Temperature-Tunable Operando Nondestructive Detection of Electronic and Geometrical Structures in Battery Electrodes

Real-time monitoring of the structural evolution of battery materials is crucial for understanding their underlying reaction mechanisms, which cannot be satisfied by the typically used post-mortem analysis. While more and more operando techniques were constructed and employed, they are all based on ambient working conditions that are not generally the case for real-world applications. Indeed, batteries work in an environment where self-heat dissipation increases the surrounding temperature, and extreme temperature applications (<-20 °C or >60 °C) are also frequently proposed. Operando characterization techniques under variable temperatures are therefore highly desired for tracking battery reactions under real-working conditions. Here, we develop a methodology to operando monitor the electronic and geometrical structures of battery materials over a wide range of temperatures based on X-ray spectroscopies. It is substantiated with data collected on a model LiNi_0.90Co_0.05Mn_0.05O₂/Si@C pouch cell under operando quick X-ray absorption fine structure spectroscopy, by which we found a temperature-dependent structure evolution behavior that is highly correlated with the electrochemical performance. Our work establishes an exemplary protocol for analyzing battery materials under temperature-variable environments that can be widely used in other related fields.