A Comparative Study of Layered Transition Metal Oxide Cathodes for Application in Sodium-Ion Battery

Nowadays, efficient, safe, low cost and environmentally friendly storage systems are required in response to the modern society needs. Li-ion batteries (LIBs), considered one of the promising systems to fulfill these requirements, represent the most widespread secondary battery for consumer and portable electronics and possibly for power hybrid and electric vehicles.[1]  Stationary energy storage, in contrast to high energy density applications, is principally driven by cost rather than high performances in terms of energy density. Therefore, batteries with alternative chemistry, complementary to and not competing with the lithium-ion battery technology are necessary.[2,3]

Recently, sodium-ion batteries have attracted large attention since, in principle, suitable to match the economic and environmental issues due to the high abundance and low cost of the employed materials.[4,5]Herein, we report a study on P-type layered sodium transition metal-based oxides, of the composition Na_xMO₂ (M=Ni, Fe, Mn), used as cathode materials for sodium-ion batteries employing a 1M NaPF₆ in propylene carbonate (PC) as electrolyte solution.[6] Indeed, P-type layered oxides appear to be very promising in terms of high delivered capacity. [7,8] We synthesize the materials via co-precipitation method followed by an annealing step in air and a water rinsing process. Following, we fully investigate the effect of Ni to Fe ratio, annealing temperature and sodium content on the electrochemical performances of the electrodes. The impact of these parameters on the structural and electrochemical properties of the materials is revealed by X-ray diffraction, scanning electron microscopy and cyclic voltammetry, respectively. The suitability of this class of P-type materials for sodium battery application is finally demonstrated by cycling tests revealing an excellent electrochemical performance, with a delivered capacity of about 200 mA h g^-1and charge-discharge efficiency approaching 100 %.

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[2] J.-M. Tarascon, Nat. Chem., 2, 510 (2010) ;

[3] B. W. Jaskula , Lithium, in Mineral Commodity Summaries 2012 , U. S. Geological Survey , Reston, VA 2012 , p. 94;

[4] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonzalez, T. Rojo, Energy Environ. Sci., 5, 5884 (2012);

[5] S.-W. Kim, D.-H. Seo, X. Ma, G. Ceder, K. Kang, Adv. Energy Mater., 2, 710 (2012);

[6] I. Hasa, D. Buchholz, S. Passerini, J. Hassoun, ACS Appl. Mater. Inte., (2015) in press;  

[7] I. Hasa, D. Buchholz, S. Passerini, B. Scrosati, J. Hassoun, Adv. Energy Mater. 2014, doi:10.1002/aenm.201400083;

[8] N. Yabuuchi, M. Kajiyama, J. Iwatate, H. Nishikawa, S. Hitomi, R. Okuyama, R. Usui,Y. Yamada, S. Komaba, Nature Mater., 11, 512 (2012);