Single-Ion Polymer Electrolyte Based on Lithium-Rich Imidazole Anionic Porous Aromatic Framework for High Performance Lithium-Ion Batteries.

The low ionic conductivity and Li transference number ( ) of solid polymer electrolytes (SPEs) seriously hinder their application in lithium-ion batteries (LIBs). In this study, a novel single-ion lithium-rich imidazole anionic porous aromatic framework (PAF-220-Li) is designed. The abundant pores in PAF-220-Li are conducive to the Li transfer. Imidazole anion has low binding force with Li . The conjugation of imidazole and benzene ring can further reduce the binding energy between Li and anions. Thus, only Li moved freely in the SPEs, remarkably reducing the concentration polarization and inhibiting lithium dendrite growth. PAF-220-quasi-solid polymer electrolyte (PAF-220-QSPE) is prepared through solution casting of Bis(trifluoromethane)sulfonimide lithium (LiTFSI) infused PAF-220-Li and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP), and possessed excellent electrochemical performance. The electrochemical property are further improved by preparing all-solid polymer electrolyte (PAF-220-ASPE) via pressing-disc method, which has a high Li conductivity of 0.501 mS cm and of 0.93. The discharge specific capacity at 0.2 C of Li//PAF-220-ASPE//LFP reached 164 mAh g , and the capacity retention rate is 90% after 180 cycles. This study provided a promising strategy for SPE with single-ion PAFs to achieve high-performance solid-state LIBs.