Paul Shearing, University of Oxford

How to achieve net zero and build a circular battery economy is Paul Shearing’s major research priority. The professor of sustainable energy engineering studies the performance of Lithium-ion batteries for a range of applications from consumer electronics to electric vehicles. Now he’s plugging in to dream experiments and AI microscopy to achieve the rare eureka moments required for overcoming Earth’s most urgent challenge.

Shearing was among the first scientists in the world to use an X-ray microscope to look at lithium-ion battery electrodes in three dimensions. Quite rightly, he counts this as a career-defining moment. The professor in sustainable energy engineering at the University of Oxford, UK, started his work 15 years ago. This was back when 3D images of cell phone and electric vehicle batteries were first collected. “We were the first people to use X-ray imaging to understand the detailed, three-dimensional morphology of an electrode,” Shearing says. Electron, optical microscopes, and various types of diffraction and spectroscopy were common back in those days, “but no one really knew for certain what these things looked like in 3D” he says. Now he views never-before seen images regularly that are key to finding materials that can help us to achieve net zero.

The Growing Demand for Lithium Batteries

Governments worldwide have mandated the phasing out of combustion vehicles for electric equivalents. These centralized strategies encouraging the sale and purchase of electric vehicles has led the industry to mature rapidly. In parallel, consumer demand has established Li-ion batteries as a commodity product that many rely on. “We're asking more and more from these energy storage devices” he says. To achieve net zero, Shearing is designing the next generation of batteries, which he hopes will play an even more substantial role in our lives. It’s therefore fundamental that he can zoom in to the individual particles in a battery: where all the fun chemistry happens.

The sudden demand in the early years, however, revealed an issue of range. How could Shearing and his colleagues develop batteries with performance comparable to the combustion vehicles which consumers had become used to? A major issue from the consumer’s perspective is that we’ve since moved from range anxiety to battery life. “Everyone naturally wants their battery to charge more quickly but we also need to ensure this can happen whilst maintaining long life” he says. As societies advance and systems accelerate, consumers expect to charge their battery rapidly rather than overnight and still have the range needed for day-to-day business. This issue sits among many others that the current generation of battery chemistries still pose. “Charging has become a big consumer pull and that puts a lot of stress on the materials inside the batteries” Shearing says. By using microscopy tools, Shearing can understand how the materials respond to different rates of charging and discharging.

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  • Director of the ZERO Institute at the University of Oxford, Prof. Paul Shearing speaks about his experiences with AI enabled X-ray microscopy and how they help him and his team in the mission towards zero-carbon, renewable energy solutions.
Paul Shearing, University of Oxford

Things happen inside batteries. We form interface layers, the particles crack.

Prof. Paul Shearing, University of Oxford

Super resulution raw side view subvolume of a battery, imaged with ZEISS Xradia Versa. Copyright: Paul Shearing

Super resulution raw side view subvolume of a battery

Super resulution raw side view subvolume of a battery, imaged with ZEISS Xradia Versa. Copyright: Paul Shearing
Image Courtesy of Prof. Paul Shearing, University of Oxford

Super resulution raw side view subvolume of a battery, imaged with ZEISS Xradia Versa.

Image Courtesy of Prof. Paul Shearing, University of Oxford

Super resulution raw side view subvolume of a battery, imaged with ZEISS Xradia Versa.

The Key Challenge? – Sustainability

The rate of electric vehicle adoption has increased due to more consumers pledging to reduce their personal emissions to achieve net zero. Whilst this is a step in the right direction, Shearing highlights the need to establish a truly sustainable battery economy. This means understanding the full supply chain: from mining the materials, to manufacturing, to the operation of the vehicles, to the end of an electric vehicle battery’s life. Shearing believes it is “critical to embed sustainability into the entire process.”

He and his colleagues are now looking to some of the Earth’s abundant minerals, such as post-lithium-ion battery chemistries. “Can we use sodium as opposed to lithium?” he asks, to reduce the number of scarcer elements within battery chemistries. For Shearing, the challenges are multiple where he notes price volatility and supply chains as major issues. He considers how we could explore entirely new cell chemistries such as abundant materials like sulphur which is often considered a waste product but can be used in a lithium sulphur battery configuration.

