A single lithium-ion conducting solid polymer electrolyte with superior electrochemical stability and interfacial compatibility for solid-state lithium metal battery

Lithium metal batteries are being explored in meeting ever-increasing energy density needs. Because of serious dendritic lithium issues in liquid-state electrolytes, it is generally thought that solid-state electrolytes are the potential alternatives for lithium metal batteries. Herein, we design a new single lithium-ion conducting lithium poly[(cyano)(4-styrenesulfonyl)imide] (LiPCSI) to replace the conventional dual-ion conducting salt in use of solid polymer electrolytes (SPEs) that successfully suppress the growth of lithium dendrites. Owing to highly delocalized anion moiety and oxidation-resistant cyano group, the tailored PEO8−LiPCSI SPE exhibits extremely high Li+ transference number (0.84) as well as oxidation potential (5.53 V vs Li+/Li). The symmetric Li/PEO8−LiPCSI/Li cell runs for 1000 h at 60 °C without short circuit. The rechargeable solid-state Li/PEO8−LiPCSI/LiFePO4 cell discharges a capacity of 141 mAh g−1 with the retention over 85% during 80 cycles. These merits enable the proposed PEO...