Cumulenic sp‐Carbon atomic wires wrapped with polymer for supercapacitor application

Carbyne, the ideal linear atomic wire consisting of a single-atom thick chain of sp-carbon, is theoretically predicted to have around five times higher surface area than graphene, notable charge mobilities, as well as excellent optical and thermal properties. Despite these impressive properties, the exploitation of carbyne-like system as an electrochemical energy-storage electrode has not been reported so far. To address this challenge, we focused on experimentally available finite and short linear atomic chain of sp-carbon. Herein, we prepare solution-processed thin films of tetraphenyl [3]cumulenic sp-carbon atomic wires embedded in a polymer matrix, in which sp-carbon atomic wires feature three cumulated carbon-carbon double bonds terminated at each end by two phenyl groups. Raman and UV–visible spectroscopy confirms the presence of sp-carbons inside the polymeric matrix. Finally, we investigate the supercapacitor performance of cumulenic sp-carbon atomic wires embedded polymer in three aqueous electrolytes, namely 1 M Na2SO4 (neutral), 1 M H2SO4 (acidic), and 6 M KOH (basic). The results suggest 6 M KOH is the best electrolyte to obtain high charge-storage performance of device with areal capacitance of 2.4 mF/cm2 at 20 mV/s, 85 % cycle stability after 10000 charge-discharge cycles, and excellent frequency response.