Exclusive Interview with Zhongke Rongyi He Mingxing: Targeting the Long-Duration Energy Storage Sector, Iron-Based All-Solid-State Batteries Move Toward Pilot Production

Recently, the 2026 World Top Scientists Forum was held at the Lingang Center in Shanghai, with cutting-edge long-duration energy storage technologies becoming one of the key topics of discussion at the event. Zhongke Rongyi showcased its independently developed iron-based all-solid-state energy storage technology at the forum. Taking this opportunity, journalists conducted an exclusive interview with Mr. He Mingxing, Chairman of Zhongke Rongyi.

While the energy storage industry remains fiercely competing on the lithium battery main track, with the industry chain continuously intensifying competition around power density, cycle life, and cost per kilowatt-hour, this company, established less than two years ago, has chosen a more capital-intensive and longer-term technology path: using iron as the active material and adopting an all-solid-state configuration, targeting the 4- to 100-hour long-duration energy storage market.

Long-duration energy storage is becoming a necessity for new energy consumption and grid load balancing, with multiple technical routes being explored in parallel, yet no industry-wide consensus has been reached. Under this context, Mr. He Mingxing, chairman of Zhongke Rongyi, systematically reviewed the iron-based route with the journalist: the technology origin can be traced back to a national strategic proposition in 2011, with 15 years of foundational research accumulated, and is now officially advancing into mid-scale pilot stage. He also shared his judgment on the underlying competitive logic, application boundaries, and industrialization timeline of the long-duration energy storage sector.

“Long-duration energy storage competes primarily on low cost,” Mr. He said. “For the next 3-5 years, cost remains the main driver; safety will gradually become more important; by 5-10 years, both cost and safety will jointly drive development.” Under this framework, Zhongke Rongyi’s iron-based all-solid-state battery is positioned as a viable option for high-safety, high-demand scenarios such as long-duration large-scale storage, nuclear power backup, and data centers, complementing lithium-ion batteries in application scope.

Zhongke Rongyi’s technical foundation is not a recent trend following the booming energy storage sector. Mr. He explained that this route originated from the “Nuclear Energy Storage Battery” research project under China Academy of Sciences’ Strategic Priority Research Program (Class A) “Future Advanced Nuclear Fission Energy — Thorium-Based Molten Salt Reactor Nuclear Power System” in 2011. During the iterative development of fourth-generation nuclear fission technologies, the project required a battery compatible with nuclear power scenarios for load balancing, with two rigid criteria established at the outset: absolute safety and resource self-sufficiency.

“Resource self-sufficiency requires abundant materials, which ultimately led this technology to choose iron as the direction, and thus achieved a significant cost advantage,” Mr. He said. In other words, iron is not a passive substitute for lithium-ion batteries under resource constraints and cost volatility pressure; rather, it was selected from first principles for the special nuclear energy storage scenario demanding extreme safety and resource self-sufficiency.

The resource endowment comparison between iron and lithium is highly persuasive. Mr. He calculated a resource account: for a 100 TWh energy storage scale — an industry expectation to reach this level by around 2040 — if entirely based on lithium-ion technology, the required lithium carbonate would be approximately 60 million tons, nearly equal to the global lithium carbonate production over 30 years. Under the same storage scale, iron consumption only accounts for 0.5% of its annual production capacity. “One is equivalent to 30 years, the other barely 0.5% annually — the gap is enormous,” he said. Chemically, iron atoms can achieve three-electron transfer, theoretically possessing high electrochemical potential to support high energy density. With both abundant resource endowment and favorable electrochemical properties, iron naturally suits large-scale long-duration energy storage; however, constrained by complex engineering bottlenecks, this route has remained in the laboratory stage for a long time, failing to achieve industrialization.

