Zhu Yueshuai, Zhang Gujia, Xu Chao, Wang Lianzhou
State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350108, P. R. China.
School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia.
ACS Appl Mater Interfaces. 2020 Jul 1;12(26):29706-29716. doi: 10.1021/acsami.0c08509. Epub 2020 Jun 19.
Electrochemical capacitive deionization (CDI) is a promising technology for distributed and energy-efficient water desalination. The development of high-performance capacitive electrodes is critical for enhancing CDI properties and scaling up its applications. Herein, a three-dimensional graphene porous architecture with high CDI performance is successfully constructed by assembling intentionally designed incomplete graphene-based spherical hollow shells. Small graphene oxide (GO) sheets are purposely adopted to prepare sphere shells by wrapping the surface of polystyrene sphere templates. Because the small-sized GO sheets cannot enwrap the spherical templates seamlessly, a unique graphene hollow shell structure with integrally interconnected feature forms upon removal of the templates. Compared to control samples with typical isolated pore structure (3DGA-C) prepared with commonly used large-sized GO sheets, such open and interconnected porous architectures (3DGA-OP) greatly increase their accessibility of specific surface area and pore volume, enabling superior electrochemical performance. The optimized CDI capacities of 3DGA-OP electrodes reach up to 14.4 mg·g in NaCl aqueous of 500 mg·L at 1.2 V, which is about 2 times the 3DGA-C ones (6.7 mg·g) and exceeds the CDI values of most reported pure graphene electrodes under the same experimental conditions. This strategy of improving the open interconnectivity between pores illuminates new avenues for developing high performance CDI porous electrodes assembled from two-dimensional materials.
电化学电容去离子化（CDI）是一种用于分布式和节能海水淡化的很有前景的技术。高性能电容电极的开发对于提高CDI性能及其应用的扩大至关重要。在此，通过组装有意设计的不完全基于石墨烯的球形空心壳，成功构建了具有高CDI性能的三维石墨烯多孔结构。特意采用小尺寸的氧化石墨烯（GO）片通过包裹聚苯乙烯球模板的表面来制备球壳。由于小尺寸的GO片不能无缝包裹球形模板，在去除模板后形成了具有整体相互连接特征的独特石墨烯空心壳结构。与用常用的大尺寸GO片制备的具有典型孤立孔结构的对照样品（3DGA-C）相比，这种开放且相互连接的多孔结构（3DGA-OP）大大增加了其比表面积和孔体积的可及性，从而实现了优异的电化学性能。在1.2 V下，3DGA-OP电极在500 mg·L的NaCl水溶液中的优化CDI容量高达14.4 mg·g，约为3DGA-C电极（6.7 mg·g）的2倍，并且在相同实验条件下超过了大多数报道的纯石墨烯电极的CDI值。这种改善孔之间开放互连性的策略为开发由二维材料组装而成的高性能CDI多孔电极开辟了新途径。
