First Graphene Ltd (ASX:FGR, OTCQB:FGPHF) is set to introduce its battery anode solution to the UK market.
The company has secured a patent with the United Kingdom Intellectual Property Office for its Hydrodynamic Cavitation technology, which is a process for coating silicon anode particles with graphene platelets to prolong the life of energy storage devices.
The simplified, sustainable process enables the use of silicon in battery anodes. Silicon anodes have the potential to increase energy density levels up to ten times those of conventional graphite anodes.
A battery conundrum
One of the challenges for the green battery industry is how to increase energy storage capacity and silicon may hold the answer.
Traditional carbon anodes typically have an energy density of about 400mAhg-1, whereas the company claims the equivalent potential value for silicon is an order of magnitude higher, at 4200 mAhg-1.
Until now, there have been several barriers associated with using silicon particles, including their low intrinsic electrical conductivity and the slow diffusion rate of lithium within the electrode.
Another major issue is the significant volume change as lithium ions, which are used to transfer electrical charge, enter and leave the electrode, causing the degradation of the silicon electrode. This in turn causes an irreversible loss in performance of the battery.
The problem is maintaining the capacity of the battery after a given number of cycles – ideally greater than 90% after 200 or more cycles – and the solution may be coating silicon particles with a conductive layer that is porous to lithium ions while also mitigating against structural degradation.
Green solution
Graphene, a thin conductive, mechanically strong material, may offer the solution.
The UK patent covers the use of First Graphene’s technology to grow conductive graphene nanoplatelets on the surface of suitable particles, including silicon.
Compared to the current industry practice, which requires temperatures in excess of 900°C, it is a clean solution – useful hydrogen gas is a byproduct.
The company is working on further research to optimise improvement levels, but if the process is commercialised, it promises to be simple and scalable, using readily available feedstocks processed under bulk ambient conditions.
The patent strengthens First Graphene’s intellectual property portfolio in the expanding battery materials market.