X-Ray Nano-Scale Spectroscopic Imaging on Battery Research – A Case Study

Chemical reaction heterogeneity is ubiquitous at both interparticle and intraparticle scales during battery cycling. Spectroscopic imaging provides position-dependent chemical state information that is directly related to the chemical reaction heterogeneity in the samples. Transmission X-ray Microscope has been widely used in battery research as a spectroscopic imaging modality. Simultaneously, it also provides morphological structure information. In this paper, we will present a case study of the characterizations of two types of high-Ni NMC cathode materials that have different primary particle arrangement patterns. They show distinct performances at room temperature. Nonetheless, the thermal stabilities of these two types of materials are inverse compared to their electrochemical performances. The chemical state distributions and morphological structures at the single particle level show consistent evolution behaviors as the observations with neutron diffraction. The results help to reveal the fundamental mechanisms that cause the differences. The case demonstrates the capability of TXM as a spectroscopic imaging tool and its applications in battery research.