Polymer Gel Electrolytes For Lithium-ion Battery Research

A gel-typed polymer electrolyte based on PVDF-HFP was studied.2801 and LBG was used as polymer matrix because of their different HFP ratio, DBP was used as plasticizer. The films were made by Bellcore method. Structure, crystallinity, liquid uptake and conductivity of the films with different ratio of PVDF\DBP\ SiO2 was determined. The mechanism of the Li+ ion in the composite electrolyte was briefly discussed. The highest conductivity of the polymer electrolyte is 0.938 x 10-3 S.cm-1, near to the applying level.Polymer electrolyte without SiO2 was firstly studied. Without DBP, the film is non-porous, and the conductivity is only 10-6S.cm-1. The film with DBP is micro-porous, and the conductivity increased to 10-4 S.cm-1. But it is not enough for the utility. And the film is non self-supporting.Both the self-supporting ability and the conductivity of the film with SiOi are increased. The improvement in the conductivity comes from two factors: for 2801, the addition of SiO2 changed the interaction between the Li+ ions and the matrix, resulting in the better conductivity; for LBG, it is because of the enlarged pore size and the higher pore ratio.