AUTHOR=Sun Leimeng , Wang Xinghui , Wang Yurong , Xiao Dongyang , Cai Weifan , Jing Yuan , Wang Yanrong , Hu Fangjing , Zhang Qing TITLE=In-situ Functionalization of Metal Electrodes for Advanced Asymmetric Supercapacitors JOURNAL=Frontiers in Chemistry VOLUME=7 YEAR=2019 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00512 DOI=10.3389/fchem.2019.00512 ISSN=2296-2646 ABSTRACT=

Nanostructured metal-based compound electrodes with excellent electrochemical activity and electrical conductivity are promising for high-performance energy storage applications. In this paper, we report an asymmetric supercapacitor based on Ti and Cu coated vertical-aligned carbon nanotube electrodes on carbon cloth. The active material is achieved by in-situ functionalization using a high-temperature annealing process. Scanning and transmission electron microscopy and Raman spectroscopy confirm the detailed nanostructures and composition of the electrodes. The TiC@VCC and CuxS@VCC electrodes show a high specific capacity of 200.89 F g−1 and 228.37 F g−1, respectively, and good capacitive characteristics at different scan speeds. The excellent performance can be attributed to a large surface area to volume ratio and high electrical conductivity of the electrodes. Furthermore, an asymmetric supercapacitor is assembled with TiC@VCC as anode and CuxS@VCC as cathode. The full device can operate within the 0–1.4 V range, and shows a maximum energy density of 9.12 Wh kg−1 at a power density of 46.88 W kg−1. These findings suggest that the metal-based asymmetric electrodes have a great potential for supercapacitor applications.