TY - JOUR
T1 - Insight into the origin of carbon corrosion in positive electrodes of supercapacitors
AU - Tang, Rui
AU - Taguchi, Kaishi
AU - Nishihara, Hirotomo
AU - Ishii, Takafumi
AU - Morallón, Emilia
AU - Cazorla-Amorós, Diego
AU - Asada, Toshihiro
AU - Kobayashi, Naoya
AU - Muramatsu, Yasuji
AU - Kyotani, Takashi
N1 - Funding Information:
The authors are thankful to Ms Q. Lin and Ms M. Ohwada for their experimental contributions. This work was supported by JSPS KAKENHI (grant no. 15H01999 and 17H01042); the Dynamic Alliance for Open Innovation Bridging Human, Environment, and Materials program; and the Network Joint Research Centre for Materials and Devices. R. T. acknowledges the China Scholarship Council for the nancial support. MINECO and FEDER (CTQ2015-66080-R MINECO/FEDER) are acknowledged for nancial support.
PY - 2019
Y1 - 2019
N2 - While activated carbons are used as electrode materials in commercial supercapacitors, they are not stable under high voltage operation especially at a positive-electrode side, and this limits the working voltage of supercapacitors to about 2.8 V in organic electrolytes. Thus, revealing the specific carbon chemical structures causing the corrosion is of great significance to come up with ideas of avoiding the corrosion reactions and eventually to achieve high energy density by expanding the working voltage. In this work, a variety of carbon materials are analyzed with many characterization techniques such as X-ray diffraction, Raman spectroscopy, N2 adsorption, magnetic susceptibility measurement, and temperature programmed desorption up to 1800 °C, to find out the origin of corrosion reactions in an organic electrolyte. While carbon crystallinity and porosity are not directly related to the positive-electrode corrosion, a good correlation is found between the corrosion charge and the number of carbon edge sites terminated by H and oxygen-functional groups which are decomposed and release CO. It is thus concluded that the H-terminated edge sites, phenol, ether and carbonyl groups are electroactive sites for the carbon materials used in the positive electrode of supercapacitors.
AB - While activated carbons are used as electrode materials in commercial supercapacitors, they are not stable under high voltage operation especially at a positive-electrode side, and this limits the working voltage of supercapacitors to about 2.8 V in organic electrolytes. Thus, revealing the specific carbon chemical structures causing the corrosion is of great significance to come up with ideas of avoiding the corrosion reactions and eventually to achieve high energy density by expanding the working voltage. In this work, a variety of carbon materials are analyzed with many characterization techniques such as X-ray diffraction, Raman spectroscopy, N2 adsorption, magnetic susceptibility measurement, and temperature programmed desorption up to 1800 °C, to find out the origin of corrosion reactions in an organic electrolyte. While carbon crystallinity and porosity are not directly related to the positive-electrode corrosion, a good correlation is found between the corrosion charge and the number of carbon edge sites terminated by H and oxygen-functional groups which are decomposed and release CO. It is thus concluded that the H-terminated edge sites, phenol, ether and carbonyl groups are electroactive sites for the carbon materials used in the positive electrode of supercapacitors.
UR - http://www.scopus.com/inward/record.url?scp=85063389309&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85063389309&partnerID=8YFLogxK
U2 - 10.1039/C8TA11005K
DO - 10.1039/C8TA11005K
M3 - Article
AN - SCOPUS:85063389309
VL - 7
SP - 7480
EP - 7488
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
SN - 2050-7488
IS - 13
ER -