DEVELOPMENT AND RESEARCH OF COMPOSITE ELECTROLYTE BASED ON LATP/LIPF6 SYSTEM FOR LITHIUM BATTERIES

Abstract

Electrochemical power sources (EPSs) have been an integral part of every modern person’s life for a long time. Lithium-ion batteries (LIB) are the most common among the modern EPSs. They are widely used in the various electronic devices such as smartphones, cameras, laptops, electric vehicles etc. LIBs are considered to be the best power sources for mass use due to their high energy density. However, the low level of safety has always been a weakness of the conventional lithium-ion batteries with a polymer separator impregnated with a liquid electrolyte. The paper shows the fundamental possibility to develop the lithium-ion batteries with a composite electrolyte based on a porous ceramic matrix LATP, impregnated with 1M solution of LiPF6 in a mixture of ethylene carbonate and dimethyl carbonate (1:1). Two samples of composite electrolyte of different thickness (0.8 mm and 1.6 mm) were produced. The specific capacity of the cathode material in the elements with a composite electrolyte equals 140.5 and 138.2 mAh/g, which is not significantly less than the corresponding value for the cells with a liquid electrolyte (145.6 mAh/g). The decrease in the capacity of the cathode material in the elements with a composite electrolyte is primarily connected with the non-optimal thickness of the ceramic electrolyte and, accordingly, with the increase in the internal resistance of the cell. It is established that prototypes of lithium-ion batteries with a composite electrolyte show higher stability of capacitive characteristics during long cycling. Also, the proposed composite electrolyte allows solving the problems of lithium-ion batteries associated with electrolyte leakage (liquid electrolyte is immobilized only in the pores of ceramics) and fire hazard, primarily by levelling the formation of lithium dendrites in the interelectrode space. Further research will be aimed at the reducing the thickness of the ceramic electrolyte and developing a process for applying a protective layer to eliminate the recovery of LATP with lithium metal.