Hierarchical Mn₂O₃ Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

Feilong Gong; Shuang Lu; Lifang Peng; Jing Zhou; Jinming Kong; Dianzeng Jia; Feng Li

doi:10.3390/nano7120409

Hierarchical Mn₂O₃ Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

Nanomaterials (Basel). 2017 Nov 23;7(12):409. doi: 10.3390/nano7120409.

Authors

Feilong Gong^{1

2}, Shuang Lu³, Lifang Peng⁴, Jing Zhou⁵, Jinming Kong⁶, Dianzeng Jia⁷, Feng Li^{8

9

10}

Affiliations

¹ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. feilonggong@zzuli.edu.cn.
² State Laboratory of Surface and Interface Science and Technology, Zhengzhou University of Light Industry, Zhengzhou 450002, China. feilonggong@zzuli.edu.cn.
³ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. ls102511@163.com.
⁴ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. 18736048695@163.com.
⁵ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. jzhou_chem@zzuli.edu.cn.
⁶ School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. j.kong@njust.edu.cn.
⁷ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. jdz@xju.edu.cn.
⁸ Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, China. fengli@zzuli.edu.cn.
⁹ State Laboratory of Surface and Interface Science and Technology, Zhengzhou University of Light Industry, Zhengzhou 450002, China. fengli@zzuli.edu.cn.
¹⁰ American Advanced Nanotechnology, Houston, TX 77459, USA. fengli@zzuli.edu.cn.

Abstract

Porous Mn₂O₃ microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn₂O₃ microspheres by first producing MnCO₃ microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO₃ microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn₂O₃ nanorods consisting of microspheres. The C@Mn₂O₃ microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn₂O₃ microspheres prepared at 500 °C show high specific capacitances of 383.87 F g^-1 at current density of 0.5 A g^-1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn₂O₃ microspheres after annealed at 500 °C and activated carbon (AC) show an energy density of up to 77.8 Wh kg^-1 at power density of 500.00 W kg^-1, and a maximum power density of 20.14 kW kg^-1 at energy density of 46.8 Wh kg^-1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D) hierarchical structure in-situ coated with carbon.

Keywords: Mn2O3 microspheres; amorphous carbon; hierarchical materials; in-situ carbonization; pseudocapacitors.