Ren Xiaoyan, Wang Jiawei, Peng Zhangquan, Lu Lehui
State Key Laboratory of Electroanalytical Chemistry , Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Changchun 130022 , China . Email:
Chem Sci. 2017 Oct 23;9(1):231-237. doi: 10.1039/c7sc03191b. eCollection 2018 Jan 7.
The direct monitoring of trace water in real time during electrochemical cycles is of vital importance because water impurities are one of the causes of reduced lifetimes and capacity fading in Li-ion batteries. However, the most common Karl-Fischer titration lacks the ability to perform real-time monitoring of trace water while the battery is operating. Here, we demonstrate the use of nanosized coordination polymers as a sensing platform for the rapid and highly sensitive detection of water molecules, which gives a distinguishable turn-on fluorescence (FL) response toward water with a quantifiable detection range from 0 to 1.2% v/v, offering a novel opportunity to monitor trace water during electrochemical cycles. To demonstrate the practical value of our platform, we designed an measurement system using nanosized coordination polymers as an electrolyte additive. Within the platform, the findings indicate that trace water is indeed generated during the first discharge process, in which the FL intensity shows a linear increase over time along with the gradual formation of water. We believe that this strategy provides new insights into the monitoring of complex electrochemical processes, and it may help to pave the way for the development of new analytical techniques for lithium-ion batteries.
在电化学循环过程中实时直接监测痕量水至关重要，因为水杂质是锂离子电池寿命缩短和容量衰减的原因之一。然而，最常用的卡尔费休滴定法缺乏在电池运行时对痕量水进行实时监测的能力。在此，我们展示了使用纳米尺寸的配位聚合物作为传感平台来快速、高灵敏度地检测水分子，该平台对水给出可区分的开启荧光（FL）响应，定量检测范围为0至1.2% v/v，为在电化学循环过程中监测痕量水提供了新机会。为证明我们平台的实用价值，我们设计了一个使用纳米尺寸配位聚合物作为电解质添加剂的测量系统。在该平台内，研究结果表明在首次放电过程中确实会产生痕量水，其中FL强度随时间呈线性增加，同时水逐渐形成。我们相信这种策略为复杂电化学过程的监测提供了新见解，并且可能有助于为锂离子电池新分析技术的发展铺平道路。
