Novel approach to utilise highly conductive but electrochemically unstable current collector materials in textile supercapacitor electrodes

Metal-based materials, such as silver or copper, are highly desired as current collector materials for flexible energy storage due to their excellent electrical properties but lack the long-term operational electrochemical stability. Herein we report a method to prevent the corrosion of such materials, while fully exploiting their electrical properties. This was achieved by covering the current collector with an electrochemically stable conductive carbon-based layer. The barrier layer allows the flow of charge between the electrically conductive elements of the textile composite electrodes, while protecting the current collector from contacting the electrolyte. The areal power and energy densities obtained after 1000 bending cycles were 29.88 and 0.01 mWh cm−2, respectively, with no evident degradation. Additionally, patterned current collectors were designed to deposit lower quantities of ink, without detriment to electrochemical performance. After 1000 bending cycles, the textile composite supercapacitors (TCSs) having 50% less current collector material demonstrated an areal power and energy density of 28.08 and 0.01 mWh cm−2, respectively. The proposed strategy is essential in enabling the utilisation of highly conductive metal-based inks, improving the rate capabilities and long-term operation of wearable energy storage devices, while maximising specific power and energy densities of TCSs, and decreasing the manufacturing cost.