Tian Dai

• Dai, Tian; Ahmed, Razan M. N.; North, Eira Tiberg; Valldor, Björn Martin & Koposov, Alexey Y. (2026). Exploring Antiperovskite Cathodes for Na‐Ion Batteries. ChemSusChem. ISSN 1864-5631. 19(10). doi: 10.1002/cssc.70723. Fulltekst i vitenarkiv Vis sammendrag

  Recently discovered cathode materials with antiperovskite (AP) structure have shown a promising performance in Li‐ion batteries. However, their applicability in other battery chemistries have not been well explored. In this work, an AP‐based cathode material, Li 2 FeSeO, was systematically studied for application in Na‐ion batteries (NIBs). Delithiated Li 0.8 FeSeO was used as a precursor for preparing an Na‐ion analog. The electrochemical characterization of Na‐based AP cathode revealed a reversible galvanostatic cycling behavior with an initial capacity of 129 mA g −1 and a capacity retention of 57% after 200 cycles when cycled at a current density of 10 mA g −1 . Up to 0.75 Na + can be reversibly inserted into the AP framework. Synchrotron operando and ex situ X‐ray studies revealed a working mechanism based on a dual redox behavior including both Fe and Se, with Se being the main redox actor. The (de)sodiation capacity below expected value is possibly attributed to the formation of a core–shell structure formed due to kinetic limitation of Na + diffusion into bulk structure, thus preventing a full utilization of the available redox activity. These findings establish AP cathodes as viable candidates for NIBs and provide mechanistic insights that can guide their future structural optimization.

• Dai, Tian; Park, Heesoo; Brennhagen, Anders; Andersen, Niels Højmark; Giorgetti, Marco & Valldor, Björn Martin [Vis alle 7 forfattere av denne artikkelen] (2025). Role of Dual-Redox Couples in Antiperovskite Li2FeSeO Cathodes. Chemistry of Materials. ISSN 0897-4756. 37(22), s. 9091–9104. doi: 10.1021/acs.chemmater.5c01341. Fulltekst i vitenarkiv Vis sammendrag

  In recent years, cathode materials for Li-ion batteries with antiperovskite (AP) structure have attracted growing interest due to their high capacity, chemical flexibility, low cost, and relatively simple synthesis. Among AP cathodes, Li2FeSeO has emerged as a promising candidate, demonstrating high capacity and good cycling stability. However, the lack of fundamental knowledge of the operating mechanism of AP cathodes significantly impedes efforts for further improvement. In this work, the redox mechanism and structural evolution of Li2FeSeO cathode material during electrochemical cycling are revealed through a combination of operando and ex situ X-ray diffraction, X-ray absorption spectroscopy, and Raman spectroscopy coupled with density functional theory calculations. Within the voltage range of 1–3 V vs Li/Li+, two stages in the (de)lithiation process during the initial cycle are determined, involving simultaneous redox activity of Se2– and Fe2+ with strong local structural distortion, leading to the formation of Se22– and Fe3+ species in the delithiated state and possible formation of Fe0 in the lithiated state. While the dual-redox activity of Se2– and Fe2+ ions is the key to high capacity, the −O–Fe–O– framework serves as a crucial element for reversibility during cycling. The study highlights the potential for optimizing the structural frameworks of AP cathodes.

• Dai, Tian; Kouoi, Xavier; Reynaud, Marine; Wagemaker, Marnix; Valldor, Björn Martin & Famprikis, Theodosios [Vis alle 7 forfattere av denne artikkelen] (2024). Antiperovskite active materials for metal-ion batteries: Expected advantages, limitations, and perspectives. Energy Storage Materials. ISSN 2405-8297. 68. doi: 10.1016/j.ensm.2024.103363. Fulltekst i vitenarkiv Vis sammendrag

  Metal-ion batteries, particularly lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries, are currently among the most compelling technologies for energy storage. However, the growing demands driven by wide implementation of batteries in multiple applications call for further improvements of energy and power densities. Despite the incredible developments in this field observed over the past decades, the innovation of new active materials for metal-ion batteries has seen only modest progress, with primary focus on the optimization of already existing materials. The recent discovery of cathode materials with antiperovskite structure signals a promising direction for the creation of relatively simple materials geared towards electrochemical energy storage. These materials can be synthesized through relatively simple chemical processes using abundant elements and could offer stable electrochemical performance. Even though the number of reported examples is still limited, the structural flexibility of these materials offers multiple possibilities for tuning the chemical stability, operating voltage and capacity. This perspective provides a summary of the latest advancements in the field of antiperovskite active materials, highlighting both the advantages and the challenges associated with their integration into metal-ion batteries, and suggests possible future research directions towards practical implementation of this promising yet underexplored class of materials.

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