Seawater as a potential lithium substitute?
Chloride ions: New hope for green batteries of the future

The search for alternative materials for rechargeable batteries is driving research. Sodium, potassium and zinc were previously considered promising candidates to replace lithium, which is expensive and in limited supply. But now, scientists at Worcester Polytechnic Institute (WPI) have brought an unconventional contender into play: chloride ions from seawater.
Xiaowei Teng, a chemical engineer and professor at WPI, has made a groundbreaking discovery. By incorporating chloride ions, they were able to develop redox chemistry that could potentially lead to the creation of environmentally friendly seawater batteries.
The lithium-ion batteries currently in widespread use have drawbacks. They are costly, rely on scarce raw materials such as cobalt and nickel, and have limited geographic availability. But Teng and his team sought a more sustainable solution. They extended the redox chemistry of iron oxide battery materials by incorporating chloride ions.
Their experiments found that incorporating chloride ions resulted in a crystalline green-rust intermediate that improved battery cycle stability. The team developed a prototype aqueous battery in the lab that is water-based and uses common elements such as iron oxides and hydroxides.
Although the cost has not yet been calculated, the prospects are promising. By using abundant materials such as iron oxides, manufacturing costs could be reduced. Another interesting aspect is the possibility of reusing unused ferrous scrap, thus increasing the sustainability of battery production.
The WPI team's discovery could mark a turning point in battery technology. The combination of sustainability, low-cost materials and improved cycling stability could pave the way for environmentally friendly energy storage. However, further research is still needed to ensure the practicality and efficiency of this new battery technology.
