Eu-based anolytes for high-voltage and long-lifetime aqueous flow batteries

• 作者: Pan Sun Yahua Liu Peipei Zuo Yuanyuan Li Qianru Chen Zhengjin Yang Tongwen Xu
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（9）
• 页码范围: 368-375
• 页数: 8页
• 语种: 英文

摘要

Aqueous flow batteries(AFBs)are among the most promising electrochemical energy storage solutions for the massive-scale adoption of renewable electricity because of decoupled energy and power,design flexibility,improved safety and low cost.The development of high-voltage AFB is,however,limited by the lack of stable anolytes that have low redox potential.Here we report Eu-based anolytes for high-voltage pH-neutral AFB applications.Eu3+ has a reduction potential of-0.39 V vs.SHE,which can be dramatically lowered when forming stable complex with inexpensive organic chelates.A typical complex,EuDTPA,features a low redox potential of-1.09 V vs.SHE,fast redox kinetics,and a high water solubility of 1.5 M.When paired with ferrocyanide,the battery had an open-circuit voltage of 1.56 V and demon-strated stable cell cycling performance,including a capacity retention rate of 99.997％per cycle over 500 cycles at 40 mA cm-2,a current efficiency of＞99.9％,and an energy efficiency of＞83.3％.A high con-centration anolyte at 1.5 M exhibited a volumetric capacity of 40.2 Ah L-1,which is one of the highest known for pH-neutral AFBs,promising a potent solution for the grid-scale storage of renewable electricity.