Effect of NASICON-type LiSnZr(PO4)3 ceramic filler on the ionic conductivity and electrochemical behavior of PVDF based composite electrolyte

Replacement of liquid electrolytes with polymer-based solid electrolytes is considered as the key to the realization of high-energy lithium metal anode in rechargeable batteries. However, the polymer electrolytes suffer from poor lithium-ion conductivity and low lithium-ion transference number. Poly(-vinylidene difluoride) (PVDF) based polymer-ceramic composite electrolytes were fabricated at room temperature via the solution casting method. The effect of NASICON-type lithium tin zirconium phosphate (LiSnZr(PO4)(3)) particles added as the ceramic filler to the PVDF + LiTFSI polymer-salt matrix on the structure, ionic conductivity, transference number, and electrochemical behaviour was studied. The x-ray diffraction (XRD) and fourier transform infrared (FTIR) absorption studies confirmed the structure of the fabricated polymer as the mixed (alpha+beta) phases of PVDF. The addition of LiSnZr(PO4)(3) ceramic filler resulted in the enhancement in Li+ conductivity of the polymer composite and the sample with 15 wt% ceramic filler (CPE-15) showed the highest lithium-ion conductivity of 5.76 x 10(-5) Scm(-1) at 300 K. The addition of 15 wt% LSZP improved the stability window up to 4.73 V as confirmed by linear sweep voltammetry (LSV). A significant improvement in (t(Li+)) resulted from the addition of ceramic filler. The reversibility of Li+ transport across the composite ceramic-polymer electrolyte (15 wt% CPE) was confirmed by galvanostatic charging-discharging of symmetric lithium (Li parallel to CPE parallel to Li) cell at various current density for 100 h. Li parallel to CPE parallel to LTO cells with Li4Ti5O15 (LTO) as the working electrode, CPE-15 as the Li+ conducting separator, and Li foil as the counter electrode were fabricated to demonstrate the application of the CPE-15 as the electrolyte in all-solid-state batteries. Li parallel to CPE parallel to LTO cell delivered a specific discharge capacity of 133 mAhg(-1) and 88% capacity retention after 20 cycles at 0.1C rate. (C) 2020 Elsevier B.V. All rights reserved.