Lithium batteries essentially rule our world now. Our phones, cordless tools, and cars, to name a few, all rely on the technology, and it, in turn, relies on our ability to mine and process lithium. And while deposits such as the 2.3 million metric tons of lithium in the Appalachian Mountains suggest that we’ll have a steady supply of the metal for many years to come, it doesn’t change the fact that lithium is relatively expensive, trading at about $26,000 per tonne as of mid-May 2026.

That’s not necessarily exorbitant, admittedly, but there are plenty of cheaper metals out there: Iron ore, for example, trades at just over $110 per tonne. It may have a bright future as a material in more affordable batteries, too: In April 2026, scientists from the Chinese Academy of Sciences’ Institute of Metal Research (IMR) announced that they had developed an “all-iron” flow battery that, according to a research paper published in Advanced Energy Materials, will last 6,000 charge cycles — or about 16 years of daily use — without losing any capacity. For context, the lithium-ion battery in your smartphone will last fewer than 1,000 cycles, while larger batteries may endure up to 5,000 cycles.

Flow batteries differ from conventional lithium-ion batteries in that they submerge the battery elements in an electrolyte fluid. This particular battery uses a new electrolyte that “effectively prevents hydroxide ions from attacking the iron center,” per an IMR press release. This protection for the iron core results in a longer-lasting battery that overcomes the longevity and durability issues associated with previous designs, which tend to degrade very quickly.

Saying that a battery will last for 16 years without losing capacity is all well and good, but can we quantify this durability? Actually, yes. In the same IMR press release, the researchers claim that their iron battery achieved an average coulombic efficiency — the number of electrons transferred <a href="https://jordangazette.com/whats-the-difference-between-american-and-european-traffic-lights/”>between battery electrodes during charging — of 99.4% over more than 6,000 cycles at a current of 80 mA/cm², with no reduction in capacity. It performed impressively at higher currents, too, with 78.5% efficiency at 150 mA/cm². High coulombic efficiency is associated with longer battery life, so this tech looks to have quite a lot of potential indeed.

While this development is certainly promising, we’re unlikely to see all-iron flow batteries in consumer electronics any time soon, if ever. Instead, this tech is intended for long-term grid-scale energy storage, most likely in battery facilities such as California’s massive Darden Clean Energy Project, and will play a big part in the worldwide push toward renewable energy.

Flow batteries, regardless of the tech, look to be the hot new thing in energy storage. Japan and China brought massive flow battery facilities online in April and July 2022, respectively, while U.S.-based startup Ess Tech Inc teamed up with Arizona’s Salt River Project in 2025 to supply flow batteries for Project New Horizon, a 5-megawatt, 50-MWh battery system capable of powering more than 1,000 homes for 10 hours. Time will tell whether the Chinese Academy of Sciences’ battery tech will be deployed on similarly large scales.