| 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 largeinterfacial impedance with electrodes for inorganic electrolytes.In order to obtain a high-performance solid-state lithium-ion electrolyte with high ionic conductivity,electrochemical stability window,thermal stability,and lithium-ion transport number,this work uses 4,5-imidazole dicarboxylic acid,bromoethane,iodoethane,lithium hydroxide as the main raw material,designed and synthesized an organic lithium salt solid electrolyte（Olisse）with plastic crystal properties;at the same time,combined with the ordered structure of organic-inorganic perovskite and its excellent electrical and optical properties,using the synthesized Olisse as the monovalent cation moiety in organic-inorganic perovskites,synthesized an organic-inorganic perovskite-type all-solid-state lithium-ion battery electrolyte（PVK）.And systematically characterized its physical and chemical properties,the specific conclusions are as follows:（1）Olisse is a partially melted/softened organic ionic plastic crystal with a highly ordered structure at room temperature.After heating and melting into an amorphous state,the ordered crystalline structure can be rearranged by cooling down.Through XRD test,we found that the crystallinity of Olisse is above 40%,and the highest Olisse-Br is 99.9%;PVK with Olisse as synthetic raw material has the same plastic crystal properties as Olisse,and the crystallinity is not less than 40%;（2）Using Olisse-Br as a template to Materials Studio modeling,the mechanism of fast conduction of lithium ions in highly ordered structures was analyzed;（3）The initial thermal decomposition temperature of Olisse is around 130℃.Benefiting from the organic-inorganic perovskite structure,PVK has improved thermal stability compared to Olisse,with an initial decomposition temperature of 160℃.The thermal stability of both can meet the requirements of solid electrolytes;（4）The electrochemical stability windows of Olisse and PVK are both above 4 V,meet the voltage range of lithium-ion batteries;（5）The plastic crystal ion conduction channel constructed by Olisse and the organic-inorganic perovskite conduction channel constructed by PVK obtained considerable ionic conductivity and lithium ion migration number.At 30℃,the highest conductivity of Olisse-Br is 4.35×10-3 S/cm,the lowest conductivity of Olisse-I is1.6×10-5 S/cm,and the conductivity of PVK is 10-4 S/cm.At the same time,the lithium ion migration number t Li+of Olisse and PVK are both above 0.50,which is higher than the traditional lithium ion solid electrolyte;（6）Olisse and PVK exhibited good cycling stability and electrode compatibility.The electroplating-stripping test was carried out at 30℃and a current density of 1m A/cm2 for 500 h,and no short circuit occurred during the test,indicating that the developed electrolyte can inhibit the growth of lithium dendrites.The results of electron probe microscopy morphology analysis showed that the lithium flakes,Olisse and PVK did not change much before and after cycling,and the growth of lithium dendrites and the decomposition of the electrolyte were not observed.（7）Li/Olisse-Br/LiFePO4 battery has an initial discharge capacity of 151.4m Ah/g at a rate of 0.1 C,and a capacity of 148.9 m Ah/g after 120 cycles at a rate change of 0.1-2 C,showing good charging performance.Discharge cycling stability and Coulombic efficiency. |
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