• Chinese scientists developed a water battery capable of surviving 120,000 charging cycles reliably
• Neutral electrolytes prevented corrosion that usually destroys aqueous batteries over time
• The battery reportedly lasts centuries under normal grid storage operating conditions

Scientists from the City University of Hong Kong and Southern University of Science and Technology have developed a new type of water-based battery that could last for hundreds of years without losing its capacity over time.

Published in Nature Communications, the device uses synthesized covalent organic polymers as an anode for magnesium and calcium ions instead of traditional battery materials.

The researchers found a specific compound that combines high-density carbonyl with a rigid honeycomb-like structure that resists corrosion, and this design allows the battery to withstand up to 120,000 charge cycles, which is more than ten times longer than conventional lithium-ion grid storage batteries.

Water batteries are not easy to perfect

Aqueous batteries have always offered safety advantages over lithium-ion because they are nonflammable and have lower upfront costs.

However, they typically store less energy and break down over time due to electrolyte decomposition that corrodes their metal components.

The water-based electrolyte in conventional designs often becomes either extremely acidic or alkaline, which gradually destroys the battery from the inside.

Organic polymers rarely work well in these conditions because they break down quickly when exposed to such harsh chemical environments.

The new design uses a neutral electrolyte with a pH of exactly 7.0, eliminating the extreme conditions that normally cause corrosion.

The specific compound used in the device, called hexaketone tetraaminodibenzo-p-dioxin, maintains a stable flat honeycomb-like structure throughout the battery's entire lifespan.

This structural stability prevents the gradual reduction in capacity that smartphone users know all too well from their aging devices.

The scientists calculated that at current grid storage usage rates of 1.1 cycles per day, their battery could operate for about 300 years before needing any replacement.

More importantly, the electrolytes used in this new design are completely non-toxic and can be safely discarded directly into the environment.

The research team even noted that the electrolyte solution is so harmless that it could be used as tofu brine for home cooking without any health risks.

Commercial hurdles remain

The battery still faces the same fundamental limitation as all aqueous devices, which is lower energy density than lithium-ion systems.

A battery that lasts three centuries but takes up twice as much space may still struggle to find commercial adoption in space-constrained environments.

The manufacturing cost of the specialized organic polymers also remains unclear, and large-scale production could reveal unexpected economic barriers.

Grid storage operators care about cycle life and safety, but they also care about dollars per kilowatt hour delivered over the lifetime of the installation.

A 300-year battery is only useful if the utility company still exists in 300 years, and the economics have to work for the decade ahead, not just the century beyond.

The absence of toxic materials is a genuine breakthrough, but the market will decide whether the trade-offs make sense.

The scientists have most likely solved a chemistry problem, but the commercialization problem is just getting started.

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