Calligraphic ink enabling washable conductive textile electrodes for supercapacitors

The appeal of wearable devices for future electronics has stimulated scientists to unearth novel materials to meet the technological demands of modern society. However, the washability issue still remains a significant challenge. We showed that calligraphic ink, used as a writing tool in East Asian areas for thousands of years, could present a route to translate washable and wearable electrodes into a reality. We prepared washable electrodes by simply coating textiles with the ink. It was observed that the electrical and mechanical performance of the fabricated electrodes remained nearly unchanged even after 10 vigorous laundering cycles using a regular washing machine. In addition, supercapacitors made with those electrodes exhibited excellent cycling stability and high energy/power density. These results establish that everyday calligraphic ink is a simple yet powerful resource for fashioning normal textiles into washable and wearable electrodes for supercapacitors.