Synchronous synthesis of Kirkendall effect induced hollow FeSe2/C nanospheres as anodes for high performance sodium ion batteries

Abstract

In this work, we have developed a simple and facile method to synchronously synthesize hollow FeSe₂/C nanospheres using the Kirkendall effect. When evaluated as an anode for SIBs, the hollow FeSe₂/C nanospheres exhibit a high discharge capacity retention of 474.1 mA h g⁻¹ at 0.05 A g⁻¹ (based on the calculation of FeSe₂), which is very close to the theoretical capacity of FeSe₂ (∼500 mA h g⁻¹). Meanwhile, hollow FeSe₂/C also has a superior rate capability of 364.5 and 316.5 mA h g⁻¹ even at 2.0 and 5.0 A g⁻¹, respectively. The high performance of the hollow FeSe₂/C nanospheres can be ascribed to the unique carbon coated hollow nanostructure.