Linköping University Develops Environmentally Friendly and Cheap Battery for Low-Income Countries

A battery made of zinc and lignin that can be used over 8000 times. Researchers at Linköping University have developed it with the vision that the cheap and durable battery should be able to be used in countries where the availability of electricity is limited. The study is published in the journal Energy & Environmental Materials.

"Solar cells have become relatively cheap and many people in low-income countries have them. But at the equator the sun sets at six o`clock and then the electricity runs out. So even if our battery technology has a slightly lower performance than expensive lithium-ion batteries, we hope that in the long run it will be able to offer a solution for those households and companies," says Reverant Crispin, professor of organic electronics at Linköping University.

Together with his research group at the Laboratory for Organic Electronics and researchers at Karlstad University and Chalmers, he has developed an efficient battery based on zinc and lignin – two cheap and environmentally sustainable substances.

The battery has an energy density equivalent to lead batteries but without the toxic lead. It is stable and can be used over 8000 times but still maintain its performance at about 80 percent. In addition, the battery can hold its charge for about a week, which is significantly longer than other similar zinc-based batteries that discharge in just a few hours.

Batteries based on zinc are already on the market today, mainly as disposable batteries. But they are predicted to complement and in some cases replace lithium-ion batteries in the long run.

"Lithium-ion batteries are good when handled correctly. But they can be explosive, they are difficult to recycle and part of the extraction of certain substances such as cobalt is very problematic from both an environmental and human rights point of view. Then our battery is a sustainable alternative when energy density is not crucial," says Ziyauddin Khan, researcher at the Laboratory of Organic Electronics at LiU.

The problems with zinc batteries have been poor durability as zinc reacts with the water in the battery`s electrolyte solution. The reaction leads to the development of hydrogen gas and the zinc taking on a different structure, something that makes the battery basically unusable.

To stabilize the zinc, an electrolyte with potassium acrylic-based salt (WiPSE) is used. What the Linköping researchers have now been able to show is that when WiPSE is used in a battery with zinc and lignin, the stability is very high. "Both zinc and lignin are super cheap and the battery is easily recyclable. And if you count the cost per use cycle, it becomes an extremely cheap battery compared to lithium-ion or lead-acid batteries," says Ziyauddin Khan.

Currently, the batteries developed in the lab are small. But the researchers believe that they can make large batteries, much like a car battery, thanks to the fact that both lignin and zinc are cheap and available in large quantities. But mass production requires a company to take over.

Reverend Crispin believes that Sweden`s position as a country rich in innovation makes it possible to help other countries to more sustainable alternatives.

"You can see it as our obligation to help low-income countries not to repeat the same mistakes as us. When building their infrastructure, they need to start with green technology right away. If unsustainable technology is introduced, it will be used by many billions of people which will lead to a catastrophe for the climate," says Reverend Crispin.

The research was mainly funded by the Knut and Alice Wallenberg Foundation through the Wallenberg Wood Science Centre, the Swedish Research Council, Åforsk, the Swedish government`s strategic research area on advanced functional materials, AFM, at Linköping University and Vinnova through Fun-Mat II. The long-term collaboration with Ligna Energy AB within the Swedish Electricity Storage and Balancing Center is financed by the Swedish Energy Agency.

Article: Water-in-Polymer Salt Electrolyte for Long-Life Rechargeable Aqueous Zinc-Lignin Battery, Divyaratan Kumar, Leandro R. Franco, Nicole Abdou, Rui Shu, Anna Martinelli, C. Moyses Araujo, Johannes Gladisch, Viktor Gueskine, Reverant Crispin & Ziyauddin Khan; Energy & Environmental Materials 2024 , published online 7 May 2024. DOI: 10.1002/eem2.12752