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When they get to that speed, electrons generate X-rays and other forms of radiation, which are then used to take measurements and make incredibly detailed images of everything from molecules to motorbikes.
The facility is one of the largest of its kind, with 33 different ‘beamlines’ of various energies and intensities available for researchers in a wide array of fields to use in their experiments. Diamond has been used for experiments on how engine parts wear at the microscopic level, and to explore the long-term effects of laser eye surgery.
The site is celebrating its 15th anniversary this year, and some of the 33 beamlines are helping to tackle one of the biggest energy-related problems facing science and engineering – building better batteries.
The X-rays generated by the synchrotron are capable of determining not only the configuration of substances inside batteries, but also their charge state. “You can do that as the battery is being charged or discharged,” said Laurent Chapon, who has been Diamond’s director of physical sciences since 2016. “If you see the degradation of the battery after a number of cycles you can pinpoint which of the elements is actually causing this disruption in the system.”
The rising cost of lithium – a crucial battery component which has gone from $1,000 to almost $20,000 per tonne – is driving research into sodium batteries. “We are at the forefront of the challenge,” said Chapon. “A lot of the science with sodium batteries has been done on the diffraction beamline.”
He said that sodium research is in its early stages – around where lithium was 20 years ago – but could be crucial to storing solar energy more cheaply in hotter parts of the world. “It’s not the only technique, but what we’re doing is valuable,” he said.
Other research at the facility is focused on squeezing more out of lithium’s potential. On the long-duration experiments beamline, Sarah Day runs weekly tests on samples that range from simulations of Martian seas to wooden pieces of the Tudor warship the Mary Rose.
Day also helps researchers test new forms of lithium batteries – constantly charging and discharging them and seeing how they degrade over the course of months and years. “Putting them through the rigours over time helps see how the structure of the material changes, and understand what dopants can help the capacities stay higher for longer,” she said.
The government recently announced the Faraday Challenge, which includes £246m of funding for research on batteries for electric vehicles, and the Diamond Light Source will play a key role. “One of the key challenges is the degradation of a battery,” said Chapon. “How do defects form, how do dendrites grow and collapse, and how do they essentially wreck your battery?”
At the end of the ‘X-ray imaging and coherence’ beamline, which actually runs beneath the car park under a bump in the road, the University of Manchester’s David Eastwood investigates why lithium batteries fail. “X-rays are a great tool to see inside a battery without disassembling it,” he said.
Using the beamlines, scientists are able to build up 3D models of the internal structure of batteries and diagnose what’s going on inside. They can look for areas where cracks might start to form, or combine their X-ray tomography with thermal footage of the battery charging and discharging to design pressure release valves that stop cells from exploding