Transformation of supercapacitive charge storage behaviour in a multi elemental spinel CuMn2O4 nanofibers with alkaline and neutral electrolytes

• Main Authors: Kunwar, Ria, Krishnan, Syam G., Izan Izwan, Misnon, Zabihi, Fatemeh, Yang, Shengyuan, Yang, Chun-Chen, Rajan, Jose
• Format: Article
• Language: English; English
• Published: Springer 2021
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://umpir.ump.edu.my/id/eprint/37936/1/Transformation%20of%20supercapacitive%20charge%20storage%20behaviour%20.pdf; http://umpir.ump.edu.my/id/eprint/37936/2/Transformation%20of%20supercapacitive%20charge%20storage%20behaviour_FULL.pdf; http://umpir.ump.edu.my/id/eprint/37936/; https://doi.org/10.1007/s42765-021-00083-x; https://doi.org/10.1007/s42765-021-00083-x

Electrode material has been cited as one of the most important determining factors in classifying an energy storage system’s charge storage mechanism, i.e., as battery-type or supercapacitive-type. In this paper, we show that along with the electrode material, the electrolyte also plays a role in determining the charge storage behaviour of the system. For the purpose of our research, we chose multi-elemental spinal type CuMn2O4 metal oxide nanofibers to prove the hypothesis. The material is synthesized as nanofibers of diameter ~ 120 to 150 nm in large scales by a pilot scale electrospinning set up. It was then tested in three different electrolytes (1 M KOH, 1 M Na2SO4 and 1 M Li2SO4), two of which are neutral and the third is alkaline (KOH). The cyclic voltammograms and the galvanostatic charge–discharge of the electrode material in a three-electrode system measurement showed that it exhibit different charge storage mechanism in different electrolyte solutions. For the neutral electrolytes, a capacitive behaviour was observed whereas a battery-type behaviour was seen for the alkaline electrolyte. This leads us to conclude that the charge storage mechanism, along with the active material, also depends on the electrolyte used.