Metal-Organic Framework-Coated Fiber Network Enabling Continuous Ion Transport in Solid Lithium Metal Batteries

Poly(ethylene oxide) (PEO)-based solid-state polymerelectrolytes(SPEs) have limited application in lithium metal batteries due totheir low room-temperature ionic conductivity and high interfacialimpedance with electrodes. Constructing efficient enhancers is a promisingway to tackle these critical issues, but still remains a huge challenge.In this study, a continuous and hierarchical lithium-ion transportnetwork was constructed by growing a copper-based metal-organicframework (MOF) (Cu-MOF-74) on a three-dimensional (3D) nonwovenfabric (NWF). The incorporation of the high-surface-area NWF effectivelyprevents MOF particle agglomeration, thereby creating a 3D interconnectednetwork of ion transportation channels that span both vertically andlaterally. Additionally, MOF nanoparticles with functional groupsexhibit a high affinity toward bis(tri-fluoromethanesulfonyl) imideanions, which is facilitated by hydrogen bonding between oxygen-containingfunctional groups and fluorine, as well as metal-oxygen bonds,releasing more free lithium ions. The as-prepared electrolyte exhibitsa fast ionic conductivity of 1.0 x 10(-4) S cm(-1) at 30 & DEG;C, a high lithium-ion transference numberof 0.39, and a wide electrochemical window of 4.9 V. The all-solid-stateLi-LiFePO4 cells possess a high initial dischargecapacity of 160.4 mAh g(-1) at 0.5C, excellent rateperformance (specific capacity reached 148.6 mAh g(-1) at 2.0C), and good cycle stability. This approach presents a cost-effectiveand efficient strategy for enhancing PEO-based SPEs, providing a promisingdirection for overcoming the challenge of low ionic conductivity inall-solid-state lithium metal batteries.