title: MnO2 nanolayers on highly conductive TiO(0.54)N(0.46) nanotubes for supercapacitor electrodes with high power density and cyclic stability.
abstract: Pseudo-capacitive MnO2 supercapacitors are attracting intense interest because of the theoretically high specific capacitance (1370 F g(-1)) and low cost of MnO2. For the practical application, the power density and the cyclic stability of MnO2-based supercapacitors are expected to be improved. Increasing the efficiency of the current collection is an effective method to improve the power density for a given supercapacitor. Here, the highly conductive and electrochemically stable material, titanium oxynitride (TiO0.54N0.46), is used as the current collector. Uniform amorphous MnO2 nanolayers were deposited on metal-phase TiO0.54N0.46 nanotube arrays using a modified electrochemical deposition method. The resulting MnO2 supercapacitors exhibited a high power density of 620 kW kg(-1) at an energy density of 9.8 W h kg(-1). This is comparable to high-performance carbon-based electrochemical double layer capacitors in aqueous electrolytes. The high electron transport was enhanced with a highly conductive TiO0.54N0.46 scaffold. Ion transport was promoted in the nanotube structures that had porous walls. In addition, the close interfacial connection between MnO2 and TiO0.54N0.46 contributed to the excellent cyclic stability (ca. 92.0% capacitance retention after 100 000 cycles). These results indicated that the highly conductive and electrochemically stable titanium oxynitride is an excellent candidate for use as an electrode material in high performance supercapacitors.
authors.affiliation: National Laboratory of Solid State Microstructures, Ecomaterials and Renewable Energy Research Center (ERERC), Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China. zsli@nju.edu.cn zgzou@nju.edu.cn.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhaosheng
authors.initials: Z
authors.lastname: Li
authors.forename: Jianyong
authors.initials: J
authors.lastname: Feng
authors.forename: Shicheng
authors.initials: S
authors.lastname: Yan
authors.forename: Wenjun
authors.initials: W
authors.lastname: Luo
authors.forename: Jianguo
authors.initials: J
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zou