high specific capacitance and energy density is a major challenge for supercapacitors. Due to high redox activity, several metal oxides like RuO2, MnO2, MoO3, Fe3O4, WO3 and CoOx have been broadly utilized as the active material for pseudo-capacitors. Among these, tungsten oxide (WO3), being less toxic, chemically stable, and abundantly available, has become a potential candidate and is widely investigated for pseudo-capacitors. However, some modifications are required to bring its performance to a commercial scale. Various approaches like composites with carbon and other oxides, doping, confinement, and porosity improvement are followed to improve their performances. But there is a need to find the potential of solely WO3 for supercapacitors. Looking forward to it, we have synthesized highly porous pure WO3 using the solution-based nanoprecipitation method. Our approach offers the possibility of large-scale production of porous materials with tunable pore sizes and structures compared to the traditionally used solvent evaporation-induced self-assembly (EISA) method. Herein, we used PS-b-PAA block copolymer as pore creating agent, which was removed after giving thermal treatment. The prepared material was analyzed using Brunauer-Emmett-Teller (BET) and exhibited a high specific surface area of 55.5 m2 g-1 with an average pore diameter of 3.7 nm. A detailed crystallographic and morphological analysis of these materials was carried out to check the feasibility of our material for energy storage applications. Furthermore, electrochemical investigations were carried out in 3E and 2E device configurations. The electrochemical studies demonstrate that porous WO3 has achieved a specific capacitance of 555 F g-1 at 10 mV s-1 scan rate. Figure 1