The battery that breathes air could be the key to cheaper grid storage

Science · Published 20 October 2026 Swipe more like this →

In short: Most batteries are limited by the materials they carry inside. Zinc–air batteries break this rule by using the oxygen in the atmosphere as a primary reactant. This high energy density makes them a compelling, low-cost alternative for everything from hearing aids to massive utility-scale energy storage.

Zinc–air batteries function by oxidizing zinc particles in a porous anode saturated with an electrolyte. When oxygen from the air reacts at the cathode, it forms hydroxyl ions that migrate into the zinc paste to create zincate. This process releases electrons for power, while the water and hydroxyl are recycled, meaning water is not consumed during discharge. While the theoretical voltage is 1.65 volts, practical cells typically operate between 1.35 and 1.4 V.

The technology offers a unique hybrid between a battery and a fuel cell. Because the reaction rate can be controlled by air flow and the oxidized zinc paste can be replaced, these cells possess high specific energy. They are also notably more abundant than lithium; as of 2020, global zinc reserves were estimated at 1.9 billion tons, compared to just 86 million tons of lithium. This abundance, combined with low production costs, positions zinc–air as a frontrunner for large-scale applications like electric vehicle propulsion and grid storage.

However, the chemistry presents distinct engineering hurdles. Because they require atmospheric oxygen, these batteries cannot be sealed in airtight holders; they require one liter of air for every ampere-hour of capacity used. They are also sensitive to the environment: high temperatures and low humidity cause rapid water loss, while high humidity can flood the cathode with excess water from the deliquescent potassium hydroxide electrolyte. Furthermore, while primary cells are stable, rechargeable versions face challenges like dendrite formation and low cycle efficiency, often requiring mechanical systems to replace depleted zinc and electrolyte.

Despite these complexities, the economic potential is significant. Eos Energy Storage projects that their zinc-based batteries can store electricity at approximately US$160/kWh, which is significantly cheaper than competing technologies that range from $400 to $1,000 per kilowatt-hour. This cost advantage could make them more viable than new natural-gas peaking power stations for stabilizing the electrical grid.

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