All-Iron Semi-Flow Battery Based on Fe3O4@CNTs 3-Dimensional Negative Electrode. (20th March 2023)

• Record Type: Journal Article
• Authors: Jiang, Fengjing; Zhou, Xinjie; Guo, Dingyu
• Is Part Of: Electrochimica acta. Volume 445(2023)
• Publication Date: 2023-03-20
• Subjects: All-iron flow battery -- Electrochemical energy storage -- Aqueous flow battery -- Semi-flow battery; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2023.142064
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Low-cost large-scale electrochemical energy storage technology is of great significance for the efficient utilization of clean and renewable energy. In this work, a novel all-iron semi-flow battery is designed using a 3-dimensional Fe3 O4 /Carbon nanotubes (CNTs) negative electrode and K4 Fe(CN)6 / K3 Fe(CN)6 aqueous solution as the positive electrolyte. Fe3 O4 is coated onto CNTs through the co-sedimentation method. It is revealed that two steps of redox reactions of Fe3 O4 exist in the charge and discharge processes and hydrogen evolution happens along with the reaction of Fe(OH)2 to Fe. It is proved to be effective to control hydrogen evolution by adjusting the capacity of the positive electrolyte. As a result, the coulombic efficiency and energy efficiency can achieve 99.3% and 73.1% at 10 mA·cm −2, respectively. The specific capacity at 10 and 20 mA·cm −2 reach 397.8 and 260.6 mA h·g −1 with Bi2 S3 as the additive to the negative electrode. Compared with previous works, the specific capacity and coulombic efficiency are notably improved. Moreover, benefiting from the low cost of the active materials (38.9 $·kw h −1 ), the alkaline aqueous all-iron semi-flow battery could be promising as a low-cost battery technology for large-scale energy storage in the future.