Stretchable Superhydrophobic Supercapacitor with Excellent Self-Healing Ability

Flexible supercapacitors have attracted widespread attention due to the rapid development of wearable electronics. Nevertheless, most supercapacitors will degrade after being stretched and cannot work underwater. Here, a new kind of stretchable superhydrophobic supercapacitor was proposed. On the basis of the freeze-thaw treatment of PVA hydrogel, carrageenan and carbon nanotubes (CNTs) were further introduced to construct a triple network hydrogel that achieved self-healing, high elasticity, and stretchability simultaneously. Then, hydrophobic modified CNTs and NiO/CoO nanoparticles were sprayed onto the surface of the hydrogel to construct electrodes. The energy storage performance was improved by combining pseudocapacitive (CoO and NiO) and electric double-layer capacitive (MWCNT) behaviors. The superhydrophobic supercapacitor has excellent flexibility, self-healing, and self-cleaning properties. Furthermore, it can maintain superhydrophobic and good energy storage performance even after being stretched 400%, abraded 65 cycles, and cut 20 times. Owing to superhydrophobicity, this supercapacitor would have a bright application for underwater workings.