Society requires innovative approaches to match the demand for cheap, non-abundant and high capacity energy storage, while also meeting efficient energy conversion demands to best capitalize on renewables or waste products. Through the research new concepts for ceramic interface processing in oxides based electrode/electrolyte arrangements to implicate the Li-transferrence and electrochemical storage capability for solid state batteries based on garnets are reported for whole oxide cell arrangements and performances are discussed. A second significant challenge of solid state battery is to develop strategies avoiding Li-dendrites at ceramic grain boundaries with potential for battery failure in solid state cells; currently Li-garnets are reported to exist in crystalline ceramic phase only. Here this challenge is tackled by the discovery of "polyamorphic" phases in Li-garnet electrolytes which can lead, based on the fundamentals on structure-transport-processing gained, to new design principles of glassy (grain boundary free) solid state battery architectures to avoid Li-dendrites for safe operation. As an extension to the existing application field using Li-garnets as battery electrolytes it is also demonstrated that one may apply those as future electrolyte components in new environmental CO₂ tracker devices for electrochemical potentiometric sensor concepts. Ultimately, research contributes to new material phase discoveries, processing and engienering concepts of efficient solid state battery assemblies based on Li-garnets for safe energy storage and new application fields such as garnet-type potentiometric electrochemical sensors.