Sun Yiran, Cheng Yujuan, Yu Fei, Ma Jie
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, P. R. China.
College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, P. R. China.
ACS Appl Mater Interfaces. 2021 Nov 17;13(45):53850-53858. doi: 10.1021/acsami.1c15205. Epub 2021 Nov 5.
Designing electrode materials with excellent comprehensive properties was of top priority in promoting development of flow electrode capacitive deionization (FCDI). To date, most FCDI studies involved the application and modification of carbon-based materials, which suffered the contradiction between rheological behavior and electrochemical performance. In this study, a Na superionic conductor (NASICON) sodium vanadium fluorophosphate@reduced graphene oxide (NVOPF@rGO) was synthesized and applied as a flow electrode in FCDI. Benefiting from the confinement effect of the three-dimensional (3D) reduced graphene oxide (rGO) network, thin and uniform NVOPF nanosheets formed and provided abundant active sites for adsorbing Na. Moreover, the interconnected rGO network formed a 3D conductive network for Na and electron transport. Compared with an activated carbon (AC)-AC system (AC was used as an anode and a cathode), a NVOPF@rGO-AC system (NVOPF@rGO was used as a cathode and AC was used as an anode) exhibited preferable dispersibility and stability of electrode dispersion, lower internal resistance, higher desalination rate, and lower energy consumption. Besides, the average salt adsorption rate (ASAR) reached 5.32 μg·cm·min by adjusting the concentration of the electrode (4.73 wt %), the flow rate of the electrode (25 mL·min), and the operation voltage (1.6 V). This study demonstrated the potential of faradic flow electrodes for promoting the development and application of FCDI.
设计具有优异综合性能的电极材料是推动流动电极电容去离子化（FCDI）发展的首要任务。迄今为止，大多数FCDI研究都涉及碳基材料的应用和改性，而这些材料存在流变行为和电化学性能之间的矛盾。在本研究中，合成了一种钠超离子导体（NASICON）钒氟磷酸钠@还原氧化石墨烯（NVOPF@rGO），并将其用作FCDI中的流动电极。受益于三维（3D）还原氧化石墨烯（rGO）网络的限域效应，形成了薄而均匀的NVOPF纳米片，为吸附Na提供了丰富的活性位点。此外，相互连接的rGO网络形成了用于Na和电子传输的3D导电网络。与活性炭（AC）-AC系统（AC用作阳极和阴极）相比，NVOPF@rGO-AC系统（NVOPF@rGO用作阴极，AC用作阳极）表现出更好的电极分散体分散性和稳定性、更低的内阻、更高的脱盐率和更低的能耗。此外，通过调节电极浓度（4.73 wt%）、电极流速（25 mL·min）和操作电压（1.6 V），平均盐吸附率（ASAR）达到了5.32 μg·cm·min。本研究证明了法拉第流动电极在促进FCDI发展和应用方面的潜力。
