Researchers at King Abdullah University of Science and Technology (KAUST) have identified a key molecular factor that limits the performance and longevity of aqueous rechargeable batteries.
The team at KAUST’s Center of Excellence for Renewable Energy and Storage Technologies (CREST) has found that the presence of free water in the battery structure causes harmful chemical reactions, which can be significantly reduced with the addition of common salts like zinc sulfate. Their findings, published in Science Advances, suggest a cost-effective and scalable path toward more durable and safer energy storage technologies.
Husam Alshareef, KAUST Professor and Chair of CREST who led the study, said that, “Our findings highlight the importance of water structure in battery chemistry, a key parameter that has been previously overlooked.”
Aqueous batteries are gaining traction globally as a safer and more sustainable alternative to lithium-ion batteries, especially for integrating renewable energy sources such as solar power into the grid. However, their commercial potential has been limited by issues related to short lifespan and degraded performance over time. The new research addresses this challenge by identifying the root cause of the problem at the molecular level.
One of the main challenges with aqueous batteries is degradation at the anode due to parasitic chemical reactions. These reactions are accelerated by free water, water molecules not tightly bound to other molecules, which interact with anode materials and reduce battery efficiency.
The KAUST team demonstrated that zinc sulfate, a cheap and widely available salt, can minimize the amount of free water, thus curbing parasitic reactions and extending the battery’s life by more than tenfold.
KAUST Research Scientist Yunpei Zhu, who conducted much of the experimental work pointe out that the sulfate salts are cheap, widely available and chemically stable, making the solution scientifically and economically viable. The study found that sulfate ions act like a ‘water glue’, restructuring the behavior of water molecules within the battery. This reduces harmful interactions and stabilizes battery chemistry.
Importantly, preliminary data also suggests that the same stabilizing effect of sulfate may extend to other types of metal anodes beyond zinc, opening the door to more universal application across various battery systems. KAUST Professors Omar Mohammed, Osman Bakr, Xixiang Zhang, and Mani Sarathy were also part of the research team.
As Saudi Arabia and other countries accelerate the adoption of clean energy technologies, the improvement of aqueous battery systems could play a significant role in future energy infrastructure. Industry analysts predict that the global market for aqueous batteries could surpass $10 billion by 2030. The research provides a promising step toward more reliable, environmentally friendly energy storage solutions that align with global and regional sustainability goals.
