Preparation of High Toughness Inorganic Solid Electrolyte by Reduced Graphene Oxide

In recent years, solid electrolytes have been rapidly developed for lithium ion batteries. Among them, the ceramic electrolyte used in lithium-ion batteries has the characteristics of good safety, low cost, environmental friendliness and wide operating temperature range, and has good application prospects in large-scale power lithium-ion batteries with high specific energy.

However, ceramic solid electrolytes have the disadvantages of poor mechanical strength, brittleness, and large changes in ion transmission channels when the temperature changes. In order to overcome these shortcomings and improve the fracture resistance of ceramic materials, a research team at Brown University in the United States reported on the use of reduced oxidation Graphene to enhance the toughness of oxide-based lithium ion conductive conductors, and a method for preparing high-toughness inorganic solid electrolytes.

The researchers were inspired by the toughening effect of reduced graphene oxide on polymers and engineering ceramics. Using a small amount of reduced graphene oxide to enhance the ceramic solid electrolyte can significantly improve its fracture toughness, while the ion conductivity changes little. The experimental results show that the toughness of Li1+xAlxTi2-x(PO4)3 (LATP) has more than doubled, with the highest low fracture toughness (KIc) value reported for inorganic solid electrolytes. This method can not only improve the ionic conductivity of the material and improve the mechanical stability of the material, but also effectively prevent the electronic conduction, and overcome the defects of the ceramic membrane that the temperature of the ion channel is unstable.

There are many types of ceramic solid electrolytes. From the structural point of view, they mainly include NASICON structured lithium ceramic electrolytes, perovskite type lithium ceramic electrolytes, LISICON type lithium ceramic electrolytes, Li3N type lithium ceramic electrolytes, lithiated BPO₄ lithium conductive ceramic electrolytes and Li₄SiO₄ is the mother's lithium ceramic electrolyte and so on. The researchers analyzed the chemical mechanical behavior of these materials to provide guidelines for the design of strong and tough electrolytes that can resist lithium metal penetration.

References: Christos E. Athanasiou, et al, High-Toughness Inorganic Solid Electrolytes via the Use of Reduced Graphene Oxide, Matter (2020) DOI: 10.1016/j.matt.2020.05.003