Cathode and anode materials for Na-ion battery

Energy storage is more important today than at any time in the human history. The battery systems that are pursued for clean renewable energy-based grid or the electrification of transportation need to meet the requirements of low cost and high efficiency. Li-ion battery is the most advanced battery system, but it is expensive and insufficient as a resource for widespread application. Na-ion battery is seen as a promising alternative due to the abundance of Na resource. However, the realization of the Na-ion intercalation/deintercalation mechanism is also challenging because Na ions are 40% larger in radius than Li ions. This makes the finding of suitable host materials with high storage capacity, rapid ion uptaking rate, and long cycling life not easy. In the recent 3 years, several electrode materials were found to have energy density close to those used in Li-ion batteries. These scientific advances have greatly rekindled worldwide passion for Na-ion battery system. In this chapter, the development of the electrode materials for Na-ion batteries is briefly reviewed, with the aim of providing a wide view of the problems and future research orientations of this system.