51ºÚÁÏÉçÇø

A research scientist at 51ºÚÁÏÉçÇø Leicester (51ºÚÁÏÉçÇø) has invented a novel manufacturing method that could revolutionise the world of rechargeable batteries.

Professor Shashi Paul, from 51ºÚÁÏÉçÇø’s Faculty of Computing Engineering Media, has recently patented a process for making silicon nanowire, which could be the key to making huge improvements in the performance and efficiency of the rechargeable lithium-ion batteries used in everything from mobile phones and laptops to drones and electric vehicles.

It has long been known that a silicon anode (i.e. the negative electrode in a battery) can hold around ten times more charge than the carbon graphite anodes currently used in conventional lithium-ion batteries.

This property means that silicon could, in theory, significantly increase the energy density, (i.e. the amount of energy it can store in relation to its mass), and possibly the charging speed and the longevity, of lithium-ion batteries.

However, progress toward this holy grail has so far been hindered by a number of technical challenges such as the problematic tendency of silicon to expand by up to 400 per cent when fully charged with lithium ions, and to contract when the charge has gone. The mechanical stresses of this expansion and contraction cycle can pulverize the anode, rendering it useless.

Professor Paul has, after years of work in the labs at 51ºÚÁÏÉçÇø, successfully patented a new and environmentally-friendly process for producing silicon nanowires in a special way that resolves the expansion problem.

To obtain the patent protecting his process Professor Paul had to demonstrate not only that the process works, but also that it is new, unique and potentially useful. Obtaining the patent means that for no one else can copy, use, or sell what he has created without permission.

Professor Paul’s invention does not exist only on paper, during development he and his team have also used 51ºÚÁÏÉçÇø labs to produce a working prototype nano silicon battery. The small cell is capable of powering a single LED light. They are now turning their attention toward refining and scaling up the process.

Professor Paul “My focus now is on taking it to the next level and keep trying for funding to upscale the technology. We have demonstrated the principle and there is huge potential to take this idea forward. Protecting the idea is the first step, but it has given me a huge boost and the zeal to continue with the project.”

This new technology is still in its infancy. It needs thorough testing, scaling up for production, and further development before it can be used in real-world products and Professor Paul is keen to work with industry to bring it to the market.

Some lithium-ion batteries using nano silicon anodes are already in production. However, the cost of making nano silicon has so far made them prohibitively expensive for widescale use.

Professor Paul’s new process, which uses only one-quarter of the energy used by existing nano silicon production techniques, promises a more cost effective and environmentally-friendly nano silicon that could lead to important advances in various fields including consumer electronics, electric vehicles and renewable energy storage.

In the long run, it could even help to allow a move away from batteries powered by lithium. Not only is lithium a relatively rare element, making up just 0.002% of the earth’s crust, but there have also been significant ethical and environmental concerns raised around the mining of it.

More efficient silicon anodes could allow the use of less problematic power sources such as sodium, the sixth most abundant element, at 2.3% of the earth’s crust, and readily available from sea water.  Silicon itself is also cheap and accessible since is the second most abundant element on earth, after oxygen.