Operando photoelectron spectroscopy for the study of Li-ion batteries

Understanding the electrochemical reactions occurring inside a Li-ion battery (LIB) is crucial to further develop this technology and allow for greener and more sustainable energy solutions. In order to do this, there has long been a strive towards developing operando techniques, which allow for probing the battery during operation, and under more realistic conditions compared to post mortem studies (after battery cycling). Operando studies, in theory, allow for studying the reactions of the battery materials as they are happening, and can shed light on the kinetics of the many different reactions occurring at the LIB interfaces. This can in turn give valuable knowledge for how to optimize the battery performance, for example by tuning the interfacial properties. However, performing operando measurements often involve several practical challenges, including designing a suitable cell, developing a working methodology and understanding the effects the method/technique has on the processes one is trying to study. In this regard, performing operando measurements is rarely a straightforward task, and a lot of effort can be necessary in order to setup a working experiment. In this presentation I will highlight and discuss both the possibilities and challenges of performing operando photoelectron spectroscopy studies on LIBs, and in addition give some examples of recent results gained from studies performed at the HIPPIE beamline at MAX IV.