Although the idea of using solid electrolytes to replace liquid electrolytes in lithium batteries has been accepted by many people, there are still many difficulties to overcome before this technology is put into practical use. The good news is that a research team at Brown University has produced the toughest solid electrolyte to date by incorporating a fine mixture of ceramic and graphene.
As a solution that carries lithium ions back and forth between the anode and the cathode during battery charging and discharging, liquid electrolytes play an important role in today's lithium ion batteries.
However, these highly volatile liquids also have the risk of causing a fire when the battery is short-circuited, so there is still much room for improvement in safety. In addition, replacing the electrolyte also helps to increase the energy density of the battery and even upgrade other components of the battery.
A recent study pointed out that the anode is usually made of copper and graphite, but scientists believe that solid electrolytes can work with pure lithium anodes to break the "energy density bottleneck." Unfortunately, this work is not simple, the current problem is mainly reflected in the other parts of the battery may be cracked and corroded. Although ceramic is durable enough, its physical properties are too brittle.
Graphene oxide (rGo) helps prevent the crack propagation of ceramic materials in the battery
In view of this, the Brown University research team considered adding a small amount of graphene to it. But as a wonderful material that is both strong and lightweight, it also has a high electrical conductivity, so these properties must be used carefully.
Research author Nitin Padture said: We want the electrolyte to transfer ions, not conduct electricity. Graphene is a good electrical conductor, so people might think that we put a conductor in a conductor. But if we can keep the concentration low enough, we can prevent graphene from conducting electricity while still enjoying the benefits of its structural properties.
It is reported that the research team mixed a certain amount of graphene oxide (rGo) fine flakes with ceramic powder, and then heated the mixture to form a ceramic-graphene composite material.
Through testing, the team proved that only ceramic toughness can be increased by two times, and graphene does not interfere with other electrical properties of this electrolyte material.
Athanasiou said: When cracks appear in the material, graphene sheets can actually hold the broken surfaces together, so more energy is needed to tear them apart. As the strongest man-made solid electrolyte so far, we hope that through further research, it can be put into daily use equipment.
The details of this research have been published in the recently published "Materials" (Materials) journal.