Researchers at the Chinese Academy of Sciences have built an all-iron flow battery that completed over 6,000 charge-discharge cycles without measurable capacity loss, a durability milestone published in Advanced Energy Materials. The breakthrough, reported Saturday by OilPrice, arrives as the world's largest battery maker, CATL, separately prepares to mass-produce sodium-ion batteries for heavy-duty trucks. The dual advances signal China's accelerating push to break the global energy storage market's dependence on lithium.
The battery uses iron, one of the most abundant elements on Earth, and a water-based electrolyte that cannot catch fire. That is a direct answer to the thermal runaway risks that have plagued lithium-ion installations from California to South Korea. OilPrice reported that the raw material cost advantage is.
Iron is roughly 80 times cheaper than refined lithium. For utility-scale projects where physical footprint matters less than cost per megawatt-hour stored, that math reshapes the entire economic model. Flow batteries work differently than the solid-state cells in phones and electric vehicles.
Liquid electrolytes sit in external tanks and get pumped through a cell stack. To increase storage capacity, operators simply build larger tanks. That modularity makes the technology uniquely suited for wind and solar farms that need to store energy for four to twelve hours.
It is useless for a smartphone. But the grid does not care about size. The Chinese team, from the Institute of Metal Research under the Chinese Academy of Sciences, tackled a problem that had stumped researchers for years.
All-iron flow batteries suffered from degradation, poor reversibility, and electrolyte crossover. Active materials would migrate through the membrane and gradually destroy performance. The team redesigned the negative electrolyte at the molecular level to stop that migration.
The results, published in the journal Advanced Energy Materials, show over 6,000 cycles with no measurable capacity decay. That equates to roughly 16 years of daily use. No pilot project has been announced yet.
Lab results must now survive real-world conditions—temperature swings, impurities in water, the relentless grind of commercial operation. Here is what they are not telling you. The announcement lands in a specific geopolitical context.
China controls approximately 70% of global lithium refining capacity. It dominates graphite processing, cobalt refining, and battery cathode production. An iron-based alternative does not threaten that dominance—it extends it.
Iron ore is mined in Australia, Brazil, and elsewhere, but China is the world's largest steel producer and already has the industrial infrastructure to process iron at scale. The technology may reduce lithium dependence, but it does not reduce China dependence. Separately, CATL announced plans in April 2025 to mass-produce sodium-ion batteries under a new brand called Naxtra, targeting heavy-duty trucks and passenger cars.
OilPrice noted that Chinese carmakers were the first globally to launch sodium-powered vehicles, though limited range remains a barrier. Sodium is even more abundant than iron. The ocean contains it.
Unlike lithium, no single country or region holds a chokehold on sodium supply. Yadea, a Chinese electric scooter manufacturer, purchased sodium-ion batteries in 2025 for a pilot project using two- and three-wheeled vehicles priced between $400 and $660. The company also deployed battery-swapping stations where riders exchange depleted cells for fresh ones by scanning a QR code.
That model—cheap batteries, frequent swaps, no charging downtime—could work for delivery fleets across Southeast Asia and Africa. The lithium-ion battery's vulnerabilities are well documented. OilPrice cited that roughly one-third of global lithium comes from salt flats in Argentina and Chile, where mining consumes vast quantities of water in arid regions.
Around 70% of cobalt, a critical electrode material, originates in the Democratic Republic of Congo. Amnesty International and other human rights organizations have documented child labor and unsafe working conditions in Congolese cobalt mines for over a decade. Lithium is also finite.
Recycling rates remain low. The International Energy Agency estimated in 2024 that less than 5% of lithium-ion batteries are recycled globally, though that figure is rising as regulation tightens in Europe and North America. Follow the leverage, not the rhetoric.
Every major economy is racing to secure battery supply chains. The US Inflation Reduction Act ties electric vehicle tax credits to domestically sourced or free-trade-agreement-partner minerals. The European Union's Critical Raw Materials Act mandates that by 2030, no more than 65% of any strategic raw material can come from a single third country.
