A Li-based MOF-derived multifunctional PEO polymer solid-state electrolyte for lithium energy storage

Abstract

A three-dimensional (3D) metal–organic framework containing Li-oxygen clusters, namely {[Li₂(IPA)]·DMF}_n (1) (H₂IPA = isophthalic acid), has been constructed under solvothermal conditions. The Li-based MOF can be applied to lithium energy storage. For example, it shows good compatibility with a PEO (LiTFSI) solid-state polymer electrolyte (SSPE). The PEO (LiTFSI) with the MOF additive shows an ionic conductivity of 1.1 × 10⁻⁵ S cm⁻¹ at room temperature. The 1D rhombic channels should facilitate lithium ion transportation and provide fast lithium ion pathway. Having assembled the PEO-MOF SSPE in a Li/Li symmetric cell and cycled at a current density of 0.1 mA cm⁻², the polarization voltage was below 0.1 V during a 100 h test. The PEO-MOF SSPE was also used in a LiFePO₄-Li full cell and a high specific capacity of 144 mA h g⁻¹ was achieved.