Of greatest benefit to humankind
You may be able to buy them for a couple of quid at your local corner shop, but the humble battery could be key to solving the climate emergency.
They’re hidden inside our everyday gadgets and cost just a few pounds at the local supermarket. Mostly, we only think about them when they run down or pack up. Yet they keep us connected to each other and the wider world and move us around every day. Last year, they won three key creators a Nobel prize. And, by 2050, they might just save the planet.
Welcome to the awesome power of the humble battery. Indeed, when Stanley Whittingham, John Goodenough and Akira Yoshino were jointly awarded the Nobel prize for Chemistry for their work on lithium-ion batteries, the citation was clear. The three had done nothing less than “created the right conditions for a wireless and fossil fuel-free society, and so brought the greatest benefit to humankind”.
The fundamental principle of battery power was demonstrated in 1800 by Alessandro Volta, who proved that the generation of electricity was a chemical process. Every schoolchild still gets to experience Volta’s insight for themselves when they stick a zinc-plated screw into a potato and wire it up to a copper penny – electrons flow from the positive copper cathode, through the potato, to the negative zinc anode, creating an electrochemical cell with enough energy to illuminate a bulb.
But despite their impact, battery technology is based on some fairly well-established principles. “Because the chemistry has been around for more than 200 years, people may think that batteries are not particularly exciting,” laughs Professor Clare Grey, who heads the Todd-Hamied Laboratory, dedicated to developing the next generation of batteries and fuel cells.
In fact, while the Nobel-winning trio’s lithium-ion battery may have ‘created the right conditions’ for remarkable change, it will be up to the current crop of researchers – like Grey and her team, and Manish Chhowalla, Goldsmiths’ Professor of Materials Science – to deliver on the promise of the battery’s potential, exploring innovative battery concepts that have the potential to be as transformative as the original lithium-ion breakthrough.
Batteries are a hot area, because they represent a short-term goal to address the CO2 problem. Can they also be a long-term solution?
In the Grey Group, researchers from more than 20 countries are tackling everything from improving existing battery models – “we’re looking at batteries that roll into the next generation of electric vehicles; we have another set of people who look at materials good for fast charging,” says Grey – to reinventing what batteries are and how they work. “We work on some technologies that are current, and some that are far out,” she says. “And we also do method and theory. We have to come up with not only the understanding of the fundamental processes, but also the blue-sky stuff that will impact on the [net-zero carbon emissions by] 2050 agenda.”
Grey’s own pioneering work has been the application of nuclear magnetic resonance spectroscopy to battery research. “This has a similar working principle to the MRI scanners commonly found in hospitals,” explains Evan Wenbo Zhao, Grey Group postdoctoral research associate. “In order to improve battery performance, we first need to understand how a battery system functions and fails. The tools we’re developing provide this understanding.” Grey likens the technique to ‘a spy’ enabling researchers to see what’s going on inside operational batteries.
Some of the Group’s work engages directly with that of the pioneering Nobelists. Yoshino made Goodenough’s batteries safe by replacing lithium-metal anodes – prone to catching fire – with carbon anodes. However, the resulting battery was less powerful. Now PhD student Anna Gunnarsdóttir is one of a team exploring whether a safe lithium-anode battery might be possible after all: “My work focuses on lithium metal as a potential anode for next-generation ‘beyond Li-ion’ batteries,” she says. “There is now huge interest in lithium metal to make high-energy-density batteries viable.”
The challenges are manifold, from the fundamentals of chemical processes – structural changes arising from each charge of a battery, meaning that some degradation is inevitable – to the realities of market economics. The problem, as Grey explains, is that battery power has to compete with gasoline, which is both a fantastically effective energy source and currently priced in a way that doesn’t reflect its true environmental cost. “Carbon bonds are a very efficient way of storing energy. [Battery developers] have to give people the same amount of energy as they’d get from petrol, but with the same volume, the same mass, and cheaply.”
For Grey, the UK government’s goal (also pledged by 76 other countries at last year’s global Climate Action Summit) of net-zero carbon emissions by 2050, makes “batteries a hot area, because they represent a short-term goal to address the CO2 problem. But can they ever be a long-term solution?”
