A VO2 based hybrid super-capacitor utilizing a highly concentrated aqueous electrolyte for increased potential window and capacity. (10th June 2020)

• Record Type: Journal Article
• Authors: Lindberg, Simon; Ndiaye, Ndeye Maty; Manyala, Ncholu; Johansson, Patrik; Matic, Aleksandar
• Is Part Of: Electrochimica acta. Volume 345(2020)
• Publication Date: 2020-06-10
• Subjects: Highly concentrated electrolyte -- NaTFSI -- VO2 -- Supercapacitor -- Stability; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.136225
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: In this work we demonstrate the application of a highly concentrated aqueous electrolyte to a hybrid supercapacitor cell. We combine an 8 m Sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) aqueous electrolyte with a nanostructured VO2 -cathode to enhance the voltage widow up to 2.4 V in a full cell. With the enhanced potential window, we are able to exploit the full contribution of the VO2 material, where a part is outside the stability window of standard alkaline aqueous electrolytes. We show that the VO2 material in the highly concentrated electrolyte provides a faradaic contribution even at the highest current density (25 A/g) and in this way increases the energy content also in high power conditions. The full cell shows a good efficiency but also a capacity fade over 500 cycles (39%) which is most likely related to dissolution of VO2 .