Battery and Fuel Cell Materials with Hyperordered Structures

The analysis of real-space functions, such as a reduced pair distribution function, obtained by total scattering measurements has been utilized as a method to reveal the atomic configuration of glasses and liquids. Such analysis has recently been applied to crystals, and is used to uncover structures without translational symmetry hidden in the atomic arrangements of crystals (e.g., locally ordered arrangements of elements occupying the same crystallographic sites or irregular structures around point defects). These structures in crystals are generally referred to as local structures (hyperordered structures), and the difficulty in elucidating them has hindered understanding the relationship between the function and atomic configuration in crystals. However, recent outstanding developments in quantum beam experiments have led to remarkable progress in the study of local structures. Therefore, such analytical methods are expected to be applied to industrial materials utilized in society. This chapter focuses mainly on rechargeable (secondary) batteries, which are key technologies for realizing a sustainable society, and introduces analytical examples of local structures in crystalline rechargeable battery materials. Research on materials used in another electrochemical device (solid oxide fuel cell), is also reviewed, and it is shown how local structure analysis via total scattering measurement contributes to the establishment of material design in the field of energy technology.