d 8-poly(methyl methacrylate)-poly[(oligo ethylene glycol) methyl ether methacrylate] tri-block-copolymer electrolytes: Morphology, conductivity and battery performance

摘要

AbstractA series of deuterated tri-block copolymers with the general structure d8-PMMA-POEGMA-d8-PMMA, with variation in d8-PMMA chain length, were synthesized using sequential controlled radical polymerization (ATRP). Solid polymer electrolytes (SPEs) were produced by blending tri-block copolymers and lithium bis(trifluoro methylsulfonate) (LiTFSI). Small-angle neutron scattering (SANS) was used to study the bulk morphology of the deuterated tri-block copolymer electrolyte series at 25?°C, 60?°C and 95?°C. The lack of a second Tgin DSC analysis together with modelling with the random phase approximation model (RPA) confirmed that the electrolytes are in the mixed state, with negative Flory-Huggins interaction parameters. AC impedance spectroscopy was used to study the ionic conductivity of the SPE series in the temperature interval 30?°C–90?°C, and a battery device was constructed to evaluate a 25?wt% d8-PMMA electrolyte. The Li | SPE | LiFePO4cell cycled at 60?°C, giving a discharge capacity of 120?mAh g?1, while cyclic voltammetry showed that the SPE was stable at 60?°C.Graphical abstractDisplay Omitted<