Self-standing Co_2.4Sn_0.6O₄ nano rods as high performance anode materials for sodium-ion battery and investigation on its reaction mechanism

The self-standing nanorod Co_2.4Sn_0.6O₄ is synthesized as a high-performance anode material in search of high capacity and stable anode materials for sodium-ion batteries. The Co_2.4Sn_0.6O₄ nanorod exhibits a high reversible capacity of 576 mAh g⁻¹ at a current density of 80 mA g⁻¹ and shows excellent high-rate capability. The X-ray absorption spectroscopy study reveals the mechanisms of charge storage reaction and improved cycling performance of Co_2.4Sn_0.6O₄. A partially limited conversion reaction of Co– and Sn-oxide during the cycling effectively regulate the irreversible capacity loss over the cycling that is commonly observed from the conversion and alloying reaction-based anode materials. Furthermore, Co_2.4Sn_0.6O₄ also exhibits superior sodium-ion full cell performance when coupled with a NaNi_2/3Bi_1/3O₂ cathode, demonstrating an energy density of 262 Wh kg⁻¹.