Sodium-ion Batteries and Prussian blue analogues

Abstract

A net-zero society needs integration of a large amount of renewable energy to a power grid while ensuring the quality of electricity. As the intermittent power from the renewables should be load-leveled using low-cost and high-power 1 MWh-scale stationary batteries, sodium-ion batteries that are comprised of abundant elements have attracted recent research interest. One of the most promising positive electrode materials for sodium-ion batteries is a family of Prussian blues (PB) and Prussian blue analogues (PBA), which delivers a large capacity of > 150 mAh/g at a high operating voltage of approximately 3.5 V vs. Na/Na⁺, meeting performance criteria for large-scale stationary batteries. However, for their commercialization, especially in Japan, further data accumulation including cycle stability, safety, and life cycle assessment is necessary. This review summarizes recent research and development of the PB and PBA electrodes for sodium-ion batteries.