Polymer electrolytes shielded by 2D Li0.46Mn0.77PS3 Li+-conductors for all-solid-state lithium-metal batteries

The development of solid polymer electrolytes (SPEs) is impeded by the severe Li-dendrites growth at the unstable SPE-Li interface. Herein, we demonstrate that the interfacial stability of poly(ethylene oxide) (PEO) electrolytes against Li metal is significantly improved by a shielding strategy, where the nanosheets of a 2D Li + conductor Li 0.46 Mn 0.77 PS 3 (LiMPS) serve as nanosized shields to armor PEO against the spears - lithium dendrites . Besides physical inhibition, LiMPS also homogenizes Li + flux owing to its 2D nature, superior Li + conductivity (2.1 × 10 −4 S cm −1 at 30 ℃) and strong adsorption of Li + . This strategy also enables PEO-LiMPS electrolytes to exhibit superior ionic conductivity of 2.6 × 10 −4 S cm −1 at 45 ℃, a nearly tenfold increase compared to bare PEO electrolytes. Furthermore, the electrochemical stability window (ESW) of PEO-LiMPS electrolytes is expanded to 4.8 V (3.8 V for pristine PEO). As a result, symmetric Li/PEO-LiMPS/Li cells deliver short circuit-free cycling over 600 h, and LiNi 0.8 Co 0.1 Mn 0.1 O 2 /PEO-LiMPS/Li batteries also present a high-capacity retention over 80% after 200 cycles at 0.2 C. In addition, LFP/PEO-LiMPS/Li pouch cell retains 93% of the initial capacity after cycling at 0.2 C for 230 cycles. This 2D Li + -conductive shielding strategy provides a unique protective mechanism for SPEs in solid-state Li metal batteries (SSLMBs).