Solid electrolyte (SE) is the most crucial factor to fabricate safe and high-performance all-solid-state lithium-ion batteries. However, the most commonly reported SE, including solid polymer electrolyte (SPE) and inorganic oxides and sulfides, suffer problems of low ionic conductivity at room temperature for SPE and large interfacial impedance with electrodes for inorganic electrolytes. Here we for the first time demonstrate a novel ionic plastic crystal lithium salt solid electrolyte (OLiSSE) fast ion-conductor dilithium (1,3-diethyl-4,5-dicarboxylate) imidazole bromide with ordered Li-ion conductive nanopathways and an exceptional ionic conductivity of 4.4 × 10⁻³ S cm⁻¹ at 30 °C. The prepared OLiSSE exhibits apparent characters of typical ionic plastic crystals in the temperature range of −20–70 °C, and shows remarkable thermal stability and electrochemical stability below 150 °C and 4.7 V, respectively. No lithium dendrite or short circut behavior is detected for the Li|OLiSSE|Li cell after the galvanostatic charge-discharge test for 500 h. The fabricated Li|OLiSSE|LiFePO₄ all-solid-state cell without using any separator and liquid plasticizer directly delivers an initial discharge capacity of 151.4 mAh g⁻¹ at the discharge rate of 0.1 C, and shows excellent charge-discharge cycle stability, implying large potential application in the next generation of safe and flexible all-solid-state lithium batteries.

固体电解质（SE）是制造安全、高性能的全固态锂离子电池最关键的因素。然而，最常报道的SE，包括固体聚合物电解质（SPE）和无机氧化物和硫化物，存在SPE在室温下离子电导率低和无机电解质电极界面阻抗大的问题。在这里，我们首次展示了一种新型离子塑料晶体锂盐固体电解质 (OLiSSE) 快速离子导体二锂（1,3-二乙基-4,5-二羧酸）咪唑溴化物，具有有序的锂离子导电纳米通路和特殊的离子电导率为 4.4 × 10 ^-3 S cm ^-1在 30°C。制备的OLiSSE在-20-70°C的温度范围内表现出典型的离子塑料晶体的明显特征，并分别在150°C和4.7 V以下表现出显着的热稳定性和电化学稳定性。Li|OLiSSE|Li 电池在恒流充放电测试 500 小时后未检测到锂枝晶或短路行为。所制备的Li|OLiSSE|LiFePO ₄全固态电池不使用任何隔膜和液体增塑剂，在0.1 C的放电倍率下直接提供151.4 mAh g ^-1的初始放电容量，并表现出优异的充放电循环稳定性，这意味着在下一代安全灵活的全固态锂电池中具有巨大的应用潜力。