Ryan, S.; Browne, M.P.; Zhussupbekova, A.; Spurling, D.; McKeown, L.; Douglas-Henry, D.; Prendeville, L.; Vaesen, S.; Schmitt, W.; Shvets, I.; Nicolosi, V.: Single walled carbon nanotube functionalisation in printed supercapacitor devices and shielding effect of Tin(II) Oxide. Electrochimica Acta 448 (2023), p. 142168/1-10
10.1016/j.electacta.2023.142168
Open Accesn Version
Abstract:
Due to this generation facing the biggest energy crisis of its lifetime, the spotlight has been shone more than ever on the rapid development of green energy and its storage. Supercapacitors are an integral technology in this renewable energy storage due to their high-power density. For an increased energy density however, one must expand the voltage window of the device and utilise electrolytes that allow for the maximum storage capability of the material. Single walled carbon nanotubes (SWCNT) were identified at the turn of the century as an excellent material for use in supercapacitor electrodes, however, at anodic potentials in sulphate-based electrolytes, they undergo irreversible oxidation which damage their electrical properties and affects long term cycling stability. Herein we provide an effective strategy to expand the voltage window of SWCNTs to 1.4 V in sulphate-based electrolytes through the small addition of tin (II) oxide (SnO), with a capacity of 102 F g-1 / 143 C g-1 at a current density of 2 A g-1. We study the effect of SnO and propose a pseudo-reversible oxidation reaction in which the SWCNTs are protected from oxidation through the formation of Sn3O4. Finally, an asymmetric device using MXene is assembled to illustrate the advantage of the expanded voltage window on energy density and cycling stability, with a capacity retention of 90% after 7,500 cycles at 10 A g-1.