Sponge-like NaFe2PO4(SO4)2@rGO as a high-performance cathode material for sodium-ion batteries

Abstract

The traditional methods of preparing cathode materials usually require long time consuming and high temperature annealing, which consume a lot of material and financial resources. Herein, we report an ultrafast self-propagating combustion process to prepare a sponge-like NaFe₂PO₄(SO₄)₂@reduced graphene oxide (NFPS@rGO) material with favorable surface characteristics. This product is successfully prepared in a short time and is well coated with reduced graphene oxide due to its loose porous surface structure. Benefiting from the carbon coating, NFPS@rGO demonstrates an enhanced rate and cyclic performance than that of the pristine NFPS. The discharge specific capacity of NFPS@rGO still retains 43.4 mA h g⁻¹ at a high current density of 500 mA g⁻¹. After 100 cycles at 50 mA g⁻¹, the capacity retention of NFPS@rGO is 83.3%, which is also higher than NFPS by 34.7%. In addition, the fabricated hard carbon‖NFPS@rGO full-cell exhibits a favorable rate and cyclic performance. This study provides meaningful guidance for the modification of cathode materials for sodium-ion batteries and promotes its practical possibility.