A highly ionic conductive poly(methyl methacrylate) composite electrolyte with garnet-typed Li6.75La3Zr1.75Nb0.25O12 nanowires

Abstract

Composite solid polymer electrolytes, integrating advantages (inflammability and electrochemical stability) of inorganic parts and virtues (lower interfacial resistance, flexibility and handy preparation) of polymer matrix, present a promising prospect for safe high-energy solid-state lithium energy storage systems. Herein, one-dimensional garnet-typed Li6.75La3Zr1.75Nb0.25O12 nanowires are successfully synthesized, and the nanowires are complexed with poly(methyl methacrylate), lithium perchlorate to fabricate composite solid polymer electrolyte membranes via a facile solution-casting method. The ionic conductivity is sharply increased from 5.98 × 10−7 of filler-free solid electrolyte to 2.20 × 10−5 S cm−1 of composite solid polymer electrolyte at room temperature, because the interaction between nanowires and polymer chains provide more free volume and special ionic conductive channels. In the meantime, the composite solid polymer electrolytes exhibit the wide electrochemical window and good stability against lithium anode. The feasibility of composite solid polymer electrolyte is examined in LiCoO2/Li configuration at 0.2 C under 60 and 70 °C, the cells deliver discharge capacity of 134.6 and 143.6 mAh g−1 at first cycle and kept 92.3%, 71.8% retention after 80 and 65 cycles respectively. The results indicate that the as-prepared composite solid polymer electrolytes will be a promising candidate for solid-state lithium batteries in the future.