Electrochemical activation and capacitance enhancement of expanded mesocarbon microbeads for high-voltage, symmetric supercapacitors. (1st November 2020)

• Record Type: Journal Article
• Authors: Yi, Tien-Yu; Dai, Cheng-Wei; Wang, Jeng-An; Ma, Chen-Chi M.; Hu, Chi-Chang
• Is Part Of: Electrochimica acta. Volume 359(2020)
• Publication Date: 2020-11-01
• Subjects: Expanded mesocarbon microbead -- Electrochemical activation -- High-voltage supercapacitor -- Symmetric cell; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.136941
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: To increase the specific energy of supercapacitors (SCs), the expanded mesocarbon microbead (EMCMB) is electrochemically activated in 1 M tetraethylammonium tetrafluoroborate in propylene carbonate (TEABF4 /PC) to construct a high-voltage but symmetric SC. The EMCMB is successfully made from MCMB through the oxidation in a solution containing concentrated H2 SO4, HNO3 and KMnO4 followed by a thermo-expansion treatment at 800°C. This carbon with a specific surface area of only 93.2 m 2 g −1 shows excellent capacitive performance after the electrochemical activation process in the highly positive or very negative potential regions in 1 M TEABF4 /PC, especially when an aqueous-based binder, KOH-partially-neutralized polyurethane-polyacrylic acid (denoted as PUPAH6 K4 ) was employed. These electrochemically activated EMCMB-PUPAH6 K4 electrodes are able to be charged and discharged reversibly in a wide potential range between −2.6 V and 1.4 V (vs. Ag/AgNO3 ). Consequently, a 4V SC consisting of two identical EMCMB-coated electrodes, i.e., symmetric, with good capacitive performances in 1 M TEABF4 /PC has been successfully demonstrated, showing the great application potential in the advanced high-voltage SCs.