Solid state battery technology has been hailed as the next frontier in terms of energy storage devices because it solves some of the crucial problems with Li-ion batteries, namely, flammability, limited voltage, unstable solid-electrolyte interphase formation, poor cycling performance and strength. In fact, hundreds of millions of dollars are being invested in companies that claim to exploit solid state technology, such as QuantumScape, creating a hype around solid state battery technology (albeit no products have been commercialized). In my talk, I will discuss the microscopic basis for the understanding of ionic motion in solids and show that traditional electrochemical concepts, used for centuries, are not useful for the understanding of ionic motion in crystals. Instead, only a solid state approach, based on quantum mechanical concepts, can be used as a guide for the creation of this new technology. In particular, I will provide a formula for the ionic conductivity of a crystal in terms of its basic microscopic elements that can be used as a guide for the development of super-ionic conductors.