The Design, Fabrications And Applications Of The Composite Nanostructure Electrodes Based On The ITO Nanowire Arrays

Efficient electron transfer was an important factor for obtaining high-performance electrochemical systems. The most common electrode for electron transfer and collection was ITO electrode. Surface contact area of the electrode with the electrolyte in the electrochemical systems decides the reaction sites of the electrodes and the electrolyte, which plays a crucial rule in the performance of the systems. However, the commercial ITO electrode possesses low surface area, which can only load very few active materials and restricts the performance of the electrochemical systems. ITO nanowire arrays, a kind of conductive metal doped metal oxide are considered as promising electrodes in the electrochemical systems for their good conductivity and high surface area. Herein, we introduced the conductive ITO nanowire arrays in various electrochemical systems such as photoelectrochemical water splitting and supercapacitors. We tried to improve their performances in the aspects of improving the loading massage of the active materials and the electrons transfer efficiency. The work was included as follows:1> We prepared ITO nanowire arrays using chemical vapor deposition method, and comapactly deposited α-Fe2O3 nanoparticles on the ITO nanowire arrays, which formed a core-shell structure (ITO@α-Fe2O3). The prepared optimized ITO@α-Fe2O3 electrode possessed higher absorption than planar α-Fe2O3 electrode, which was attibuted to the high surface area of the ITO@α-Fe2O3 electrode. The ITO@α-Fe2O3 electrode exhibited a high current density of 1.1 mA/cm2 at 1.23 V vs. RHE under AM 1.5 illumination. The value was twice higher than the planarα-Fe203 electrode.2> EIS curves was meatured to characterized the resistance in the ITO@α-Fe203 electrode and the interface between the ITO@α-Fe2O3 electrode and the electrolyte. Lower resistances in the ITO@α-Fe2O3 electrode and the interface were obtained for our prepared ITO@α-Fe2O3 electrode.3、ITO nanowire arrays were also introduced to the electrodes of supercapacitors. We electrodeposited Ni3S2 nanosheets on the chemical vapor deposited ITO nanowire arrays. The prepared electrodes exhibited a high specific capacitance of 1865 F/g, while the planar electrodes without ITO nanowire arrays displayed only about 800 F/g. We also obtained a high areal capacitance of 3.87 F/cm2. A good rate performance was also obtained when we introduced ITO nanowire arrays in the electrodes.4、The symmetric all-solid state flexible supercapacitors based on our prepared electrodes exhibited a high areal capacitance of 0.74 F/cm2, which was higher than many reported literatures. The flexible supercapacitor displayed an excellent energy density of 1.02 mWh/cm3 at 39.9 W/cm3, and can still maintain 0.56 mWh/cm3 at 399.9 mW/cm3. The capacitance can also maintain 90% when we bent the device at a radius of 1.5 cm, which demonstrate the potential application of our prepared electrodes in the flexible device.In this paper, ITO nanowire arrays were introduced to two electrochemical systems to improve the electron transfer and active materials loading in the systems. The strategy was considered as an effective way to improve the performance of electrochemical systems.