Operando Detection Of Ion Insertion In Aqueous Battery Using Optical Fiber Sensor

The rapid development and utilization of renewable energy sources such as wind and solar power requires a safe,green,economical and efficient electrochemical energy conversion system that can accommodate/smooth the intermittency of renewable power.Batteries are considered as a promising energy storage scheme due to their advantages of low cost,high energy density and flexible configuration.However,the main challenges facing battery development are safety and performance degradation issues,which in their nature involve the dynamic processes of matter within the battery.In order to solve these problems and promote the development of battery technology,battery analysis technology is very important.Electrochemical technology,as the most basic battery analysis scheme,can evaluate the battery performance through the voltage/current parameters of external circuit,but it gradually fails to meet the needs of deeper exploration of batteries.In recent years,various in situ characterization techniques,such as in situ electron microscopy,Raman,X-ray,plasma imaging,etc.,have made great contributions to the study of the internal mechanism of batteries.However,expensive instruments and complex battery structure design limit the universality of these methods.Fiber optic sensing technology benefits from its characteristics of low cost,high sensitivity and easy integration,which has attracted more and more attention in the field of biology and chemistry.Researchers have considered implanting fiber-optic sensors into batteries,offering a new way to analyze batteries in real-time.Based on the background introduced above,this paper mainly carries out the following work:(1)We proposed an operando battery analysis system using EC-SPR tilted fiber grating sensor.By using the high sensitivity of surface plasma resonance and the stable and small structure characteristics of fiber grating,the ion concentration in the submicron range on the electrode surface of the battery can be monitored with high precision,and then the ion transmission process at the electrode/electrolyte interface can be obtained,providing important internal information parameters for the evaluation of battery performance and analysis of battery’s work mechanism.(2)In situ monitoring of ion insertion kinetic in aqueous zinc ion battery was realized: the ion insertion process was detected by using the above-mentioned optical fiber sensing probe,and the difference between the electron and ion processes was deeply analyzed by combining with the electrochemical information,which provided an in-depth insight into the battery operation mechanism.Finally,the ion intercalation kinetic was qualitatively analyzed.It proves the great potential of optical fiber in situ monitoring technology.The scheme can also be widely used in other systems,which opens a bright window for the development of energy storage system.