All-Solid-State Electrospun Poly(vinylidene fluoride-co-hexafluoropropylene)/Li7.1La3Ba0.05Zr1.95O12 Nanohybrid Membrane Electrolyte for High-Energy Li-Ion Capacitors

Herein, we prepared all-solid-state electrospun poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP)/Li 7.1 La 3 Ba 0.05 Zr 1.95 O 12 nanohybrid membrane electrolytes (esHPMEs) by an electrospinning technique for high-energy Li-ion capacitors (LIC). As developed, an esHPME possesses superior thermal stability (150 °C) with improved separator characteristics like porosity and electrolyte uptake. Synergistic coupling between highly active garnet nanoparticles (Li 7.1 La 3 Ba 0.05 Zr 1.95 O 12 ) and a PVDF-HFP polymer has been confirmed by X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared analysis. The morphological feature of an esHPME was confirmed by field emission scanning electron microscopy analysis. Interactions between Li-ion conductive garnet nanoparticles and the host PVDF-HFP polymer (esHPME with 10 wt % Li 7.1 La 3 Ba 0.05 Zr 1.95 O 12 (LLBZO)) lead to an improved ionic conductivity of 3.30 × 10 –3 S cm –1 at 25 °C with a working potential of 4.6 V compared to a pure PVDF-HFP membrane. LIC (LiCoO 2 /esHPME (10 wt % LLBZO)/activated carbon) exhibits a superior specific capacitance of 123 F g –1 at a current density of 1 A g –1 with a capacity retention of 83% even after 1000 cycles. LIC assembled with 10 wt % LLBZO/PVDF-HFP nanohybrid membrane electrolyte exhibited a maximum energy and power density of 43.77 W h kg –1 and 7.973 kW kg –1, respectively. This work demonstrated the opportunities of all-solid-state Li-ion capacitor development using electrospun nanohybrid polymer membrane electrolytes that exploit the synergistic play between inorganic–organic entities.