The Daniell cell, invented in 1836 by John Frederic Daniell consists of a copper pot filled with a copper sulphate solution, into which is immersed an unglazed earthenware container filler with sulfuric acid and a zinc electrode. At some point during the 1860s, this design was improved on by a Monsieur Callaud with the creation of the gravity cell (right). Callaud placed a copper electrode at the bottom of a glass jar and then suspended a zinc anode at the top. He then placed copper sulphate around the electrode and filled the device with distilled water – the result was a battery that would continue to be used in telegraph systems in the US and UK until well into the 1950s.
Manish Chhowalla, Goldsmiths’ Professor of Materials Science and Core Area Champion of the Henry Royce Institute, says that the achievement of net zero by 2050 “will require new materials to enable the energy transition”. He works with materials so new that their existence wasn’t even known until 2004 – so-called 2D materials, crystalline structures comprising just a single layer of atoms. The first one found was graphene, a single layer of graphite that is an immensely powerful electrical conductor, supporting current densities a million times greater than copper. Now 2D materials will help create lithium-ion batteries that can charge mobile electronic devices “in seconds and reduce charging times for electronic vehicles to a few minutes, as well as increasing battery lifetimes to five to 10 years without sacrificing performance,” Chhowalla says.
It would be naive to think that everything we do in the lab today will translate into society in the next five or 10 years. But in 20, or 25? Yes.
The search for new materials with suitable properties, says Grey Group member Dr Supreeth Nagendran, led to another unconventional material, Niobium tungsten oxides, which boast dauntingly complex chemical formulas of Nb16W5O55 and Nb18W16O93. These “exhibit minimal, highly reversible structural changes during discharging and charging, hence can be used at high rates without compromising on safety”, and now have a patent filed and commercial applications in the pipeline.
But each emergent technology must not only be a match for existing energy solutions in efficiency, safety and cost. It must show potential to exceed them. “To bring these new materials in,” explains Chhowalla, “you have to displace the existing technology, which has had investments for 50 years. We can see what the future will look like, based on proof-of-concept devices, but there’s effort to determine whether we can make the materials in large quantities, with the same kind of quality and stability. That’s why it takes a long time for the translation of these advances into real technology.”
In 1859, Gaston Planté created the first rechargeable lead-acid battery; this was swiftly followed by the Leclanché cell of 1866 – a manganese dioxide battery that was to be the forerunner of double-A and triple-A batteries. That essential chemistry still powers batteries today. But progress over the past 50 years has been rapid – spurred by the 1973 oil crisis, in which the price of oil quadrupled. Suddenly, developing fossil fuel-free energy became a priority for those economies most affected – including Britain, the US and Japan. British researcher Stanley Whittingham made the initial breakthrough: an energy-rich material, titanium disulfide, that could house powerful lithium ions in a battery. A few years later, research by American John Goodenough doubled the battery’s power. Finally, the needs of the fast-growing consumer electronics industry then drove Japanese researcher Akira Yoshino to transform lithium-ion battery safety and lifespan – by showing that a simple graphitic carbon could be used as the anode – resulting in the power source we use today. So while fundamental battery principles remain the same, the materials and methods have evolved, and have led ultimately to a game-changing breakthrough – the Nobel-winning lithium-ion battery.
And that’s also why, although innovative technologies offer potentially huge commercial rewards, the breakthroughs may well come from academic and not corporate laboratories.
“The timescale of industry projects is much shorter,” says Grey. “It’d be considered a luxury to do what I do, within industry, yet the techniques we’ve developed are being used across the world.” Chhowalla agrees: “We’re not bound by the strings of the market. We’re able to take on projects with high rewards and a very low chance of success – but the reasons why they fail will give us insights into how to innovate and improve.”
Ultimately, a research environment like Cambridge’s enables scientists “to come up with radically different ways of looking at things, that industry wouldn’t have the remit to do”, says Grey. “We can do it in an unbiased way. We will keep at it for longer.”
“So don’t expect just yet to see a Cambridge-created battery replacing the one inside your phone or car, or scaling up to tasks such as storing surplus from the grid or powering an aeroplane. “It would be naive to think that everything we do in the lab today will translate into society in the next five to 10 years,” says Chhowalla. “But in 20, or 25? Yes.”
“There are technologies that are ready,” says Grey. “But the idea of them being mainstream in less than 15 years is very slim. So we have to make sure we’re doing the fundamental science, and keep coming up with new ideas. Because, ultimately, it’s imperative that we meet the 2050 agenda.”
