Cross-linked branching nanohybrid polymer electrolyte with monodispersed TiO2 nanoparticles for high performance lithium-ion batteries

Nanohybrid polymer electrolytes (NHPE) with ceramic particles have attracted significant attention owing to their improvement in electrochemical performance. However, particle aggregation and weak nanoparticle/polymer matrix interaction restrict their further application in lithium-ion batteries (LIBs). We demonstrate a facile in-situ polymerization/crystallization method to synthesize a homogeneous TiO 2 -grafted NHPE with a cross-linked branching structure, comprised of ion-conducting poly(ethylene glycol) methyl ether methacrylate (PEGMEM) and non-polar stearyl methacrylate (SMA). This technique is different from existing methods of blending functionalized ceramic particles into the polymer matrix . Highly monodispersed TiO 2 nanocrystals enhance the effective interfacial interactions between particles and polymer matrix , which suppress the crystallization of ethylene oxide (EO) groups and facilitate forming continuously interconnected ion-conducting channels. Moreover, an increased dissociation degree of Li salt can also be achieved. The TiO 2 -grafted NHPE exhibits superior electrochemical properties with an ionic conductivity of 1.1 × 10 −4  S cm −1 at 30 °C, a high lithium ion transference number and excellent interfacial compatibility with the lithium electrode. In particular, a lithium-ion battery based on TiO 2 -grafted NHPE demonstrates good C-rate performance, as well as excellent cycling stability with an initial discharge capacity of 153.5 mAh g −1 and a capacity retention of 96% after 300 cycles at 1 C (80 °C).