The deficiencies of electrochemical energy storage have come to be a major constraint in many areas of technological design. Using a canonical intercalation host, V<sub>2</sub>O<sub>5</sub>, as a model system, I will discuss the structural and electronic origins of diffusion barriers in cathode materials. In particular, I will discuss the coupling of ions with small polarons and the resulting consequences for phase evolution. Scanning transmission X-ray microscopy measurements in conjunction with resonant inelastic X-ray scattering and density functional theory provide a rich picture of the evolution of electronic structure with increasing lithiation. The mitigation of diffusion impediments will be discussed with reference to two distinct approaches: (a) mesoscale structuring given the pronounced size dependence of phase segregation and propagation phenomena and (b) the stabilization of metastable phases that provide frustrated coordination environments and allow for broader energy dispersion of V 3d states. The latter approach has led to the discovery of promising intercalation hosts for Mg- and Ca-ion batteries that exhibit a combination of high voltage, good capacity, and excellent cyclability.

Defining conduction pathways in cathode materials: Resolving ionic logjams through atomistic design and mesoscale structuring

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.