2, Beijing Jiaotong University, Beijing, Beijing, , China
The fast-growing market for portable electronic devices and the demand for hybrid electric vehicles leads to the availability of high-performance energy storage systems. Supercapacitors have received considerable attention because of their high power density, fast recharge capability and long cycle life. Pseudocapacitors provide promising capacitive performance in energy storage and power delivery. Among the various types of pseudocapacitors, thin layers of mesoporous carbon encapsulated CoOx is desirable since it combines the high electronic conductivity of the carbon and the large capacity of CoOx. We developed a unique synthesis strategy to guarantee that the CoOx nanoparticles are completely confined within the mesoporous carbon tubes. The size of the CoOx nanoparticles ranges from 5 to 50 nm. The electrochemical properties of the synthesized mesoporous carbon encapsulated CoOx composite system was evaluated with a 3-electrode configuration and 6M KOH. The measured specific capacitance was 3750 F/g at a current density of 1A/g. Even when the current density was increased to 200A/g a specific capacity of 1550 F/g was still achieved. The high capacitive performance at high current densities originates from the mesoporous nature of the carbon tubes and the finely dispersed CoOx nanoparticles.
 Y. Zheng, Z. Li, J. Xu et al. Nano Energy, 20(2016) 94-107.
 This research was funded by the College of Liberal Arts and Sciences of Arizona State University. H. Wu acknowledges the financial support from the China Scholarship Council. The authors gratefully acknowledge the use of facilities within the LeRoy Eyring Center for Solid State Science at Arizona State University.