Preparation and performance characterization of polymer Li-ion batteries using gel poly(diacrylate) electrolyte prepared by in situ thermal polymerization

摘要

A gel polymer electrolyte (GPE) was prepared by in-situ thermal polymerization of 1,3-butanediol diacrylate (BDDA) in a EC/EMC/DMC electrolyte solution at 100 degrees C. The GPE with 15 wt.% polymer content appears as apparently "dry" polymer with sufficient mechanical strength and shows a high ionic conductivity of 3.2x10(-3) S cm(-1) at 20 degrees C. The MCMB-LiCoO2 type polymer Li-ion batteries (PLIB) prepared using this in-situ internal polymerization method exhibit a very high initial charge-discharge efficiency of 92.1%, and can deliver 94.4% of its nominal capacity at 1.0 C rate and 70.7% of its room temperature capacity at -20 degrees C. Also, the PLIB cells show very good cycling ability with > 85% capacity retention after 300 cycles. The excellent charge-discharge properties of the PLIB cells are attributed to the integrated structure in which the polymer matrix spreads over entire region of the cell acting as a strong binder and electrolyte carrier to produce a stabilized electrode-electrolyte interface. In addition, the fabricating process of the polymer cell is quite simple and convenient for practical applications.