Scientists discover salt that makes batteries last 10x longer
New research shows that sulfate ions reduce the amount of free water to increase the lifespan and performance of aqueous batteries
- Date:
- July 27, 2025
- Source:
- King Abdullah University of Science & Technology (KAUST)
- Summary:
- A team at KAUST has revealed that the short lifespan of aqueous batteries is primarily due to "free water" molecules triggering harmful chemical reactions at the anode. By adding affordable sulfate salts like zinc sulfate, they significantly reduced this issue—boosting battery life over tenfold. The sulfate acts as a “water glue,” stabilizing the water structure and halting the energy-wasting reactions. Not only is this solution simple and cost-effective, but early results suggest it may be a universal fix for various types of metal-anode aqueous batteries.
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Scientists at King Abdullah University of Science and Technology (KAUST; Saudi Arabia) have uncovered a critical molecular cause keeping aqueous rechargeable batteries from becoming a safer, economical option for sustainable energy storage. Their findings, published in Science Advances, reveal how water compromises battery life and performance and how the addition of affordable salts - such as zinc sulfate - mitigates this issue, even increasing the battery lifespan by more than ten times.
One of the key determinants to the lifespan of a battery - aqueous or otherwise - is the anode. Chemical reactions at the anode generate and store the battery's energy. However, parasitic chemical reactions degrade the anode, compromising the battery lifespan.
The new study shows how free water contributes to these parasitic reactions and how zinc sulfate reduces the amount of free water in the battery.
"Our findings highlight the importance of water structure in battery chemistry, a key parameter that has been previously overlooked," said KAUST Professor and Chair of the KAUST Center of Excellence for Renewable Energy and Storage Technologies (CREST) Husam Alshareef, the principal investigator leading the study.
Free water describes water molecules that are not strongly bonded with other molecules. This state allows free water to engage with more molecules than otherwise, triggering unwanted reactions that consume energy and compromise the anode.
Sulfate was found to stabilize the bonds of free water, acting as what the KAUST team describes as a "water glue," to change dynamics of the water molecules that reduces the number of parasitic reactions.
While the bulk of experiments by the KAUST researchers were done on batteries using zinc sulfate, early investigation has shown that sulfate has the same effect on other metal anodes, suggesting the inclusion of sulfate salts into the battery design could be a universal solution for lengthening the lifespan of all aqueous batteries.
"Sulfate salts are cheap, widely available and chemically stable, making our solution scientifically and economically viable," said KAUST Research Scientist Yunpei Zhu, who conducted the bulk of the experiments.
Aqueous batteries are gaining significant global attention as a sustainable solution for large-scale energy storage and are projected to exceed a market size of $10 billion by 2030. Unlike lithium batteries, which are often used in electric vehicles, aqueous batteries offer a safer and more sustainable option for integrating renewable energy sources like solar power into electrical grids.
KAUST Professors Omar Mohammed, Omar Bakr, Xixiang Zhang, and Mani Sarathy also contributed to the study.
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Materials provided by King Abdullah University of Science & Technology (KAUST). Note: Content may be edited for style and length.
Journal Reference:
- Yunpei Zhu, Simil Thomas, Tairan Wang, Xianrong Guo, Yizhou Wang, Chen Liu, S. Mani Sarathy, Xixiang Zhang, Osman M. Bakr, Omar F. Mohammed, Husam N. Alshareef. Correlation of metal anode reversibility with solvation chemistry and interfacial electron transfer in aqueous electrolytes. Science Advances, 2025; 11 (30) DOI: 10.1126/sciadv.adx8413
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