Scientists discovered a rare planet larger than Jupiter orbiting a distant star once every 180 days. A planet nearly five times as massive as Jupiter circles a distant star once every 180 days. Known as NGTS-38 b, it is an exoplanet, meaning a world that orbits a star outside our solar system. NGTS-38 b is [...]Harnessing renewable resources such as wind and solar energy is vital for the green transition. But these renewables are intermittent and unpredictable. It’s impossible to control when the wind blows and when the sun shines.
Currently, we don’t have to rely on the weather to boil a kettle. That’s largely thanks to our use of fossil fuels. To break our reliance on this finite and polluting source of power, we need to be able to store vast amounts of renewable energy cheaply and safely, but unfortunately, no technologies yet tick all the boxes.
Lithium-ion batteries are used in our phones, laptops, and electric vehicles. But lithium-ion technology depends on costly, geographically concentrated materials such as lithium and cobalt.
Cobalt mining can be a dangerous and polluting process. The organic lithium-ion-containing electrolyte (the liquid chemical between the positive and negative terminals inside a battery) is flammable. Because it poses a fire hazard, it’s risky to deploy these batteries at a large enough scale to power our homes, cities, and industries.
But there is an alternative solution: flow batteries.
In a flow battery, energy is stored in liquid electrolytes which are held in large external tanks. To charge or discharge the liquid, it is pumped through a stack of cells where electrochemical reactions generate or consume electrons. This has several advantages.
Read more: What will batteries of the future be made of? Four scientists discuss the options – podcast
In most batteries, two properties (energy and power) are intrinsically linked. Energy refers to how much electricity is actually stored by the battery and therefore how long that supply can run at a given rate. Power is the rate at which the energy is delivered and how much can be supplied within a given time.
Usually, it’s impossible to change one without changing the other. To store more, you add cells, and that adds power you may not need (and cost you don’t want).
However in flow batteries, this is not the case. Need to store more energy? Simply use larger tanks with more liquid. Need more power? Simply use a bigger cell stack. This ability to independently control power and energy makes the technology cheaper to scale up. Additionally, unlike lithium-ion batteries, flow batteries can’t catch fire (as they are mostly water) and are extremely durable. Some flow batteries have been in operation for more than 20 years.
Several large-scale flow battery systems have already been deployed. In China, the largest systems that connect to the grid reach gigawatt-hour scale (equivalent to powering 100,000 homes for a full day). In Switzerland, what will be the world’s largest flow battery, at 2.1 gigawatt-hours (equivalent to powering over 200,000 homes for a full day) is being constructed to power an AI data centre. Nevertheless, flow batteries are still an emerging technology, with several challenges still to solve.
Worldwide, researchers like us are developing new electrolyte chemistries and materials to reduce the cost of flow battery systems and drive wider adoption. But getting started in flow battery research can be quite daunting. Test cells can often cost thousands of pounds and testing a new cell requires lots of ancillary equipment.
Through our research, we have developed a low-cost 3D-printed test cell. This makes flow battery research much easier and has enabled our research group to test dozens of these cells. But our team struggled to get repeatable test results. It was also difficult to replicate results from previous flow battery studies by other groups in our own labs at Queen’s University Belfast. This resulted in several months of frustration as we scrutinised every aspect of our testing protocols.
As it turned out, our research group was not alone. At a conference in early 2024, we attended a talk by Fikile Brushett, a chemical engineering professor from the Massachusetts Institute of Technology in the US. He described the lack of protocols in this field. Together, we have led a series of studies to investigate and work out how to tackle the issue of reliably replicating data from reported scientific studies.
In one study, published in April 2026, we sent our low-cost 3D-printed test cell to several leading research groups around the world. We were struck by the extent of performance variability between different groups all nominally testing the same battery. Since then, we have identified several potential causes for this variability and have suggested improvements to testing protocols.
Our latest study has involved more than 30 research groups assessing our test cells. Our testing data is now publicly available online. We are using this to pin down why performance varies across the cohort. Our findings will help the community to develop testing protocols that all researchers can use.
