A Sustainable Vision of Tomorrow

“Is there anybody in this room who doesn’t have a lithium-ion battery on them?,” began Sir M. Stanley Whittingham in his Lecture at #LINO25 on Tuesday, 1 July. One of three researchers awarded the 2019 Nobel Prize in Chemistry for their contributions to the development of the lithium-ion battery, Whittingham engineered the first functional lithium battery in the 1970s, John B. Goodenough (who passed away in 2023) doubled the battery’s potential in 1980, and Akira Yoshino made the battery practical in 1985. 40 years later, with smartphones, tablets and laptops ubiquitous, the chances of someone in the hall not having a lithium-ion battery on them were extremely slim.

Both Whittingham and Yoshino, in his Lecture held immediately afterwards, offered a potted history of this revolutionary battery. Whittingham’s contribution came about from oil company Exxon wanting to diversify its activities in the early 1970s, and recruiting the best minds in energy research to do so. His remit was broad: “We were to look at anything related to energy, provided it wasn’t oil and gas,” remembered Whittingham. This freedom offered the ideal conditions to explore the energy derived from interactions between various materials.

Soon after, Whittingham developed the world’s first lightweight high energy density rechargeable room-temperature battery: with titanium disulphide as the cathode material and metallic lithium as the anode. “The original batteries we gave away to potential customers as paperweights, with a lithium battery, a solar cell and little watch,” he recalled. “One is on my desk at home, still working, and it’s close to 50 years old now – so, good lithium batteries last forever.”

However, much work still needed to be done to bring lithium batteries to market. Not only were they too weak to power anything of significance, they were unsafe in their original form when scaled up (with the fire brigade eventually getting sick of hearing the call to put out lithium fires).

Goodenough’s contribution was to solve the former problem; almost doubling the battery’s potential by replacing the cathode material titanium disulphide with cobalt oxide. This development was critical for Yoshino to solve the latter problem. He took Goodenough’s cathode, and experimented with a number of new anode materials. Eventually, he struck upon a carbon material, petroleum coke. Using this, his battery contained no pure lithium. Instead, lithium ions could flow back and forth between the electrodes. Not only did this give the battery a long life, but most importantly for widespread commercial application, this also made it safe.

During his Lecture, Yoshino treated the audience to two grainy original videos from 1986 of safety tests on lithium batteries at a cave-like facility. In the first, a lump of iron was dropped on a battery that contained pure lithium, resulting in a dramatic explosion and cries of shock from the scientists present. In the second, the same test was conducted on Yoshino’s lithium-ion battery, and nothing happened. “I believe this was the moment when the lithium-ion battery was born,” he said.

Reaching Full Potential

Although the lithium-ion battery has transformed modern society, neither Whittingham nor Yoshino are resting on their laurels. Whittingham is a major contributor to the Battery500 consortium. Battery500 is a US-based collaboration among national laboratories, academia and industry to create next-generation higher-performing batteries manufactured in a sustainable way and capable of delivering up to 500 Wh/kg. “The lithium-ion battery enabled the electronics revolution; that’s under our belt,” he concluded. “We now have to move on to energy storage on a much larger scale, with batteries that will clean up the environment, make technology sustainable and provide a much more efficient electric grid. If we do this right, it will assist in mitigating global warming.”

Yoshino, meanwhile, is contributing more broadly. He is offering his influence in supporting Japan’s Green Growth Strategy, which aims to achieve carbon neutrality by 2050. This Strategy encourages innovation in 14 promising fields of research linked to decarbonisation of the electric power sector and electrification of other sectors. Yoshino sees his role as encouraging young scientists to pursue research in these areas. “It is my duty as a Nobel laureate to give hope and dreams to younger generations,” he said.

Carbon Capture

As Japan’s Green Growth Strategy shows, better batteries are no panacea, and a future sustainable society will be built on a wide range of green technologies. Following on from Whittingham and Yoshino in the last of three back-to-back Tuesday Lectures, Steven Chu (Nobel Prize in Physics 1997) discussed another one of these technologies – carbon capture – sharing a new method that his laboratory has been working on recently, and most importantly why.

“Let me first remind you that the climate is warming up. If you hadn’t noticed, it’s certainly warm here!” he quipped as the temperature outside was creeping up to 30 °C. “To meet our targets, there’s a growing realisation we’re going to have to capture maybe 10-20 gigatons of carbon per year until we revise our agriculture, until we get the ability to make plastics and concrete and steel and chemicals without carbon emission.” To put this into perspective, Chu said, all the world’s landfill amounts to about 2 gigatons.

How can humanity possibly capture such huge volumes of greenhouse gases? When Chu served as US Secretary of Energy under the Obama administration from 2009 to 2013, he funded a large-scale carbon capture facility called Petra Nova. “The idea was that it would capture a quarter of the carbon dioxide from a pretty large coal plant in Louisiana using amine-based materials to absorb carbon dioxide and pump it underground,” he shared. “But it cost a billion dollars, it used 30% of the energy of the coal plant just to heat up the carbon dioxide to release it, and it was just one quarter of one coal plant.”

With this approach clearly not practical at scale, a number of other methods have been pursued in the interim. However, most of these approaches require a lot of energy to work, roughly 500 kJ/mole of carbon dioxide, Chu said. From the beginning, his group looked at carbon capture with energy requirements in mind. “We thought, naively, that if we had a chemical with an amine on it, the amine would attach to the carbon dioxide,” he recalled. “My postdoc said maybe we can use electrochemistry to just break that chemical bond, and it would be much more efficient because there would be no overhead energy.”

Chu and his team conducted an experiment based on this premise and it worked. However, they later discovered that the process is not reversible – scuppering hopes of it being used for carbon capture. They are currently tweaking their experiment to enable consistent carbon capture. “We think maybe there’s still a chance that this can work,” Chu shared. “We’ll know within three or four days.”

Nearing the end of his Lecture, Chu reflected on the challenges he’s continuing to face in developing carbon capture technology. “I’ve gone into half a dozen different fields, and I stumble in and then get stuff to work,” he said. “Chemistry is a little different: I’m finding out it’s much more complicated!”

But he also shared sage advice from what he has learned so far. “If you grind a little rock and you turn it into bicarbonates, it’s great. But if you have to truck around a gigantic rock, it’s a different story,” he said. “The only thing we know how to move in great quantities are fluids.” Echoing the need for the practical consideration of safety to be addressed before the lithium-ion battery could be rolled out worldwide, practicalities need to be baked into carbon capture solutions from the beginning too, Chu argued. “Things that have nothing to do with physics and chemistry can stop everything – we have to think of these boundary conditions.”