Although the idea of replacing liquid electrolytes in lithium batteries with solid electrolytes has been accepted by many people, there are still many difficulties to overcome before the technology can be put into practice. The good news is that a team at Brown University has produced the toughest solid electrolyte to date by mixing a fine mixture of ceramics and graphene.
Electrochemical properties of LATP/rGO nanocomposites (from: Science Direct)
Liquid electrolytes play an important role in today’s lithium-ion batteries as solutions that carry lithium-ions back and forth between anodes and cathodes during battery charge and discharge.
However, these highly volatile liquids are also at risk of fire when the battery is shorted, so there is still room for improvement in safety. Alternative electrolytes also help increase the energy density of the battery and even upgrade other components of the battery.
A recent study suggested that anodes are usually made of copper and graphite, but scientists believe solid electrolytes can work together with pure lithium anodes to break the “energy density bottleneck.”
Unfortunately, this work is not simple, and the problem is mainly that other parts of the battery may break and corrode. Although ceramics are durable enough, their physical properties are too brittle.
rGo helps prevent cracks in the battery from spreading (Photo: Brown University)
With this in mind, the Brown University team considered adding a small amount of graphene to it. But as a wonderful material that is both sturdy and lightweight, it also has a high conductivity and must be carefully utilized.
Study author Nitin Padture said: We want electrolytes to transmit ions, not conduct electricity. Graphene is a good conductor, so people may think we put a conductor in a conductor.
But if we keep the concentration low enough, we can stop graphene from conducting electricity while still enjoying the benefits of its structural properties.
It is reported that the research team will be a certain amount of graphene oxide (rGo) thin sheet and ceramic powder mixed, and then heat the mixture to form ceramic-graphene composite materials.
Demo: Performance Improvements
After testing, the team demonstrated that ceramic toughness alone can be doubled, and graphene does not interfere with the other electrical properties of this electrolyte material.
When cracks occur in the material, graphene sheets can actually hold the fractured surface together, requiring more energy to tear it apart, Says Athanasiou.
As the strongest man-made solid electrolyte to date, we hope to use further research to put it into everyday equipment.
Details of the study have been published in the recently published issue of The Materials.
Originally published as High-Toughness Inorganic Solid Pros via the Use of Reduced Graphene Oxide.