China developed durable iron battery technology for 16 years

A team of scientists at the Institute of Metals Research of the Chinese Academy of Sciences (CAS) developed all-iron flow battery technology, providing a durable and economical solution for large-scale energy storage. Research results published in the journal Advanced Energy Materials end of April.

Theo Interesting Engineeringiron flow batteries have great potential thanks to the use of cheap, abundant materials and safe water-based electrolytes. However, the path to commercialization is hindered by technical instability at the cathode. In this battery, the active material tends to decay and leak through the diaphragm, causing rapid wear and tear of the battery, leading to reduced lifespan.

To fix it, the team used “resonance design” at the molecular level, creating a specialized iron complex that acts as a dual layer of defense. According to SCMPthe molecule uses a hard, bulky structure to protect the iron core from chemical attack, while the strong negative charge creates a force field that repels leaking particles. The combination of these mechanisms prevents the battery’s active material from disintegrating or escaping through the diaphragm, thereby ensuring long-term stability.

The battery prototype has proven its durability when estimated to be able to undergo 6,000 charge-discharge cycles, equivalent to more than 16 years of daily operation, without reducing capacity. During that period, the battery also produced no toxic by-products or residue, and achieved 99.4% anti-leakage efficiency. Even at high output power, the battery maintains 78.5% energy efficiency.

The main driving force behind research into all-iron flow batteries is the large price difference between the raw materials. Specifically, the price of lithium is 80 times higher than iron. Experts hope that replacing expensive and scarce lithium with cheap and abundant iron will make it easier to store renewable energy, thereby promoting the global energy transition. One of the difficulties when converting is that electricity from wind or solar is inherently unstable and requires an effective storage plan.

The new research comes as the international race to develop iron flow batteries is accelerating and the technology is increasingly seen as a viable alternative to lithium-ion batteries in large-scale grid electricity storage. In the US, some companies such as ESS Tech have deployed iron flow battery systems for technology companies such as Google.