Supramolecular Salt-Assisted Quasi-Solid-State Electrolyte Promoting Dual Conductive Interface for High-Energy-Density Lithium Metal Batteries

Ion electrokinetic regulation in gel polymer electrolytes (GPEs) is of great significance in alleviating dendrite growth and electrode corrosion of metallic lithium in lithium metal batteries (LMBs). Herein, a supramolecular LiPAAOB salt-assisted GPEs (3D-DIS-1.25% GPEs) is synthesized to improve the ionic electrodynamics of LMBs. The LiPAAOB conductor salt provides sufficient Li+ ions while simultaneously facilitating LiTFSI dissociation. Theses dissociated Li+ ions can be further anchored firmly by enriched affinitive sites (CO, CO) induced in 3D composite polymer skeleton (PALC). Due to the strong hydrogen-bonding interactions between PALC and LiPAAOB/LiTFSI, a stable coordination structure is thereby constructed in 3D-DIS-1.25% GPEs, which then facilitates Li+ ions to transport rapidly along polymer chains. Consequently, the electrochemical stable window and ionic conductivity of the 3D-DIS-1.25% GPEs are increased to as high as 5.3 V and 1.34 mS cm-1, respectively. The Li+/e- double conducting interfaces in situ formed on Li metal anode and active particles in cathodes can effectively inhibit dendrite growth and electrode corrosion. As a result, both Li||3D-DIS-1.25% GPEs||Li symmetrical battery and flexible 3D-DIS-1.25% GPEs-based pouch cell with high LFP loading operate stably even under folded and curly state, indicating the application possibility of using 3D-DIS-1.25% GPEs in constructing various flexible high-energy-density batteries. The modulating effects of supramolecular LiPAAOB salt and 3D PALC polymer host on enhancing intermolecular interactions and promoting the ordered transport of Li+ ions in quasi-solid-state polymer electrolyte are systematically investigated. Both 3D polymer host and supramolecular LiPAAOB provide enriched affinitive sites that can firmly anchor and direct the transport of dissociated Li+ ions, further forming compact SEI/CEI interface layers.image

Automated summary

This study investigates the modulation effects of supramolecular LiPAAOB salt and 3D PALC polymer host on enhancing intermolecular interactions and promoting the ordered transport of Li+ ions in quasi-solid-state polymer electrolyte. The synthesized LiPAAOB-assisted GPEs show improved electrochemical stable window and ionic conductivity, effectively inhibiting dendrite growth and electrode corrosion, and demonstrating potential application in constructing flexible high-energy-density batteries.