Journal Article X-ray scattering Li-S batteries Li-ion batteries Research Support, U.S. Gov't, Non-P.H.S. TiO2-bronze X-ray absorption spectroscopy atomic pair distribution function cell design electrocatalysis nanocrystalline functional materials nanocrystals nanoparticle assembly nanoparticles negative thermal expansion operando operando studies pair distribution function pair distribution function analysis powder X-ray diffraction sample environments self-assembly small-angle scattering spatial mapping structure–property relationships thin films transition metal nitrides two-dimensional materials variable temperature