Credit: Nature Communications Scientists at Tokyo Institute of Technology (Tokyo Tech), Imperial and High Energy Accelerator Research Organization (KEK) Institute of Materials Structure Science, discover new Ba7Nb4MoO20-based materials with high oxygen-ion (oxide-ion O2-) conductivities--"the hexagonal perovskite-related oxides"--and shed light on the underlying mechanisms responsible for their conductivity. Their findings lead the way to uncovering other similar materials, furthering research on developing low-cost and scalable renewable energy technologies. Over the past few years, fuel cells have become a focal point of research in eco-friendly technology because of their superior abilities to store and produce renewable energy and clean fuel. A typical type of fuel cell gaining ground is the oxide-ion-conducting fuel cell, which is primarily made of materials through which oxide ions (oxygen ions: O2-), can easily move. New materials with higher conductivity at low and intermediate temperatures, provide a number of advantages over commonly used fuel cells based on yttria-stabilized zirconia (YSZ) electrolytes, such as higher power generation efficiency, longer lifetimes, and lower costs.