Fabrication and electrochemical properties of LATP/PVDF composite electrolytes for rechargeable lithium-ion battery

NASICON-type ceramic electrolyte has been considered as one of the potential candidates for solid state electrolytes with excellent conductivity at room temperature and good stability under atmosphere. In this paper, NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) was prepared by a solution method and dispersed in poly(vinylidene fluoride) (PVDF) to form LATP/PVDF composite electrolyte membranes (CEM) by the method of casting. The effects of LATP filler on the structure, morphology, ionic conductivity, stability of the LATP/PVDF CEM were studied. It was found that the LATP/PVDF CEM had high lithium ion conductivity and excellent electrochemical stability with the electrochemical stability window up to 5.67 V versus Li+/Li. The discharge capacity of lithium iron phosphate cells assembled with LATP/PVDF CEM was 163.5 mAh g−1 and retained over 95.7% of its initial capacity after 50 cycles. The results show that the addition of LATP filler to PVDF matrix increases the amorphous phase of the polymer by acting as a gel center and the concentration of Li+ is increased, which is beneficial to the synergism in the migration of Li+ and enhances the ionic conductivity.