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

锂离子电池的安全性在客户的使用、地面运输和空运方面受到了越来越多的关注。因此，下一代这些电池除了高性能外，还必须更安全。电解液是电池的关键部件之一。它对电池的安全和性能起着非常重要的作用。目前，液体电解质一般具有较高的离子导电性和良好的界面性能，但也存在安全问题。固体聚合物或无机固体电解质基本上是安全的，并显示出优异的机械性能。然而，它们的离子导电性较低，与电极的界面接触/附着力较差，限制了其广泛的实际应用。凝胶电解质通常是液体和固体的混合物，是一种很有前途的高性能电解质。然而，仍然存在一些关键问题，包括安全问题和机械性能较差。因此，研究一种结合各种电解液的安全和有益性能的高性能电解液，对于广泛的工业部门以及进一步惠及清洁能源驱动的市场具有重要的意义。本项目的目标是为包括各种锂离子电池在内的下一代储能设备创造一种新型的复合、胶状(或胶状)电解液材料。这种胶状材料具有以下电解质的关键性能：液体电解质水平的高离子导电性，与固体电极保持良好/稳定接触的强大附着力，良好的机械性能和固体材料水平的安全性。该设计基于由液体组分(即有机液体电解质)、热敏粒子的固体粒子组分和软基极性聚合物组成的三相网络。优化的网络形成将为胶体复合材料带来所需的多功能。研究的范围包括：(1)研究单个组分在控制关键性能(导电性、力学性能、附着力等)中的作用；(2)建立胶体复合材料的结构-性能关系；(3)高性能电解液应用的胶体复合材料的组成、结构和性能的优化。该项目的智能优点包括：解决了电解液的关键安全和界面问题，引入了一种新的策略来提高电池的安全性，特别是热保护能力；导致了一种制造功能复合材料的新方法。

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.