According to the official website of the Institute of Chemistry, Chinese Academy of Sciences (ICCAS, published August 18, 2026), with support from the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the New Cornerstone Science Foundation, the team of Wan Lijun/Guo Yuguo at the Molecular Nanostructure and Nanotechnology Laboratory has made new progress in low-cost iron-rich layered oxide cathode materials for sodium-ion batteries. Sodium-ion batteries combine resource and cost advantages and are expected to enable large-scale energy storage applications, driving the green energy transition. However, conventional high-energy layered oxide cathode materials rely heavily on expensive transition metals such as nickel, cobalt, and copper, weakening the cost competitiveness of sodium-ion batteries. In contrast, iron-rich layered oxide cathode materials substitute abundant, inexpensive iron for costly transition metals, which can substantially reduce cathode material costs and promote low-cost sodium battery energy storage technology, although the materials still face key scientific and technical challenges including insufficient cycling stability and unclear failure mechanisms.
Using advanced characterization techniques, the team revealed for the first time that the instability of Fe ions in octahedral coordination is the root cause of the electrochemical-mechanical failure of iron-rich layered oxide cathode materials. The team then proposed a multi-element nanoscale co-doping strategy to synergistically stabilize Fe coordination chemistry: introducing Al(III) and Co(III) in the bulk to strengthen Fe-O bond energy and raise the migration energy barrier of Fe ions, thereby stabilizing the octahedral coordination environment of bulk Fe ions; simultaneously introducing Y(III) (which has high bond energy with oxygen) at the interface to enhance interfacial octahedral coordination stability.
This stabilization strategy effectively suppresses crack- and slip-induced mechanical failure. Ah-level pouch sodium-ion cells assembled with the developed cathode material stably cycle for more than 2,000 cycles. The work reveals the failure mechanism of cost-advantageous iron-rich layered oxide cathode materials and innovatively proposes a strategy to stabilize Fe octahedral coordination chemistry, providing new ideas for developing low-cost, long-life, high-energy iron-rich layered oxide cathode materials. The results were recently published in Nature Nanotechnology (Nat. Nanotechnol., 2026, doi:10.1038/s41565-026-02257-3). The first author is Dr. Jin Ruoxi; corresponding authors are Assistant Researcher Guo Yujie, Researcher Wan Lijun, and Researcher Guo Yuguo.
However, it should be noted that this study is an academic achievement: the reported cycling data of over 2,000 cycles come from laboratory Ah-level pouch cell validation; the material remains in the research stage, with no disclosure of mass-production processes, production line plans, downstream customer validation, or commercialization timelines. Moving from laboratory results to large-scale application will still require overcoming industrialization challenges such as engineering scale-up and consistency control.