Electrochemical Mechanism and Effects of Fe Doping On Electrochemical Properties of Na2Co1-xFexSiO4 Cathode Material for Sodium-Ion Batteries

Sodium-based orthosilicates are considered promising candidates as positive electrode materials for rechargeable sodium-ion batteries (SIBs). Na2Co1-xFexSiO4 (NCFS), with x = 0.1 and 0.2 cathode materials have been synthesized by low cost method (improved solid-state). The prepared NCFSs cathodes are indexed based on the orthorhombic system with Pca2 1 space group. Na2Co0.8Fe0.2SiO4 demonstrated an initial discharge capacity at C/50 of 131.4 mAh.g −1 (1C = 272.7 mA.g −1) that is two times higher than that of the Na2Co0.9Fe0.1SiO4 (54.6 mAh.g −1 (1C = 272.27 mA.g −1)). All the above features and insights make the new materials highly promising for use as potential cathode material for SIBs.
This newly confected orthosilicate NCFS2 with ordered cations of Co/Fe shows a good structural stability during cycling and exhibits a single-phase solid-solution behavior during the charge/discharge process.