Eventually, this work could make it easier for newcomers to make a start in flow battery research. It could also give established groups a reliable foundation to compare results and accelerate their work. This all helps chemical engineers innovate more quickly towards storing renewable energy cheaply, safely and at scale.
Joshua James Bailey receives funding from UKRI's EPSRC.
Hugh O'Connor received funding from UKRI's EPSRC and PSDI.
Society depends on chemistry far more than we consciously realise, from medicines to energy to electronics. However, chemistry is viewed with as much apprehension as gratitude, because of the pollution and health problems that some chemicals cause.
There is a strong desire to have all the benefits of chemistry, but none of the downsides. This has led to terms like “chemical free product” coming into popular usage.
Of course it’s impossible to have a chemical free product – the ingredients in these products are still chemicals. But they employ a different approach, using benign ingredients from nature. These innovative products are examples of “green chemistry”.
Green chemistry takes a holistic – all encompassing – approach to the production of chemicals. This approach brings chemistry into balance with nature and avoids harm. Green chemistry protects the environment and considers the future by design.
Examples of green chemistry include using compounds derived from seaweed to replace man-made plastics. Another is capturing CO₂ from power plants and transforming it into more sustainable fuels for jets and ships. The principles of green chemistry are also being applied to developing smart materials that can change their properties, such as their colour.
Instead of merely making older approaches to chemistry a little bit “less bad”, green chemistry is about finding new functions for the materials we use in our daily lives and getting better levels of performance out of them.
This approach reflects the fact that using resources wastefully can be eliminated through smarter chemistry. This involves rethinking everything, including the supply chains.
An example of finding new functions for existing chemicals includes the use of natural polymers derived from seaweed, called alginates, that are already used in cosmetics and foods, to also replace plastics in packaging so that packaging biodegrades in soil.
The Green Chemistry in America 2026 report published by the Gordon and Betty Moore Foundation surveyed 300 US executives and other leaders from the worlds of research and development and technology. Over 90% of those leaders who were familiar with green chemistry agreed that it delivers a competitive advantage. Some 76% of these leaders said that green chemistry will fuel innovation and long term economic growth.
Countless tonnes of waste are often generated during manufacturing. This can be produced in far greater quantities than the product itself and can turn into pollution. Instead, green chemistry uses waste as a raw material, making chemical use more circular and sustainable.
Instead of changing our climate with gigatonnes of CO₂ emitted from smokestacks, green chemistry is capturing CO₂ and transforming it into products like more sustainable fuels for jets and ships. These synthetic fuels are created by combining green hydrogen (produced from water using renewable electricity) with the captured carbon dioxide.
Near-term investments are advancing the development of dynamic – and sustainable – materials that will change in ways that we want them to on command; such as their colour, or ability to conduct electricity.
These are but a few of the near-term visions of how green chemistry could foster a revolution in innovation. However, these advances need to take place on a timeframe and scale that can benefit humanity in the near future.
Some of the world’s top scientists met in Stockholm in May 2025 to wrestle with the question of how to make this possible. The result was The Stockholm Declaration on Chemistry for the Future.
This declaration contains two particularly important sentences that reflect its purpose. The first of these is that “the chemistry of sustainability recognises that sustainability without innovation is impossible and innovation without sustainability would be ruinous”. The second key sentence is: “While scientific discovery and invention is crucial, it is also not sufficient by itself.”
The Stockholm document goes on to list all the sectors of society that are needed to implement its vision. These include business, investment, education, communication, policy and public support.
All consumers are affected by “bad” chemistry, so they should take decisions accordingly – demanding green chemistry in all products.
The resources available to improve the ways that chemicals are made include sunlight, wind, agricultural and food waste, geothermal energy and – most importantly – human ingenuity. There is an immense potential for innovation.
Paul T Anastas has equity in several carbon dioxide utilisation companies.
Andrew C Marr does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
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