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Solid polymer electrolyte membranes (SPEMs) with star-shaped structure, consisting of octavinyl octasilsesquioxane (OV-POSS) with nanoscale organic/inorganic hybrid structure and poly(ethylene glycol) methyl ether methacrylate (PEGMEM), have been prepared by one-step free radical polymerization. OV-POSS with eight functional corner groups was used to produce star-shaped nanocomposites and PEGMEM was used as the polymer matrix to dissolve lithium ion. For comparison, SPEMs based on the corresponding linear copolymers, containing POSS moieties and PEGMEM segments, were also prepared. The SPEM with star-shaped structure containing 5.1 mol% POSS exhibits the highest ionic conductivity of 1.13×10 −4 S cm −1 and Li + transference number of 0.35 at 25 °C, which are about two times of that of SPEM with linear structure containing the same POSS content. Moreover, the Li/LiFePO 4 cell assembled with such star-shaped SPEM delivers the highest discharge capacity of 137.1 mAh g −1 under a current density of 0.5 C at 25 °C. At an evaluated temperature of 80 °C, this cell exhibits an initial discharge capacity of 163.8 mAh g −1 at 0.5 C, and even at high discharging C-rates of 5 and 10 C, the discharge capacity of 75.6 and 45.7 mAh g −1 can still be obtained, respectively. [ABSTRACT FROM AUTHOR]

A novel composite electrolyte membrane (CEM), consisting of a viscous PEGMEM-co-SMA copolymer, lithium salt and cellulose matrix, has been prepared as a new class of electrolyte for high performance lithium-ion batteries (LIBs). This CEM exhibits a wide electrochemical stability window (>5 V vs. Li/Li + ), reasonably high ionic conductivity and thermal stability up to 315 °C. At temperature above the melting temperature (31.98–35.71 °C), the viscous flow nature of the copolymer is beneficial to fully infiltrate the electrode materials like liquid electrolyte to maintain uniform contact with electrode surfaces during charge/discharge process. The interfacial resistance ( R intf ) of the fresh cell based on this CEM is extremely low (3.8 Ω cm −2 ) and the Li/LiFePO 4 cell deliveries a discharge capacity as high as 156.9 mA h g −1 with a current density of 1 C at 80 °C. It is anticipated that this work provides a new insight for designing advanced electrolyte materials for LIBs with enhanced interfacial contact and excellent cycling performance. [ABSTRACT FROM AUTHOR]