(Invited) Insights into the Effects of Doping on Structural Phase Evolution of Sodium Nickel Manganese Oxide Cathodes for High-Energy Sodium Ion Batteries

High-performance and low-cost transition metal (TM) layered oxides using earth abundant elements are promising cathodes for Na-ion batteries. However, it is challenging to obtain desired materials because the large Na size, different Na occupations and various layer stacking sequences multiply the complication in determining the structure of a given composition and exacerbate uncertainty to the structure-property correlation. In this work, we use the attainment of desired Na x Mn y Ni z TM 1−y-z O 2 -based cathode materials as model compound to demonstrate a general roadmap for batch development of sodium layered cathodes towards practical applications. Several cost-effective O3 and P2/O3 hybrid cathode materials have been obtained, all of which demonstrate excellent performance. Acknowledgement: This work is supported by the U.S. Department of Energy (DOE) Office of Electricity under contract No. 57558. PNNL is operated by Battelle Memorial Institute for the DOE under contract DE-AC05-76RL01830