Sodium vanadate nanowires @ polypyrrole with synergetic core-shell structure for enhanced reversible sodium-ion storage

Abstract

Use of hybridized transition-metal oxides nanostructures with a shell coating show promise for improving the electrochemical performance of sodium-ion batteries. Herein, a novel type of designed sodium vanadate @ polypyrrole (Na5V12O32@PPy) nanocomposites with a synergetic core-shell structure was fabricated using sequential hydrothermal and electrodeposition methods. When the Na5V12O32@PPy nanocomposites were employed as a cathode, the assembled sodium-ion batteries exhibited a high reversible discharge capacity of 213 mAh g−1 at a current density of 30 mA g−1, high rate performance (133 mAh g−1 at 480 mA g−1) and superior cycling performance (202 mAh g−1 at 100 mA g−1 after 100 cycles with a capacity retention of 94%). By contrast, the cycling behavior of this novel material proved to be much better than the naked Na5V12O32 nanowires. This research provides a new pathway to explore cathode materials for sodium-ion battery with enhanced electrochemical performance.