High-Performance P2-Type Na0.67Fe0.15Mn0.6Ni0.2Al0.05O2 Cathode Material for Na-Ion Batteries

Abstract

Li-ion batteries are considered to be most promising candidate for grid-scale energy storage in terms of their high energy density and long cycle life; however, their insuffcient lithium resources and high cost of Li might restrict their large-scale application. Based on the abundance and accessibility of Na and its similar electrochemistry to the well-established LIB technology, Na-ion batteries (NIBs) can be the best alternative to lithium-ion batteries. Among various cathode materials, layered oxides have attracted extensive attention owing to their simple structures, high capacities, and ease of synthesis[1]. Herein, we report a new spherical electrode material P2-Na0.67Fe0.15Mn0.6Ni0.2Al0.05O2, successfully prepared by spray drying method. The performance was significantly improved by partial substitution of Ni with electrochemically inactive Al (content of %5). It exhibits a high capacity of 224 mAh g-1 with good capacity retention. This new positive electrode material is potentially utilized for the NIBs made from only earth-abundant elements[2]. [1] Ortiz-Vitoriano, N., Drewett, N. E., Gonzalo, E., & Rojo, T. (2017). High performance manganese-based layered oxide cathodes: overcoming the challenges of sodium ion batteries. Energy & Environmental Science, 10(5), 1051-1074.[2] Yabuuchi, N., Kajiyama, M., Iwatate, J., Nishikawa, H., Hitomi, S., Okuyama, R., ... & Komaba, S. (2012). P2-type Nax [Fe1/2Mn1/2]O2made from earth-abundant elements for rechargeable Na batteries. Nature materials, 11(6), 512-517. Figure 1