Batteries play a critical role in modern society. The electrification of transportation and deep decarbonization of the energy infrastructure require the development and deployment of high energy, low-cost battery materials and technologies, but energy storage and electric vehicles have very different requirements and challenges. For energy storage, the challenge is to reduce cost and achieve exceptionally long cycle life (>>10,000 deep charge/discharge cycles) in order to reduce the life cycle cost by three to five times to less than $0.03 kWh^-1. Lithium iron phosphate and redox flow batteries remain the most attractive approaches. Fundamental understanding of the degradation mechanisms over very long cycling is the key to further improve the cycle life of such technologies. Sodium ion batteries are also attractive for energy storage, but the electrode and cell level performances are still behind of what can be achieved with lithium-ion batteries. For electric vehicle applications, lithium metal anodes provide the opportunity for next generation high energy and lost cost batteries. Despite great progresses made in the last few years, controlling system level reaction and failure mechanisms remain a large challenge.