Controllable magnetic field aligned sepiolite nanowires for high ionic conductivity and high safety PEO solid polymer electrolytes

Abstract

Poly (ethylene oxide) (PEO) polymer electrolyte, attracts great attention owing to its excellent flexibility, good processability and high safety compared with liquid electrolytes. However, its low ionic conductivity and weak ability to suppress the lithium dendrite severely restrict the further progress of PEO. Herein, we prepare a high ionic conductivity solid polymer electrolyte for all-solid-state lithium batteries by mixing PEO and magnetically aligned functionalized sepiolite (KFSEP) nanowires. The ionic conductivity of PEO/LiTFSI/10%⊥KFSEP solid polymer electrolyte is 2.0 × 10−5 S cm−1 at 20 °C (The ionic conductivity of PEO/LiTFSI solid polymer electrolyte is 4.0 × 10−7 S cm−1 at 20 °C). The experiments and simulation analysis indicate that the aligned nanowires provide a fast-moving channel for lithium ions. The capacity of Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell is 130 mAh g−1 at 1.0 C under 60 °C after 450cycles. Furthermore, Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell shows 150 mAh g−1 at 0.2 C under 25 °C. The Li/PEO/LiTFSI/10%⊥KFSEP/Li cell can work normally more than 600 h, indicating the high stability and lithium dendrite suppressing function of PEO/LiTFSI/10%⊥KFSEP. Overall, a high performance solid polymer electrolyte with higher safety is constructed by incorporating magnetically aligned sepiolite nanowires into PEO.