Exploration of amorphous hollow FeOOH@C nanosphere on energy storage for sodium ion batteries

Abstract

Abstract Sodium ion batteries (SIBs) have enjoyed a high profile in recent years and gradually been commercialized to supplement the lithium-ion batteries system. However, the large volume expansion of anode materials within discharging and low electrical conductivity hinder the application of SIBs. In this work, a FeOOH@C composite was synthesized with the use of hydrothermal method and pyrolyzing of polydopamine. The amorphous FeOOH exhibits a hollow spherical structure to offer free space for buffering the volumetric variation. Furthermore, the outer carbon served as a protective shell could maintain the sphere integrity and enhance the electrical conductivity. Hence, benefiting from the achieved synergy of the hollow architecture, amorphous structure and carbon shell, the composite presented a long cycle life (316\xa0mA\xa0h\xa0g−1 after 500 cycles at a current density of 100\xa0mA\xa0g−1 and 234.5\xa0mA\xa0h\xa0g−1 after 400 cycles at 2\xa0A\xa0g−1) and high-rate performance (180\xa0mA\xa0h\xa0g−1 at 5\xa0A\xa0g−1), revealing a potential to be a promising candidate for electrode material of SIBs.