Eco-friendly battery developed for low-income countries
"Solar panels have become relatively inexpensive, and many people in low-income countries have adopted them. However, near the equator, the sun sets at around 6 PM, leaving households and businesses without electricity. The hope is that this battery technology, even with lower performance than the expensive Li-ion batteries, will eventually offer a solution for these situations," says Reverant Crispin, professor of organic electronics at Linkoping University.
Crispin's research group, along with researchers at Karlstad University and Chalmers, developed the battery using zinc and lignin. It has a comparable energy density to lead-acid batteries but avoids the use of toxic lead.
The battery remains stable through over 8000 cycles, maintaining about 80% of its performance. It can retain its charge for about one week, significantly longer than other zinc-based batteries.
Zinc-based batteries are mainly available as non-rechargeable products. The research indicates they could eventually complement and even replace lithium-ion batteries when rechargeability is effectively integrated.
"While lithium-ion batteries are useful when handled correctly, they can be explosive, challenging to recycle, and problematic in terms of environmental and human rights issues when specific elements like cobalt are extracted. Therefore, our sustainable battery offers a promising alternative where energy density is not critical," says Ziyauddin Khan, a researcher at the Laboratory of Organic Electronics at LiU.
A primary challenge with zinc batteries is their poor durability, due to zinc reacting with the water in the battery's electrolyte solution. This reaction produces hydrogen gas and causes dendritic growth, which renders the battery unusable.
The research team used a potassium polyacrylate based water-in-polymer salt electrolyte (WiPSE) to stabilize the zinc. This substance enhances the stability of the battery when combined with zinc and lignin.
"Both zinc and lignin are super cheap, and the battery is easily recyclable. And if you calculate the cost per usage cycle, it becomes an extremely cheap battery compared to lithium-ion batteries," says Ziyauddin Khan.
Currently, the batteries developed in the lab are small, but the researchers believe they can produce larger versions, similar in size to car batteries, given the abundance of lignin and zinc. However, mass production would require the involvement of a company.
Reverant Crispin emphasizes Sweden's innovative role in promoting sustainable alternatives globally.
"We can view it as our duty to help low-income countries avoid making the same mistakes we did. When they build their infrastructure, they need to start with green technology right away. If unsustainable technology is introduced, it will be used by billions of people, leading to a climate catastrophe," says Reverant Crispin.
Research Report:Water-in-Polymer Salt Electrolyte for Long-Life Rechargeable Aqueous Zinc-Lignin Battery