Liang Yu, Zhang Hanyu, Huo Mengtian, Zhang Xinye, Qin Kaichi, Wang Huiying, Li Qianyu, Zhao Xingang, Xing Zihao, Chang Jinfa, Zhu Guangshan
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P. R. China.
School of Physics, Northeast Normal University, Changchun, 130024, P. R. China.
Adv Mater. 2025 Feb;37(7):e2415545. doi: 10.1002/adma.202415545. Epub 2024 Dec 23.
Ammonium-ion supercapacitors (AISCs) offer considerable potential for future development owing to their low cost, high safety, environmental sustainability, and efficient electrochemical energy storage capabilities. The rapid and efficient charge-transfer process at the AISC can endow them with high capacitive and cycling stabilities. However, the prolonged intercalation/deintercalation of NH in layered and framework materials often results in the cleavage of the active sites and the deconstruction of the framework, which makes it difficult to achieve long-term stable energy storage while maintaining high capacitance in the electrode materials. Herein, highly redox-active polyoxometalates (POMs) modified [Ag(µ-Hbtc)(µ-Hbtc)] (Ag-BTC) is used as electrode materials. POMs effectively promote the pseudocapacitance storage of NH through a similar interface storage mechanism. At a current density of 1 A g, {PMo}@Ag-BTC exhibited a specific capacitance of 619.4 mAh g and retained 100% of its capacitance after 20,000 charge-discharge cycles. An asymmetrical battery with {PMo}@Ag-BTC and {PW}@Ag-BTC as positive and negative electrode materials, respectively, achieved an energy density of 125.3 Wh kg. The interface-capacitance process enables the full utilization of metal-O (x = b, c, t) sites within the POMs, significantly enhancing charge storage. This study emphasizes the considerable potential of POM-based electrode materials for NH intercalation/deintercalation energy storage.
