Aviation electrification is arousing a growing interest from the aviation community and beyond. To meet climate challenges, breakthrough aircraft technologies are designed, developed, and experimented. Small recreational aircraft are already being operated in some countries. Powered by clean energy, they have great potential to shape a carbon-free future for aviation. Being hybrid, electric or hydrogen aircrafts, those novel designs rely on battery technologies. New aircraft types also comes with new challenges, some of which are related to batteries. Today, the aviation electrification only touches on small aircraft due to the limited energy capacities of batteries. Significant improvements in battery energy density are critical in opening up the range of possibilities in aviation electrification for commercial aircraft. In addition, from the production of its raw materials to the end-of-life battery disposal, the sustainability of the battery supply chain is key to ensure the environmental integrity of the aviation's transition towards a electrification future.