Therefore, Mr. He maintains a relatively restrained view of the iron-based route’s boundaries: its system weight is relatively large, suitable only for stationary energy storage scenarios, not adaptable to vehicular or other mobile applications; it relies on iron’s reversible oxidation-reduction reaction to convert electrical and chemical energy. Affected by electrode reaction kinetics and ion transport, the battery is more suitable for low-rate, long-duration charge/discharge operation, possessing technical characteristics and application potential for long-duration, large-capacity source-side and grid-side energy storage.

“Its limitations lie in two points: first, it cannot be used for mobile vehicular applications; second, it is suitable for large-capacity, long-duration, low-rate energy storage needs, not short-duration, high-power output applications,” Mr. He said. In his view, this is not a “universal battery” route, nor intended to replace lithium-ion batteries, but rather aiming to find structural opportunities in the long-duration energy storage sector, complementing lithium-ion batteries in application scenarios.

It should be noted that iron-air batteries are not a new technology concept; the industry has experienced two major setbacks in its development history. The Edison nickel-iron battery, invented in 1901, eventually faded from mainstream use amid the rise of internal combustion engines; in the 1960s, NASA initiated related technical explorations, and in the 1970s, during the oil crisis, companies such as Westinghouse continued research into automotive applications, but fundamental issues inherent to aqueous systems — including hydrogen evolution, self-discharge, electrolyte dehydration, electrode corrosion, and air cathode efficiency decay — remained unsolved, leading to a near-complete halt in related research around 1984.

He Mingxing’s assessment aligns with this: early iron-air research misaligned its application context, focusing for a long time on heavy-duty vehicles and other mobile platforms. “But iron is not suitable for mobile vehicle batteries, so the initial 10 to 20 years of direction simply failed to move forward.” The success or failure of a technical route hinges on the correct selection of application context; a mismatched scenario, even if the material principles are viable, makes commercialization extremely difficult.

Iron-air batteries previously faced industrialization barriers centered on the side reactions triggered by water in aqueous systems — including passivation, corrosion, hydrogen evolution, and other side reactions. Zhongke Rongyi’s solution is an 800°C high-temperature all-solid-state technology route.

He Mingxing explains that traditional aqueous iron-air batteries primarily rely on hydroxide ions in alkaline electrolytes for conduction; the presence of water makes the iron electrode prone to hydrogen evolution and other side reactions; simultaneously, carbon dioxide in the air reacts with the alkaline electrolyte to form carbonate, degrading electrolyte performance. Although these issues can be mitigated through material modification and system design, they remain long-standing challenges for aqueous systems. Zhongke Rongyi’s system, however, relies solely on the iron oxidation-reduction cycle, with no free water or flowing gaseous or liquid media inside the system — thus avoiding the hydrogen evolution side reactions and alkaline electrolyte carbonateation issues inherent to aqueous batteries.

The all-solid-state architecture inevitably confronts industry-wide common challenges — solid-solid interface impedance. He Mingxing notes that even when two solid materials are pressed tightly under external force, microscopic gaps still exist at the interface, hindering smooth electron and ion conduction.

Mainstream lithium-based solid-state batteries are constrained by the chemical properties of active materials such as lithium and sulfur, and are generally unable to withstand high-temperature environments; most opt for gel or semi-solid routes, relying on introducing a small amount of liquid phase to improve interfacial conduction. Zhongke Rongyi, however, fully leverages the unique advantages of high-temperature systems, employing a multi-layer co-sintering process to sinter each layer of solid matrix into a single unit, “achieving complete solid-solid interface connection.” Here, high temperature is no longer a safety risk but becomes the core solution to overcome interface bottlenecks: high temperature accelerates electrochemical reaction kinetics, while sintering techniques eliminate interfacial gaps.

“Actually, any high temperature is not a problem. The issue is whether there is an active material; without an active material, no problems arise,” He Mingxing says. Iron and ceramic-based matrices inherently exhibit exceptional thermal stability — even at 2000°C, they will not combust or explode. The entire technical solution was originally developed for nuclear power plant applications, with rigorous safety assessments already completed — this is a prerequisite for compatibility with nuclear power plant systems.