FEATURE
Professor Simone Hochgreb is Homerton Professorial Fellow in Engineering, with a focus on energy, fluid mechanics and turbomachinery. She is currently part of a Cambridge team working to develop a new method of creating a lithium ion battery using flame spray pyrolysis (FSP). If successful, the process could transform the charging capacity of electric vehicles.
MAKING A BATTERY, ALCHEMISTSTYLE Is the storage capacity the key decider for what might work as a battery? You also need to have good conductivity. It’s about getting the electrons to move when you want. We’ve been playing around with different forms of carbon and experimenting with how they behave in action. You might be able to simulate a million atoms, but that is too small to represent a real material, so you have to test it.
How do you approach the testing? What is the overall aim of this project?
In an ideal world we’ll be looking at what kinds of materials are best for good storage, and how they can be produced. Ideally it would be carbon-based, because it’s readily available and generally not toxic.
If you find a material that works, do you then have to consider what the environmental implications would be if it was scaled up? That’s a really interesting question. For example, one of the materials used in batteries is cobalt. Most cobalt comes from the Congo – what political situation do you create by becoming dependent on it? The technical problems are solvable, and that’s our remit. It’s the political problems which follow that are difficult. But one good thing about metals is that they’re infinitely recyclable, so we wouldn’t be necessarily creating dependence on a finite resource. © iStock.com/peterschreiber.media
There’s a race for higher performance batteries, which means that people with lots of different specialisms are coming together to investigate the possibilities. Material scientists and electrochemists have a number of ideas of what should work, but we do not know what we can produce, so the idea is to combine our expertise.
The current practice is to grind the different materials together in a mortar and pestle, alchemist-style. In this project, we’re looking at how the materials might be produced in a single process, heating some metal precursor droplets to oxidize them into micronsized particles, followed by a process of coating them with carbon.
What is the ideal result that you’re hoping for?
How do you go about exploring what might work? We’re looking at the key storage materials, which often involves a metal and an oxide. They form structures through which the lithium can move in and out, so we can then examine how they behave. For example, nickel, magnesium and cobalt oxides form structures that have good storage capacity.
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