(Invited) Intercalation Chemistry in Ordered and Disordered Battery Materials

Abstract

Innovation through structural design has been an effective mean for the realization of today’s batteries. Our ability to master the atomic scale through the identification of host structures and chemistries able to intercalate lithium ions at convenient voltages has been rewarded by the deployment of Li-ion technology and the ushering in of the portable electronics era. A massive effort is now devoted to the improvement of the selected group of materials that have reached commercialization and the development of new materials and chemistries. However, the development of the next generation of energy storage materials requires an unprecedented ability to understand and control all levels of organization of matter and its coupling with function, including disorder and defects, which have often been dismissed as deleterious to performance. However, if understood and controlled, can provide a depth of control and utility to design better materials.Progress in the characterization of disorder is providing unprecedented insights into defect structures. In particular, recent models and tools applied to X-ray scattering techniques, often in complement with electron microscopy or solid-state Nuclear Magnetic Resonance, offer an accessible window for the observation and accurate parametrization of complex microstructural features. Through different examples related to energy storage materials, several of these models will be shown. These comprise those included in X-ray Rietveld refinement programs to extract structural descriptors related to point defects, anti-sites or anti-phase domains; as well as the FAULTS program,which allows to quantitatively describe planar disorder such as stacking faults. The ability to characterize the dynamic evolution of such phenomena using operando techniques will also be discussed.