Self-Charging Zinc-Ion Battery Using a Piezoelectric Separator Immersed in a Hydrogel Electrolyte

Emerging portable energy systems with integrated sustainability and improved safety have garnered growing interest in wearable electronics. Herein, a self-charging zinc-ion battery is successfully developed by integrating a PVDF-ZnO piezoelectric separator immersed in a quasi-solid-state hydrogel electrolyte (prepared using a 3 m Zn(CF₃SO₃)₂) solution that is sandwiched between a FeVO₄ cathode and a zinc anode. This battery effectively captures energy through controlled tapping, eliminating the need for external charging and enabling sustainable energy storage. This self-charging battery can be charged up to 181.23 mV under continuous tapping for 300 s. Upon the cease of tapping, there is a slight decline in the induced potential, which then stabilizes and maintains a consistent potential. Five self-charging batteries connected in series and tapped simultaneously for 300 s generate a potential of 290 mV, whereas five batteries connected in series and tapped one by one induce a potential of 345 mV. This is the first time that a piezoelectric self-charging zinc-ion battery is reported. This study unveils a transformative strategy for realizing next-generation wearable electronics with a self-charging zinc-ion battery design that prioritizes both sustainability and safety.