Point defect-mediated properties in ceramics, particularly ionic conductivity, catalytic activity, and chemical expansivity, govern performance of solid-state electrochemical energy devices. This talk will describe both in-depth systematic studies on model structures and high-throughput screening methods to identify design principles and compositions that can extend the lifetime or efficiency of electrolyzers, fuel cells, and all-solid-state batteries. In one example, we have developed near-zero-chemical-strain electrodes and membranes for enhanced durability by tailoring crystal symmetry and the location of redox (anion vs. cation). In a second example, we have dramatically increased the catalytic activity of fuel cell/electrolyzer electrodes for oxygen surface exchange by orders of magnitude through a new in-situ crystallization route that produces a beneficial defect chemistry for charge transfer and preserves a pristine surface chemistry. Lastly, for Li-ion batteries, we have developed a defect-focused descriptor screening recipe to identify air-stable superionic solid electrolytes with intrinsic Li sublattice disorder and compatibility with high/low voltage electrodes. Advanced processing and high-throughput characterization methods for solid-state ionic materials developed in the course of the work will be highlighted.