Explanation of anomalous rate capability enhancement by manganese oxide incorporation in carbon nanofiber electrodes for electrochemical capacitors
Journal article, 2020

Electrochemical capacitors (ECs) can provide ultra-long cycle life and ultra-fast energy delivery, characteristics which most battery technologies lack. Making composites out of carbon and pseudocapacitive materials is a popular strategy directed on narrowing the gap in energy density with regard to batteries. Usually, the incorporation of pseudocapacitive materials leads to a decrease in power performance compared to a pure carbon matrix, due to inferior electrical conductivity. This work, however, presents significant improvement in rate capability demonstrated by a composite electrode containing carbon nanofibers (NCNF) and manganese oxides (MnO2). The NCNF/MnO2 is prepared with a common method through the reaction with permanganate. The material has excellent performance metrics, especially a 78.2% rate capability (capacitance retention at 15 A g−1 relative to 0.5 A g−1), more than 10 times that for the NCNF carbon matrix. The exceptional enhancement can be explained by the development of micropores and surface area of NCNF, thus alleviating the “pore starvation” issue, and surface functional groups variation that enhances capacitive performance. This work highlights the importance of paying attention to the modification of carbon substrate when investigating carbon composite electrodes e.g. carbon/MnO2 networks.

Supercapacitor

Porosity

Carbon nanofiber

MnO 2

Surface functional group

Rate capability

Author

Qi Li

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Wallenberg Wood Science Center (WWSC)

Volodymyr Kuzmenko

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Mohammad Mazharul Haque

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Mengqiao Di

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Per-Anders Carlsson Group

Anderson David Smith

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Per Lundgren

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Peter Enoksson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Wallenberg Wood Science Center (WWSC)

Electrochimica Acta

0013-4686 (ISSN)

Vol. 340 135921

Subject Categories

Inorganic Chemistry

Materials Chemistry

Composite Science and Engineering

DOI

10.1016/j.electacta.2020.135921

More information

Latest update

4/15/2020