China’s water battery hits 120,000+ cycles, can beat lithium by decades

Researchers from the City University of Hong Kong and Southern University of Science and Technology have developed a new water-based, eco-friendly battery based on tofu brine.

“Compared with current aqueous battery systems … our system delivers exceptional long-term cycling stability and environmental friendliness under neutral conditions,” the team said in its paper.

The new battery uses what the team calls “organic” electrodes with neutral, non-toxic electrolytes. According to the team, the new tofu-brine-based battery is capable of 120,000+ charge cycles, and is basically saltwater-level safe.

“Such performance highlights the research potential of this work and underscores its promise for practical application,” the team added.

This means it is neither acidic nor flammable. If scalable, this could prove revolutionary, especially in terms of replacing other battery tech like lithium-ion.

Tofu-brine battery is now a thing

This would be a big deal, as lithium-ion batteries are notoriously highly flammable if damaged and can experience thermal runaway. They are also very hazardous to the environment in terms of waste handling, and can degrade over time (typically between 1,000 and 3,000 charge cycles).

While ubiquitous in many small electronics, they are also very popular in electric vehicles (EVs). In terms of the latter, its inherent flammability has led to many EV fires over the years, which is clearly not ideal.

By comparison, water-based batteries (or aqueous batteries) are considerably safer. They are, by their very nature, non-flammable and contain few, if any, toxic materials.

Such batteries are also much easier and safer to dispose of, and can potentially be made using cheaper and less rare materials. However, they have traditionally struggled with lasting decent enough time.

This is because water tends to break down at certain voltages, limiting performance. The new battery with its headline 120K+ cycles, however, is an enormous leap in utility.

For reference, batteries in things like cellphones typically require around 800 cycles before the battery starts to degrade. EV batteries typically last between 1,500 and 3,000 cycles, and a good LFP grid battery lasts between 6,000 and 10,000 cycles.

Can it scale?

At over a hundred thousand cycles, this could mean a single water-based battery could last at least a decade or so. For applications like grid storage (solar farms, wind balancing), that’s extremely valuable.

And it is this kind of application that the new battery is likely aimed at. While it could, theoretically, be used in things like phones, such batteries have lower energy densities and may not be appropriate in the long run.

It is important to note that battery breakthroughs like this seem to happen all the time in academia, but not all “make it” to market. What really matters is if the tech can be scaled, is energy-dense enough to complete, and can prove cheap at an industrial scale.

New battery tech must also be able to perform reliably outside of lab conditions. If these issues can be addressed/met, then this new battery could have some legs. If it can, then this tofu-brine battery could prove invaluable for renewable grid buffering and rural electrification projects.

It could also find a home as something like a data center backup battery system, or for use in military installations, also as a backup.

You can view the study for yourself in the journal Nature Communications.