A Gum-like Electrolyte Promoting Safety and Performance of Lithium Ion Batteries

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The safety of lithium ion batteries has seen an increased concern with respect to the customers' usage, ground shipment and air transportation. Therefore, the next generation of these batteries must be safer in addition to high performance. The electrolyte is one of the key components in a battery. It plays a very important role for battery safety and performance. Currently, liquid electrolytes generally possess high ionic conductivity and good interfacial properties but come with safety issues. Solid polymer or inorganic solid electrolytes are essentially safe and show excellent mechanical properties. However, they have low ionic conductivity in comparison and poor interfacial contact/adhesion with electrodes, which limits their broad practical applications. Gel electrolytes are usually a combination of liquid and solid showing a promising type of high-performance electrolyte. However, several critical issues including safety concern and inferior mechanical performance still exist. Therefore, this study on a high performance electrolyte that will combine safety and beneficial properties of various electrolytes is significant and important for broad industry sectors, as well as further benefit the clean energy driven market.The objective of this project is to create a novel composite, gum-like (or gummy) material for electrolytes with the desired performance for next-generation energy storage devices including various lithium ion batteries. This gummy material possesses the following critical properties for electrolytes; high ionic conductivity at the liquid electrolyte level, strong adhesion to maintain good/stable contact with solid electrodes, good mechanical properties and the safety of solid material level. The design is based on a three-phase network composed or liquid component, (i.e. organic liquid electrolyte), solid particle component of thermally sensitive particles and soft matrix polar polymer. The optimized network formation will lead to the desired multi-functionalities for the gummy composite. The scope of the research includes: (1) investigation of the roles of the individual component in controlling the critical properties (conductivity, mechanical properties, adhesion etc.); (2) establishment of structure-property relationships for the gummy composite materials; (3) optimization of the compositions, structures and properties of the gummy composite for high performance electrolyte application. The intellectual merits of this project include: solving critical safety and interfacial problems for the electrolyte, introducing a new strategy for safety improvements in batteries especially thermal-protection capability; leading to a new approach to fabricate functional composite materials.