Composite solid electrolyte PEO/SN/LiAlO2 for a solid-state lithium battery

Lithium aluminate (LAO) is known to be an effective filler for improving the conductivity of polyethylene–LiX (PEO–LiX) solid polymer electrolytes (SPEs), while succinonitrile (SN) is an excellent solid plasticizer with plastic crystalline organic molecules. In this work, LAO micro-rods are prepared via a simple hydrothermal method, and a novel PEO-based composite polymer electrolyte is developed by the addition of SN and LAO. The resulting optimal composite PEO:LiTFSI:SN(15%):LAO(10%) (PEOL-SPE) has a maximized ionic conductivity of 1.36 × 10−5 S·cm−1at 30 °C, and the membrane has a wide electrochemical window of 5.2 V. The fabricated cell with LiFePO4 as the cathode, metallic lithium as the anode and PEOL-SPE as the electrolyte membrane delivers an impressive initial charge/discharge capacity of 153.1/141.3 mAh g−1 at 60 °C. The addition of 10 wt% of the LAO micro-rods results in a favorable increase in the ionic conductivity, and no apparent blocking effect is observed to impede the electrochemical performance. These results bring to light the potential of micro-sized additives for use in lithium battery applications.