Yu Fei, Yang Yidi, Liu Peng, Ma Jie
College of Oceanography and Ecological Science, Shanghai Ocean University No. 999, Huchenghuan Road Shanghai 201306 P. R. China.
Water Resources and Water Environment Engineering Technology Center, Xinjiang Key Laboratory of Engineering Materials and Structural Safety, School of Civil Engineering, Kashi University Kashi 844000 P. R. China
Chem Sci. 2025 Feb 4;16(11):4635-4645. doi: 10.1039/d4sc08020c. eCollection 2025 Mar 12.
Traditional capacitive deionization (CDI) materials typically exhibit low fluorine adsorption capacity (FAC) due to limitations in the optimization of their specific surface area and chemical composition. A prospective strategy for efficient ion storage is modulating the local electric field strength (LEF) by changing the curvature. In this study, we developed a novel modulator-based curvature modulation method to prepare three different morphologies of NH-MIL-53(Al) electrode materials with similar specific surface areas but different curvatures, which were used to investigate the direct constitutive relationship between curvature and CDI performance. The results show that the urchin-like electrode (NCMOF-3) with high surface curvature has an ultra-high fluoride removal capacity (61.29 mg g ), a fast fluoride removal rate (mg g min), and excellent charging/discharging cycle stability (10 000 cycles). CDI performance exceeds all previously reported MOF electrodes. Finally, in combination with the surface curvature/electric field model, we found that higher surface curvature may lead to higher concentration of ion distribution. The mechanism of action may be that high surface curvature enhances the local electric field enhancement (LEFE) effect of the electrode material, which in turn increases the ion storage capacity and diffusion rate during CDI. This study demonstrates firstly the potential effect of curvature on CDI performance by experimental design. More importantly, this study breaks the limitations of material design based on specific surface area and provides new design ideas for next-generation CDI materials based on curvature structure engineering.
传统的电容去离子（CDI）材料由于其比表面积和化学成分优化方面的限制，通常表现出较低的氟吸附容量（FAC）。一种有效的离子存储策略是通过改变曲率来调节局部电场强度（LEF）。在本研究中，我们开发了一种基于新型调制器的曲率调制方法，以制备具有相似比表面积但不同曲率的三种不同形态的NH-MIL-53(Al)电极材料，用于研究曲率与CDI性能之间的直接本构关系。结果表明，具有高表面曲率的海胆状电极（NCMOF-3）具有超高的氟去除容量（61.29 mg g）、快速的氟去除速率（mg g min）和出色的充放电循环稳定性（10000次循环）。CDI性能超过了所有先前报道的MOF电极。最后，结合表面曲率/电场模型，我们发现较高的表面曲率可能导致更高的离子分布浓度。作用机制可能是高表面曲率增强了电极材料的局部电场增强（LEFE）效应，进而提高了CDI过程中的离子存储容量和扩散速率。本研究首先通过实验设计证明了曲率对CDI性能的潜在影响。更重要的是，本研究突破了基于比表面积的材料设计限制，为基于曲率结构工程的下一代CDI材料提供了新的设计思路。
