Bottom line: A mixture most people associate with tofu production could soon help make safer, longer-lasting batteries. Researchers from the City University of Hong Kong and Southern University of Science and Technology have built a water-based power cell that runs on tofu brine – the mineral-rich solution left behind after pressing soy curds.
The design replaces the complex, flammable chemistry of lithium-ion batteries with an electrolyte that's as safe as saltwater. In lab tests, the prototype endured more than 120,000 charge cycles, an endurance record that far exceeds today's commercial standards. Typical electric-vehicle batteries degrade after just a few thousand cycles – even long-duration grid systems seldom survive beyond ten thousand.
At the core of the project lies a concept the team calls "organic electrodes," which interact with a neutral, non-toxic liquid medium. By maintaining a stable pH, this electrolyte avoids the electrochemical breakdown that limits most aqueous batteries.
In conventional designs, water decomposes at higher voltages, creating instability that shortens battery life. The tofu-brine solution suppresses that reaction, allowing energy to flow repeatedly without corroding the battery's internal materials.
The result is a cell that is neither flammable nor caustic – a stark contrast to lithium-ion counterparts known for fire hazards when damaged or overheated. Those safety risks have led to well-documented electric-vehicle fires and complex recycling challenges. Because the tofu-brine system uses benign ingredients, it could simplify end-of-life handling and lessen environmental damage from discarded batteries.
The potential applications extend beyond consumer electronics. High-durability, non-flammable cells are particularly attractive for renewable-energy storage, where batteries must operate reliably for years while balancing the output of solar and wind farms. They could also serve as backup systems for data centers or critical installations that require long service lives.
Scaling remains the big test. Many battery breakthroughs demonstrate remarkable stability in laboratory conditions but struggle to achieve the energy density, manufacturability, or cost efficiency needed for commercialization. Whether tofu brine can compete with lithium-ion's mature infrastructure will depend on how researchers refine the chemistry for industrial production.
If those challenges are met, the team's work – published in Nature Communications – may mark the start of a new chapter in aqueous energy storage by transforming a humble food byproduct into a technological asset.