TiO 2 inorganic nanoparticle framework enhanced PEO based solid-state electrolytes for improved performance of solid-state lithium batteries

Abstract

Abstract Solid-state batteries with poly(ethylene oxide) (PEO) solid electrolytes are considered to have a wide range of application prospects. However, the high-level crystallinity of PEO leads to poor lithium-ion conduction capability, and there are problems such as poor electrochemical stability and undesirable contact characteristics of electrode/electrolyte interface in solid-state lithium batteries. In order to solve these problems, composite polymer electrolytes (CPE) containing TiO2 as inorganic frameworks are prepared by a facile solution casting method in this paper. The results show that the CPE with TiO2 content of 10 wt% elevates the conductivity to 1.08 × 10− 3 S cm− 1 at 60°C as one of the best polymer composite solid electrolytes. The Li symmetric battery with constant current charge/discharge cycle test at 0.2 mA˖cm− 2 current density stabilizes the cycle for 129 h. The initial specific capacity of LiFePO4/PLT10/Li at 0.1 C reaches 133.01 mAh˖g− 1 with a coulombic efficiency of 83.44%. The discharge specific capacity remains 152.52 mAh˖g− 1 with a cyclic retention of 109.51% for capacity after 20 cycles at 0.1 C. The oxidation/reduction peaks potential difference on the cyclic voltammetry curves (CV) is 0.483 V. As expected, the TiO2 inorganic framework reduces the crystallinity of the PEO-based solid electrolytes and improves solid-state electrolyte and interfacial stability in Li-ion batteries, which bring higher coulombic efficiency and cycling capacity retention.