The influence of S-doped technique on supercapacitor performances for Co(OH)2@nitrogen-doped carbon dots

• Published in: Ionics 2023-08, Vol.29 (8), p.3249-3259
• Main Authors: Lin, Fanyi, Hong, Xiansheng, Chen, Zihan, Zheng, Yuying
• Format: Article
• Language: English
• Subjects: Aerogels; Capacitance; Carbon; Carbon dots; Charge materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Doping; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; Energy Storage; Graphene; Low conductivity; Nitrogen; Optical and Electronic Materials; Renewable and Green Energy; Specific energy; Sulfur; Supercapacitors
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-023-04982-4

Recently, Co-based materials have been widely used as a type of supercapacitor. However, Co-based materials are highly restricted due to their low conductivity, poor cyclic performance, and large structural changes during the charge/discharge process. Carbon materials have been found to improve the electrochemistry performance of Co(OH) 2 . In this work, sulfur doping was used to enhance the electrochemistry performance of Co(OH) 2 @nitrogen-doped carbon dots (Co(OH) 2 @NC) via hydrothermal approach. Here, as-prepared S-Co(OH) 2 @NC shows an excellent specific capacitance of 730 F g −1 at 1 A g −1 (much higher than that of pristine Co(OH) 2 @NC (592 F g −1 at 1 A g −1 )). An asymmetric supercapacitor (ASC) is assembled by S-Co(OH) 2 @NC (as a positive electrode) and graphene aerogels@NC (as a negative electrode), which presents a specific energy density as high as 39.59 Wh kg −1 with a power density of 639 W kg −1 . Moreover, the ACS manifests extraordinary cycle stability (75% capacitance retention after 8500 cycles). In summary, sulfur doping in electrode material has been proven as an efficient approach for improving the electrochemical performance in supercapacitor devices.