Establishing a Circular Battery Economy

As we move towards net zero goals, batteries will be vital in the shift towards electric mobility and renewable energy. Batteries are in our consumer electronics – but they also facilitate wind farms, solar farms, electric vehicles – and when electric flight eventually takes off, it will place different demands on the battery. To optimize their function and ensure they are sustainable, Shearing says he examines “the intrinsic properties of materials to match those battery applications with the right chemistry.” To make this happen, it’s imperative that Shearing can understand exactly what a material looks like and how it behaves in an operational environment.

For over ten years, he and his colleagues have leveraged microscopy tools to look inside a battery. It allows them to find out what those materials look like during operation, and how they change when cycled hundreds or thousands of times. In a break away from empirical optimization, Shearing says he now has a much more informed view of how to design “exactly the right material for the right battery and how then to translate that to the right application.” But why is this important? He says it shows how a battery should operate in a real-world scenario, allowing him to make an informed decision when designing next generation batteries that are fit for purpose.

X-Ray Microscopy in Battery Development

The advent of X-ray microscopy means that it’s now possible to image a battery without the need to slice and dice it. This non-destructive approach means that the environment of the battery is left intact. It’s also possible to visualize the materials and see how fast a battery charges and how long it lasts before it needs to be recycled. For example, a cell phone battery only lasts for a couple of years which illustrates how fundamental changes at the level of the materials have affected the consumer. With microscopy tools, “You can zoom in and see what's going on inside that black box” Shearing says, though the catch is “the more you zoom in, the smaller the sample gets.”

Shearing’s Dream Experiment

Consider the battery in the back of your mobile phone which is the size of a credit card. Shearing describes how his dream experiment would be to zoom in and observe exactly what an individual particle is doing at any given time. He’d like to charge and discharge the battery: make it hotter and colder and impose other ‘environmental stress’. Then look at it over the course of a year of duty cycle operation to track the individual particle from within the battery to see how it changes. In simple terms: “Things happen inside batteries” he says, “We form interface layers, the particles crack.” Shearing often encounters the unexpected in his experiments: the architecture of the battery itself can change – it buckles or de-laminates. With non-destructive multi-scale X-ray microscopy, he says “we can track how that individual particle is changing in response to a broad range of different environmental conditions, over a long period of time.”

Why is this a dream experiment for Shearing? Without turning to destructive measures, “I can understand everything from a single particle all the way up to a device” he says –“that’s tremendously exciting.”

Paul Shearing, University of Oxford

AI will enable us to more rapidly iterate and optimize the materials, design and deployment process, to achieve the ambitious timescales that are required for net zero.

Prof. Paul Shearing, University of Oxford

A New Frontier for Microscopy with AI

With the first wave of AI-enabled microscopy tools on the market – there is a hope that X-ray microscopy will become much more accessible. Shearing finds this super exciting and says he hopes it will bring a more diverse community of users with various challenges. After years of experience with X-raying batteries and materials, “I have baked in expectations of what an experiment will look like” he says: “it's rare that you get a eureka moment because you know what to expect.” Shearing has developed quite an intuition for battery imaging: “you build up an intrinsic understanding of what to expect” he says. Yet, AI microscopy tools have now changed these assumptions. When imaging materials, it’s now possible to look at much larger objects with much higher resolution than before. AI is completely reframing the possibilities of how much of the sample is visible. It means “we can zoom into the particle that is causing or solving the problem” he says, “which is a new frontier for microscopy.”

The Race to Net Zero

Now with an increasing global consensus about the impacts of climate change, there is an urgency to act quickly. The UK has set ambitious targets to achieve net zero across all sectors by 2050. “For me, net zero is an enormous challenge, but also an enormous opportunity” Shearing says. There are still some carbon intensive industries – such as aviation, freight, chemicals, production, steel production – where it’s unclear which technologies will contribute to their decarbonization. To achieve the ambitious timescales required for net zero, “AI will enable us to rapidly iterate and optimize the materials, design and deployment process” Shearing says. With the deadline to achieve net zero now looming, he warns “we no longer have the luxury of time. We need to do this much more quickly – more efficiently.” Yet Shearing remains optimistic: “we now have sophisticated instrumentation that will help us to fix these problems” he says. AI is changing the way that he and his colleagues look at batteries under the microscope. With this improved understanding, he believes they can build better electric vehicles. These microscopy paradigms may just contribute to net zero in ways that no one could ever anticipate.

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