Mechanically robust and conductive zwitter ionic polymer coated electrospun nanofibrous electrolyte membranes for wireless human motion detection and capacitor applications

To address the limitations of poor ionic conductivity, low toughness, and high mass ratios in hydrogel-based electrolytes for flexible energy storage and wearable devices, here in a simple synthesis method of poly(ionic liquids) (PILs) based electrolyte membrane was developed. Briefly, PILs were utilized to coat electrospun PVDF-HFP nanofibrous membranes, resulting in ionically conducting composite electrolyte membranes (CPEMs) with enhanced physio-chemical properties. The obtained CPEMs exhibited an ionic conductivity of 0.056 S/m, along with a high tensile strength of 5.06 MPa and elongation to break of 156%. Furthermore, we utilized these CPEMs as the electrolyte in symmetric capacitors by sandwiching them between carbon nanotube (CNT) coated Ni-foams. The resulting capacitors demonstrated a specific capacitance of 170 F/g, an energy density of 53.41 Wh/kg, and a power density of 108.9 W/kg at an applied current of 1 mA. The suitability of these CPEMs as chemo-resistive sensors was investigated by attaching them to different body parts and monitoring changes in resistance during physical motion. The results demonstrated that the CPEMs exhibited effective gauge factors ranging from 1.85 to 6.44 and could detect movements up to 1% strains.