Batteries are needed everywhere, for consumer electronics, electric vehicles, and large-scale energy storage on the electrical grid. All of these applications are limited by the capacity, lifetime and safety of current battery technologies. This lecture discusses new chemistries and materials, now being explored in the lab, that could transform the effectiveness of batteries. The new battery materials require nanoscale engineering, and an important part of this work is the ability to observe their performance during battery operation at the scale of atoms and molecules using the X-ray beams at SLAC. These new approaches put us on a path to storing much more energy in a given volume of battery material, thus making batteries smaller, lighter and cheaper, while also increasing their safety and lifespan.