Characteristics of new-type solid polymer electrolyte controlling nano-structure

Both high ionic conductivity and excellent mechanical properties are required to solid polymer electrolytes (SPEs) for all-solid lithium polymer batteries. We synthesized a solid polymer electrolyte with micro phase separation structure and its electrochemical characteristics were investigated. The highest value of ionic conductivity was obtained at a concentration of 5 mol% of lithium salt to ethyleneoxide unit ([EO]). The ionic conductivity of this SPE was 2 × 10−4 S cm−1 at 30 °C. An all-solid state lithium polymer battery, Li/SPE/Li CoO2 composite cathode cell, exhibited an excellent charge/discharge character with keeping a discharge capacity of 100 mAh g−1 after 100 cycles at room temperature. This SPE was electrochemically stable and did not decompose up to 4.5 V.