Bentalib Abdulaziz, Pan Yanbo, Yao Libo, Peng Zhenmeng
Department of Chemical, Biomolecular and Corrosion Engineering, The University of Akron Akron Ohio 44325 USA
RSC Adv. 2020 Apr 29;10(29):16875-16880. doi: 10.1039/d0ra02010a.
Capacitive deionization (CDI) is an energy saving and environmentally friendly technology for water desalination. However, classical CDI is challenged by a low salt removal capacity. To improve the desalination capacity, electrode materials utilizing the battery mechanism for salt ion removal have emerged as a new direction more recently. In this work, we report a study of amorphous iron phosphate (FePO) as a promising electrode material for pseudocapacitive sodium ion removal. Sodium ions can be effectively, reversibly intercalated and de-intercalated upon its electrochemical reduction and oxidation, with an excellent sodium ion capacity under half-cell testing conditions. By assembling a hybrid CDI (HCDI) system utilizing the FePO electrode for pseudocapacitive sodium ion removal and active carbon electrode for capacitive chloride ion removal, the cell exhibited a high salt removal capacity and good reversibility and durability, which was attributed to the advantageous features of amorphous FePO. The HCDI system achieved a high deionization capacity (82 mg g) in 10 mM NaCl, a fast deionization rate (0.046 mg g s), and good stability and cyclability.
电容去离子化（CDI）是一种用于水脱盐的节能且环保的技术。然而，传统的CDI面临着低盐去除能力的挑战。为了提高脱盐能力，利用电池机制去除盐离子的电极材料最近已成为一个新的发展方向。在这项工作中，我们报道了对非晶态磷酸铁（FePO）作为一种有前景的用于赝电容钠离子去除的电极材料的研究。在其电化学还原和氧化过程中，钠离子能够有效地、可逆地嵌入和脱嵌，在半电池测试条件下具有出色的钠离子容量。通过组装一个混合CDI（HCDI）系统，该系统利用FePO电极进行赝电容钠离子去除，利用活性炭电极进行电容性氯离子去除，该电池表现出高盐去除能力、良好的可逆性和耐久性，这归因于非晶态FePO的有利特性。该HCDI系统在10 mM NaCl中实现了高去离子化容量（82 mg g）、快速去离子化速率（0.046 mg g s）以及良好的稳定性和循环性。
