Scientists have found that the ultra-strong material is capable of storing energy directly, potentially revolutionising the design of future electric -powered vehicles.
If the technology becomes commercially available it could allow manufacturers to ditch heavy batteries and halve the weight of future cars
Commercially available carbon fibre is made with small crystals and has good electrochemical properties – the ability to operate as electrodes in a lithium-ion battery. Although weaker than some varieties, it is still stronger than steel
Leif Asp, a professor of material and computational mechanics at Chalmers University of Technology, looked at how carbon fibres can be used as more than a reinforcing material.
‘A car body would then be not simply a load-bearing element, but also act as a battery,’ he said.
‘It will also be possible to use the carbon fibre for other purposes such as harvesting kinetic energy, for sensors or for conductors of both energy and data.
‘If all these functions were part of a car or aircraft body, this could reduce the weight by up to 50 per cent.’
The researchers looked at how well the structure of different commercially available carbon fibres stored electricity.
Samples that had small crystals in them have good electrochemical properties – the ability to operate as electrodes in a lithium-ion battery – but tend to be not as strong.
According to Professor Asp, this slight loss in stiffness is not a major issue as the weaker carbon fibre with good electrical properties were still stronger than steel.
‘A slight reduction in stiffness is not a problem for many applications such as cars,’ he explained.
‘The market is currently dominated by expensive carbon fibre composites whose stiffness is tailored to aircraft use.
‘There is therefore some potential here for carbon fibre manufacturers to extend their utilisation.’
HOW DOES CHARGING A BATTERY WORK?
In their simplest form, batteries are made of three components: a positive electrode, a negative electrode and an electrolyte.
When a battery is charging, lithium ions are extracted from the positive electrode and move through the crystal structure and electrolyte to the negative electrode, where they are stored.
The faster this process occurs, the faster the battery can be charged.
The material a battery is made of can severely restrict this rate.
Graphite is a commonly used material for the negative electrode as it accepts positive ions well and has a high energy density.
In the search for new electrode materials, researchers normally try to make the particles smaller.
However, it’s difficult to make a practical battery with nanoparticles as it creates a lot of unwanted chemical reactions with the electrolyte, so the battery doesn’t last as long, plus it’s expensive to make.