A promising composite room temperature solid electrolyte via Incorporating LLZTO into Cross-linked ETPTA/PEO/SN matrix for all solid state lithium batteries

Abstract Composite solid electrolyte (CSE), especially the composite room temperature solid electrolyte (CRTSE), is emerging as the promising electrolyte for all-solid-state lithium batteries (ASSLB) due to their ability to combine the desirable properties of ceramic and polymer-based electrolytes, and the room temperature operation condition. In this paper, the CRTSE with polyethylene oxide (PEO), Bis (fluorosulfonyl)imide (LiTFSI), Succinonitrile (SN), LLZTO inorganic fillers and cross-linked ethoxylated trimethylolpropane triacrylate (ETPTA) was proposed. With the help of the suppression dendrite growth of lithium via cross-linked microscopic pore structure, enhancement of the ionic conductivity via LLZTO fillers, wide electrochemical window via SN, the obtained CRTSE shown high ionic conductivity (2.12 × 10-4 S cm-1), high Li+ transfer number (tLi+=0.55), stable electrochemical window (5.0 V vs Li/Li+) at room temperature. The Li symmetrical cell can cycle over 500 hours stably with current density of 0.1 mA cm-2 and 0.5 mA cm-2 at room temperature. The full solid state LiFePO4 cell can successfully work over 200 cycles with capacity retention ratio of about 70% at room temperature.