Lithiated nanosheets hybridized solid polymer electrolyte to construct Li+ conduction highways for advanced all-solid-state lithium battery

Abstract

Solid-state electrolyte is a key component of high-energy-density and security all-solid-state lithium metal battery. However, the present solid polymer electrolyte (SPE) often suffers from the trade-off between ionic conductivity and mechanical stability. To this end, lithiated polydopamine-modified graphene oxide nanosheets (LiDGO) are fabricated, and incorporated into the representative poly(ethylene oxide) (PEO) matrix to prepare hybrid solid polymer electrolyte (HSPE). Despite the decreased crystallinity of PEO, the intrinsic advantage of organic-inorganic hybridization affords PEO-based HSPE highly improved mechanical stability. The tensile strength and elongation at break of HSPE are, respectively, 237% and 133% higher than those of blank PEO. The constructed long-range conduction pathways with locally concentrated Li+ at PEO-LiDGO interfaces impart HSPE highly enhanced ionic conductivity. The ionic conductivity reaches 3.4 × 10−5 S cm−1 at 30 °C, 10 times higher than that of blank PEO. These then bring excellent battery performances. The assembled battery achieves a discharge capacity of ~156 mAh g−1 after 200 cycles with ultra-high capacity retention of 98.7%. The strategy of utilizing lithiated nanosheets to address the trade-off between ionic conductivity and mechanical stability of SPE may pave the way for the development of high performance all-solid-state lithium metal batteries.