Fig. 3: Self-healing.
a Schematic of self-healing process. The hydrogel electrode self-heals under ambient conditions while the EL interlayer and Ni electrode self-heals at 50 °C. Water loss occurs in the hydrogel during heating, leading to a decrease in hydrogel conductivity; however, both water content and conductivity recover when the hydrogel regains water by absorbing moisture from air at RT (rehydration). b Photos showing a lit pristine fibre, the cut fibre, and the healed fibre which light up entirely again and is bent to a bending radius of ~5 mm. Scale bars, 1 cm. c SEM images showing self-healing of the cut interface on hydrogel electrode, EL interlayer, and Ni electrode, respectively. The black dashed boxes indicate the cut and healed area of the hydrogel electrode, which started to heal under ambient conditions during preparation for SEM and remained intact after heating. All fibres were heated at 50 °C for 24 h. Scale bar, 20 μm. d and e The decrease in water content (d) and ionic conductivity (e) of different hydrogels after heating at 50 °C for 24 h, followed by rehydration for 24 h. f The luminance at increasing fac for SHINE fibre before and after heating on the hotplate with 50 °C for 9 days followed by rehydration. g Representative tensile stress-strain curves of SHINE fibre before and after self-healing at different temperatures and the average self-healing efficiencies. Healing time for RT samples is 24 h while it is 48 h for 50 °C samples (heating for 24 h followed by rehydration for 24 h). The tensile rate is 20 mm·min−1. h Luminance of pristine SHINE fibre compared to luminance after the fibre was cut and healed. Vac = 400 V, fac = 300 Hz, TEL = 138 μm, and \(\vec{{\rm E}}\) = 2.9 V × μm−1. i Ratio between luminance at a point in time (L) and pristine luminance (L0) of healed SHINE fibre for over 10 months at different fac under ambient conditions. The Ni and ZnS loadings in samples for Fig. 3 were 60 wt% and 50 wt%, respectively. Error bars are standard deviations of results from three samples.
