Triboelectric Nanogenerator Driven Self-Charging and Self-Healing Flexible Asymmetric Supercapacitor Power Cell for Direct Power Generation.

The expeditious growth of portable electronics has endorsed the researchers to develop self-powered devices that synchronically harvest and store energy. However, it is quite challenging to integrate two distinct phenomena in a single portable device. Here, we emphasize the fabrication of a triboelectric driven self-charging and self-healing asymmetric supercapacitor (SCSHASC) power cell comprised of magnetic cobalt ferrite grown on a stainless steel fabric (CoFe2O4@SS) as positive and iron oxides decorated reduced graphene oxide grown on stainless steel fabric (Fe-RGO@SS) as negative electrodes separated by a KOH soaked self-healing polymer hydrogel electrolyte membrane. The membrane contains Fe3+ cross-linked polyacrylic acid while self-healing carboxylated polyurethane was utilized for encapsulation. Stainless steel fabric (SS) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/SS impregnated micro-patterned PDMS composite film-strip were employed as positive and negative triboelectric friction layers, accordingly. During mechanical deformation, the SCSHASC harvests electrical energy and subsequently stores it as electrochemical energy for sustainable power supply. The sandwich-type SCSHASC power cell (a supercapacitor unit sandwiched between two parallelly connected high-performance triboelectric nanogenerators) was charged up to 1.6 V within ~ 31 min under periodic compression/stress (F ≈ 17.6 N, f ≈ 3.80 Hz). Furthermore, the SCSHASC# (with two supercapacitor units in series) can instantly powers-up several portable electronic appliances on periodic compression. Thus, the SCSHASC with unique design will be extremely beneficial for self-powered electronics.