Both laws are aimed squarely at China's lithium processing dominance. Alternative battery chemistries scramble that playing field. If sodium-ion or all-iron flow batteries become commercially viable for grid storage, the strategic value of lithium declines.
The US Geological Survey estimates global lithium reserves at roughly 26 million metric tons. Global iron ore reserves exceed 180 billion metric tons. The difference is four orders of magnitude.
Sodium-ion batteries are heavier and store less energy per kilogram than lithium-ion equivalents. That makes them poorly suited for long-range electric vehicles where weight is the enemy. But for stationary storage, urban delivery vehicles, and short-range scooters, weight matters far less than cost.
CATL's Naxtra brand is betting that commercial fleet operators will choose cheaper batteries with shorter range over expensive batteries with range they do not need. The all-iron flow battery faces its own scaling challenges. The membrane that separates the two electrolyte tanks remains expensive.
Pumping liquid electrolytes requires energy, reducing round-trip efficiency compared to solid-state batteries. And the technology requires a minimum size to be practical—you cannot shrink a flow battery to fit a laptop. The market is grid storage, and grid storage alone.
That market is growing fast. BloombergNEF reported that global energy storage installations hit a record 45 gigawatts in 2024, nearly triple the 2022 figure. The vast majority used lithium-ion chemistry.
If even 10% of that market shifts to alternative chemistries by 2030, it represents a $15 billion annual opportunity. Why It Matters:
The development of commercially viable alternatives to lithium-ion batteries directly affects electricity prices, grid reliability, and the pace of renewable energy adoption. Every solar farm and wind installation requires storage to deliver power when generation drops. Cheaper storage means cheaper electricity.
It also reduces the geopolitical leverage that lithium-rich nations and lithium-processing dominators hold over the global energy transition. A world that can build grid batteries from iron and sodium is a world less vulnerable to supply chain coercion. The key question is whether the lab results translate to factory floors.
The Chinese Academy of Sciences team has not announced a commercialization partner or pilot project timeline. CATL's Naxtra brand is further along, with mass production planned, but no delivery dates or pricing have been disclosed. Yadea's scooter pilot provides real-world data, but the sample size is small and the duty cycle is light compared to grid storage or heavy trucking.
What to watch: CATL's next earnings call for Naxtra production volumes and pricing. Any announcement of a pilot project for the all-iron flow battery. And whether Western battery startups—Form Energy in the US, Altris in Sweden, Faradion in the UK—accelerate their own sodium-ion or iron-air timelines in response to China's moves.
Key Takeaways: - Chinese Academy of Sciences researchers achieved 6,000 cycles with no capacity decay in an all-iron flow battery using a water-based, non-flammable electrolyte. - Iron costs roughly 80 times less than lithium, making the technology economically compelling for utility-scale storage despite lower energy density. - CATL plans to mass-produce sodium-ion batteries for heavy-duty trucks under the Naxtra brand, while Yadea already deployed sodium-ion scooters with battery-swapping stations. - The breakthroughs could reduce global dependence on lithium and cobalt supply chains dominated by a handful of countries, but they extend China's lead in battery manufacturing. The next 18 months will determine whether these technologies cross the chasm from laboratory success to commercial deployment. CATL has the manufacturing scale to move fast.
The iron flow battery needs a partner. The lithium-ion industry is not standing still—prices fell 14% in 2024 alone, according to BloombergNEF. Competition is brutal.
That is good news for anyone who pays an electricity bill.
Key Takeaways
— - Chinese Academy of Sciences achieved 6,000 cycles with zero capacity decay in an all-iron flow battery using non-flammable water-based electrolyte.
— - Iron costs roughly 80 times less than lithium, making the technology economically compelling for utility-scale storage.
— - CATL plans to mass-produce sodium-ion batteries for heavy-duty trucks under the Naxtra brand, while Yadea already deployed sodium-ion scooters.
— - The breakthroughs could reduce lithium and cobalt supply chain dependence but extend China's battery manufacturing dominance.
Source: OilPrice
