Hong Kong Scientists Use Tofu Brine for Safe New Battery

Scientists searching for a safer alternative to lithium-ion batteries found their answer in an unexpected place: the tofu aisle.

Researchers at City University of Hong Kong developed a new water-based battery that uses magnesium chloride or calcium chloride as its electrolyte. These same mineral salts are the brine used to coagulate soy milk into tofu.

The breakthrough comes at a critical time. China now leads the world in electric vehicle and renewable energy production, flooding society with lithium-ion batteries that power phones, computers, and cars. Within years, the country will face millions of tons of battery waste annually.

Traditional lithium-ion batteries pose serious risks. They use flammable solvents that can catch fire or explode if damaged, creating blazes that water can't extinguish. That's why airlines banned portable batteries and power banks from checked luggage.

Water-based batteries eliminate these dangers entirely because nothing in them can ignite. Despite being developed for over 200 years, they never caught on because the electrolytes were either too acidic or too alkaline, creating their own set of problems.

The Hong Kong team needed something nontoxic, water-based, and pH neutral. Looking to food additives, they discovered the perfect solution in tofu brine.

Why This Inspires

The battery survived 120,000 charge cycles in testing, far outlasting conventional batteries. When it finally wears out, you can dispose of it anywhere without environmental harm.

"Compared with current aqueous battery systems, our system delivers exceptional long-term cycling stability and environmental friendliness," the team wrote in Nature Communications this February. Magnesium and calcium occur naturally in soil, so their presence poses minimal environmental risk.

The research shows how solutions to our biggest technological challenges might already exist in everyday life. Sometimes the future of energy storage isn't about inventing something completely new, but recognizing the potential in what's already safe, abundant, and sitting in our kitchens.

This tofu-inspired battery offers a glimpse of a world where our devices power up without powering down the planet.