Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3
No Thumbnail Available
Date
2016-06-01
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The new compounds NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 crystallize with a stuffed α-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)3 the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 delivered specific capacities of 352, 385, and 368 mA h g−1, respectively, which attests to the electrochemical activity of sodium in these compounds. © 2016 Elsevier Inc.
Description
Keywords
Crystal structure, Neutron diffraction, Synthesis, Electric batteries, Anodes, Sodium ions, Electrodes, Sol-gel process
Citation
Ben Yahia, H., Essehli, R., Avdeev, M., Park, J-B., Sun, Y-K., Al-Maadeed, M. A., Belharouak, I. (2016). Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3. Journal of Solid State Chemistry, 238, 103-108, doi:10.1016/j.jssc.2016.03.011