Today, most of the demand for portable energy storage is met by lithium-ion batteries (LIBs), which is largely due to their extraordinary performance, including high energy density, operating voltage and long life cycle. However, problems arise in sourcing the needed lithium and cobalt metal, meaning that state of the art LIBs may not be able to fulfill the growing demand for energy storage solutions. Hence, alternative battery concepts and new battery materials are needed which allow for sustainable, safe, compact and high voltage energy storage systems. While it seems unlikely that alternative battery technologies will be able to surpass Li in the area of portable batteries, there is also a growing demand for stationary energy storage and heavy-duty systems. The requirements of those can, on the other hand, be met by a variety of battery types.