Lindberg, SimonNdiaye, Ndeye MatyManyala, Ncholu I.Johansson, PatrikMatic, Aleksandar2020-09-262020-09-262020-06Lindberg, S., Ndiaye, N.M., Manyala, N. et al. 2020, 'A VO2 based hybrid super-capacitor utilizing a highly concentrated aqueous electrolyte for increased potential window and capacity', Electrochimica Acta, vol. 345, art. 136225, pp. 1-6.0013-4686 (print)1873-3859 (online)10.1016/j.electacta.2020.136225http://hdl.handle.net/2263/76229In 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.en© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Highly concentrated electrolyteSupercapacitorStabilityNaTFSIVO2Article