A Flexible Superhydrophobic Supercapacitor with Enhanced Metal Ion Coordination by Electrochemical Optimization

Abstract

Portable energy storage is developing rapidly with the miniaturization and integration of devices, and flexible supercapacitors are one of the important development directions. Nevertheless, the performance of most supercapacitors will be dramatically degraded after being eroded by water droplets or repeatedly stretched. In this research, the superhydrophobic electrode is constructed by a chemical modification. After the water droplets impale the electrode surface, they will eject, which prompts the surface dust to roll down and demonstrate a self-cleaning property. Meanwhile, an electrochemistry functionalization strategy was applied onto the hydrogel, which not only enhanced the mechanical properties but also effectively improved the energy storage density. The integrated superhydrophobic supercapacitor has a specific capacitance of 97.2 F/g at a current density of 0.8 mA/cm 2 , and a capacitor retention rate of 95.5% after 3500 cycles. Furthermore, it can withstand bending 2000 times and 24 h of immersion with either strong acid or alkali and can achieve long-term underwater work (3500 h). This versatile supercapacitor has potential applications in integrated flexible electronic systems by powering functional devices in harsh environments.