Polyoxometalate-based sub-1 nm materials: Controllable preparation and energy storage/conversion applications

The sub-1 nm scale is close to the size of the unit cells of many crystalline compounds and the diameter of linear polymers/deoxyribonucleic acid chains. Owing to their dimensions, near 100% surface atomic exposure, and large surface area, SNMs often exhibit unexpected physical and chemical properties (polymer-like behavior, flexibility, rheological behavior, etc.) and excellent optical, electrical, and catalytic properties. For example, the abundant active sites of SNMs result in effective interactions with external fields and outstanding catalytic and energy storage properties. In addition, the sub-1 nm structures can shorten electron and ion diffusion pathways, increase the electrochemically active surface area, accelerate electrolyte penetration, alleviate the stress caused by volume expansion, and improve reaction dynamics. Furthermore, POMs with well-defined structures usually exhibit good redox properties and can simultaneously donate and accept electrons, thus acting as electron sponges in catalytic reactions. Hence, POM-based SNMs combining the advantages of POMs and SNMs hold promise as high-performance energy storage/conversion materials.

This review systematically summarizes the synthesis methods of POM-based SNMs and their applications in energy storage and photothermal conversion. It highlights two key strategies: cluster-nuclei coassembly (CNCA) and the two-phase method. Implemented the precise control of one-dimensional (1D), two-dimensional (2D), three-dimensional (3D) structures, and high-entropy oxide components. These SNMs exhibit nearly 100% atomic exposure, large specific surface areas, and synergistic multi-component effects, demonstrating outstanding performance in energy storage systems such as Li-ion, Na-ion, Li-O₂, Zn-O₂, and Li-S batteries. They effectively enhance battery specific capacity, cycling stability, and reaction kinetics, while also serving as separator to optimize ion diffusion efficiency. In energy conversion applications, their photothermal properties enable efficient solar energy utilization in solar steam generation and seawater desalination. Additionally, the review analyzes current challenges in expanding synthesis methods, scaling up production, investigating formation mechanisms, and practical application of POM-based SNMs. It also outlines future development directions, providing novel insights and critical references for the rational design and development of high-performance energy storage/conversion materials.

This work was supported by the National Natural Science Foundation of China (No. 22305012), the Fundamental Research Funds for the Central Universities and the Xiaomi Young Talents Program, the National Key Research and Development Program of China (No. 2024YFA1211101), the National Natural Science Foundation of China (Nos. 52432004 and U22A20141), and the Research Funding of Hangzhou International Innovation Institute of Beihang University (Nos. 2024KQ102 and 2024KQ131).

About the Authors

Yiting Zhang is currently persuing a master’s degree at Beihang University. Her current research interests focus on the cluster-induced controllable preparation of low-dimensional sub-1 nm materials and their applications in metal-air batteries.

Yu Zhang received his Ph.D. degree in Jilin University in 2007. Then he worked as a fellow in New Energy and Industrial Technology Development Organization, Hiroshima University, Japan. He joined Beihang University in 2013 and now is a full professor of the School of Chemistry. He focuses on advanced energy materials, especially for optimizing electrode structures in Li-O₂ and Li/Na-ion battery field. For more information, please pay attention to his research homepage https://clxy.kmust.edu.cn/info/1027/3725.htm.

Junli Liu received her Ph.D degree in Chemistry from Tsinghua University in 2020. Then she worked as a postdoctor at Tsinghu University from 2020 to 2022. In 2022, she became an associate professor in the School of Chemistry, Beihang University. Her current research focuses on the design and synthesis of cluster-induced low-dimensional sub-1 nm materials and their applications in battery energy storage. For more information, please pay attention to her research homepage https://sce.buaa.edu.cn/info/1024/10993.htm.

About Journal

Polyoxometalates (ISSN 2957-9821) is a peer-reviewed (single-blind), open-access and interdisciplinary journal, sponsored by Tsinghua University. Polyoxometalates publishes original high-quality research papers and significant review articles that focus on cutting-edge advancements in Polyoxometalates, and clusters of metals, metal oxides and chalcogenides. Rapid review to ensure quick publication is a key feature of Polyoxometalates. It is indexed by ESCI, Scopus (CiteScore 2024 = 14.7), Ei Compendex, CAS, and DOAJ. For details about Polyoxometalates, please visit: https://www.sciopen.com/journal/2957-9821.