Design, fabrication and application of PEO/CMC-Li @PI hybrid polymer electrolyte membrane in all-solid-state lithium battery

Abstract

A novel PEO/CMC-Li @PI hybrid solid polymer electrolyte membrane was designed/assembled by utilizing the polyethylene oxide (PEO) as matrix, the modified N-carboxymethyl chitosan (CMC-Li) as the facilitator to accelerate the transport of lithium ions and the as-prepared polyimide (PI) non-woven fabric as supporting framework. The CMC-Li was firstly synthesized and then combined with PEO and PI non-woven fabric to assemble PEO/CMC-Li@PI membrane using in all solid-state battery (ASSB). The microscopic morphology of the PEO/CMC-Li@PI hybrid membrane was characterized by SEM images. The membranes thermodynamic behaviors were analyzed by the DSC/TG curves, showing that the Tm of the PEO/CMC-Li@PI decreased to 46.8 °C. When assembled into all-solid-state battery, the PEO/CMC-Li@PI membrane demonstrated the high ionic conductivities of 3.16 × 10–5 S/cm (30 °C) and 3.15 × 10–4 S/cm (60 °C) calculated from EIS spectra. The electrochemical window of the PEO/CMC-Li@PI cell was measured up to ~5 V at 60 °C. Moreover, the cell with PEO/CMC-Li@PI also delivered excellent electrochemical performances by comparing with other membranes. The high discharge capacities and cycling stability in PEO/CMC-Li@PI cell were assigned to the enhanced ionic conductivity by the added CMC-Li derivative and the improved mechanical properties by the PI non-woven fabric skeleton. The fabrication strategy of the novel PEO/CMC-Li@PI membrane may provide some new design directions for the solid polymer electrolytes in all-solid-state battery.