(632h) Lithium Ion Conducting Multiblock Polymers As Solid-State Electrolytes for Lithium Ion Batteries
Lithium ion batteries are currently the leading commercial technology for portable electronic devices and electric vehicles. However, new solid polymer electrolytes (SPEs) that comprehensively possess the preferred properties of high ion conductivity, high electrochemical stability, robust mechanical properties, flexibility, and good film forming properties, are required to improve the safety and overall charge capacity and lifetime of lithium ion batteries. Although diblock copolymers have been explored as SPEs and can potentially provide the orthogonal properties of high ion conduction and high mechanical strength simultaneously in a solid-state material, there are limitations to diblock copolymer-salt mixture systems, such as a limited set of morphologies, and a lack of means to achieve simultaneous combination of more than two properties (e.g., conductivity, strength, flexibility). Compared to diblock copolymers, multiblock polymers involve more than two polymer chemistries and therefore enable the possibility to conjoin many of the desired properties, such as high ion conductivity, mechanical strength, flexibility, good film forming properties, processability, and high electrochemical stability all into a single platform. In this study, a lithium ion conducting multiblock copolymer was synthesized and explored as an SPE for lithium ion batteries. Specifically, an ABCBA pentablock terpolymer-salt mixture system was explored. The morphology, chemical, thermal, mechanical, and electrochemical properties were examined as function of block polymer composition, cation chemistry, and film processing conditions. Lithium ion battery performance of these pentablock terpolymers as SPEs was also examined. Overall, this work provides the first evaluation of pentablock terpolymers as SPEs for batteries and the opportunity to integrate multiple desired properties into SPEs.