At the National Graphene Institute, University of Manchester, researchers are trying to reduce the size and weight of batteries. For this, they are experimenting with graphene, as this will also increase the lifespan of the batteries. However, before they can start building lighter batteries, they need to understand how graphene interacts with the other chemical components within the battery, especially the electrolytes.
The new project has attracted considerable attention and many commercial partners are involved. They include Morgan Advanced Materials, Sharp and Rolls-Royce. All of them are interested in the future applications of graphene. The research project and applications has attracted over 30 companies from around the world.
Among the many experiments that researchers are conducting, one is to analyze the chemical interaction that takes place between graphene and lithium ions. The quest is to find out how quickly electrons move across graphene, the magnitude of capacitance and the amount of electrical energy that a graphene surface can hold.
The project is also focusing on super-capacitors, especially graphene based, as these tend to have high power densities and longer cycles of life compared to batteries, although their energy storage capacities are lower. However, the advantage they have is they can complement batteries and form an integrated storage solution.
For example, electric cars could use a combination of graphene batteries and super-capacitors to lighten up their load. Typically, batteries for electric cars weigh 200kg or as much as three passengers. If the weight of batteries were to be reduced, it would boost the efficiency of the vehicle and increase its driving range. Electric cares typically have a limitation of 100km, and this is a hindrance to their widespread use.
Increasing the distance the cars travel between charge points will definitely improve their popularity. However, it is still not very clear how the batteries will be able to stand up to the rigors and strains of daily driving. Like all other vehicles, electrical cars too are not driven smoothly; as drivers accelerate, the power demand on the batteries peaks. That stresses the battery and may be a potential cause for limiting its lifespan.
For testing the batteries, researchers will be subjecting prototype graphene batteries and super-capacitor combination to real world stresses that will mimic the profiles presented by different driving conditions. They will even test the batteries under driving in extreme conditions. Batteries are notorious underperformers in cold conditions; therefore, weather chamber tests will be rigorous. That will be instrumental in\ bringing out the weaknesses in the combinations.
The best part is that graphene based storage is useful not only in transport, but in the case of renewable energy sources as well. Usually, wind and solar energy are reliable, but there are times when the wind drops or clouds eclipse the sun. High capacity electrical storage will help to store electricity during periods of low generation.
Manchester is going to be home to a system consisting of a converter system and a grid-scale battery. This will be used for testing possibilities for large-scale electrical storage.
