MnO2/carbon nanotube free-standing electrode recycled from spent manganese-oxygen battery as high-performance supercapacitor material

• Published in: Journal of materials science Vol. 57; no. 19; pp. 8818 - 8827
• Main Authors: Li, Zihan, Xiao, Dewei, Xu, Chengyang, Li, Zhiwei, Bi, Sheng, Xu, Hai, Dou, Hui, Zhang, Xiaogang
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2022; Springer Nature B.V
• Subjects: Activated carbon; Asymmetry; Capacitance; Carbon; Carbon nanotubes; Cathodes; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystal structure; Crystallinity; Crystallography and Scattering Methods; Electrode materials; Electrodes; Energy Materials; Energy storage; Flux density; Lithium; Manganese dioxide; Materials Science; Metal air batteries; Oxygen; Polymer Sciences; Rechargeable batteries; Roasting; Solid Mechanics; Storage batteries; Supercapacitors
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-022-07223-7

Metal–oxygen batteries have been growing rapidly as an energy storage technology in light of their high specific energy density. However, waste metal–oxygen batteries will raise many environmental issues; therefore, the recycling and reusing of the spent metal–oxygen batteries has attracted great attention. Herein, we report the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) as a redox mediator for manganese–oxygen battery (MOB). Trace amounts of PTIO result in the discharge capacity of MOB increase to 2588 mAh g −1 and enhance the formation of manganese dioxide (MnO 2 ) with toroidal appearance and high crystallinity on the cathode. After being used, the dismantled MnO 2 /carbon nanotube (CNT) cathode can be reused as an electrode for supercapacitor via simple calcining at mild temperature. The recycled free-standing MnO 2 /CNT electrode demonstrates an exceptional specific capacitance (253.86 F g −1 ) at a current density of 0.5 A g −1 in a 0.5 M Na 2 SO 4 electrolyte. Moreover, we prepare an asymmetric supercapacitor fabricated with the recycled MnO 2 /CNT electrode and activated carbon (AC), which exhibits excellent energy density (32.00 Wh kg −1 at 413.70 W kg −1 ) with 78.26% retention over 6000 cycles. This work provides a promising strategy to derive high-quality and high-value MnO 2 /CNT electrode materials from the spent MOBs. Graphical abstract It’s the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) as a redox mediator for manganese-oxygen battery (MOB). The recycled manganese dioxide (MnO 2 )/carbon nanotube (CNT) cathode can be reused as an electrode for supercapacitor via simple calcining at mild temperature. The recycled MnO 2 /CNT electrode shows the toroidal appearance and high crystallinity. Furthermore, the asymmetric supercapacitor fabricated with the MnO 2 /CNT free-standing electrode displays high specific capacitance, superior energy density, and good cyclic ability.