Scientists at City University Hong Kong created a water‑based battery using magnesium and calcium salts, a solution similar to the brine used in tofu. Unlike lithium‑ion batteries, which rely on flammable solvents and require hazardous disposal, this design is non‑toxic, nonflammable, and environmentally friendly.

“To address the fire risks of lithium batteries, as well as the bulky size and limited power capacity of lead-acid batteries, a research team from City University of Hong Kong (CityUHK) has been awarded funding to develop the next generation of aqueous zinc-based batteries that offer improved safety, higher power, lower cost and environmental sustainability. The team aims to establish a production line with an annual capacity of 1 GWh over three years. This breakthrough addresses large-scale energy storage challenges, providing future data centres with ideal backup power and improving the safe operation of AI facilities in Hong Kong and global markets.” – City UHK Education News

Researchers in China have pioneered a formula for a nontoxic "aqueous battery" that they say could last 10 times longer than today's best devices. What's more, the water battery achieves this epic lifespan without degrading and can be disposed of safely in the environment, the team reported in a new study.

For the new method, researchers used synthesized covalent organic polymers. These tough , organic molecules, such as nitrogen and carbon, are bound together in a tight structure with clear openings and are used as an anode for magnesium and calcium ions.

Organic polymers like this have little use because they are generally short-lived in aqueous batteries; they break down quickly in water-based electrolytes found in this variant of battery, which can be either extremely acidic or extremely alkaline. The electrolyte is essential to moving ions between the anode and the cathode which is why aqueous batteries are a nonflammable and more affordable alternative to traditional batteries.

According to the study, published Feb. 18 in the journal NatureCommunications, the researchers found a specific compound (hexaketone-tetraaminodibenzo-p-dioxin) that combines high-density carbonyl — which is ideal for attracting positive ions — with a rigid tetraaminodibenzo-p-dioxin molecule that keeps the hexaketone in its flat, honeycomb-like structure.

Safety and Efficiency Challenges in Existing Battery Systems

As the world accelerates toward carbon neutrality and renewable energy development, battery technologies have become essential for building a resilient and sustainable energy infrastructure.

Though lithium battery systems currently dominate the market owing to their high energy density, they pose serious safety risks with short-circuiting or overheating concerns. In contrast, approximately 90% of batteries in Uninterruptible Power supply (UPS) backup systems are lead-acid batteries, with inherently low power density requiring over-provisioning of battery units to meet instantaneous power demands. This increases costs, complicates maintenance and limits system flexibility.

To address the industry’s urgent need for safe and sustainable energy storage solutions, Professor Zhi Chunyi, formerly of the Department of Materials Science and Engineering at CityUHK, has devoted many years to researching aqueous electrolyte batteries, achieving major breakthroughs in advancing battery safety and performance. In 2020, he co-founded “Amazinc Energy Limited” with Dr Tang Zijie from his research team, focusing on aqueous zinc-based batteries as its core product.

A Water-Based, Safe and Environmentally Friendly Innovation

Aqueous zinc-based batteries use zinc metal as the main electrode material and water as the electrolyte, eliminating the fire and explosion risks associated with lithium-ion batteries. In addition, zinc is abundant, recyclable and non-toxic, making the entire manufacturing and recycling process more environmentally friendly and cost effective than lithium-based technologies.

To further improve performance and application value, the team will

• Optimize the structure and surface treatment of zinc anode materials to prevent zinc dendrite formation and extend battery life
• Apply a stable protective layer on the cathode’s surface to enhance its dissolution resistance and cycling stability

• Design a two-layer composite separator to further improve battery safety and performance

Building on these material-level improvements, the team will also refine the “cell development process” by precisely controlling key manufacturing techniques, including slurry coating, roll pressing, electrode cutting, tab welding, electrode winding and vacuum electrolyte filling, to further enhance battery consistency, mechanical strength, energy density and cycle life.

In addition, three novel systems, including a battery management system (BMS), a power control system (PCS) and an efficient thermal management system will be developed specifically for zinc-based batteries. These systems will monitor battery status in real time to ensure stable operation, prevent overheating and enhance overall system reliability.

Boosting Industrialization and Production

To accelerate the commercialization, start-up Amazing Energy Limited, the spin-out of City UHK’s flagship innovation and entrepreneurship program will accelerate commercialization. The project is led by Professor Zhang Qichun from the Department of Materials Science and Engineering.

“Our goal is to develop a new generation of battery technology that is both safe and efficient,” said Dr. Tang. “The aqueous zinc-based battery system eliminates fire risks, reduces costs, and can operate safely and reliably in large scale energy storage and back-up power applications. We aim to provide more reliable solutions for data centers, financial institutions, medical systems and high -end commercial facilities.”

Related: Read the full research paper here