Exploration of anode materials with excellent electrochemical properties is essential to improve the performance of sodium ion batteries (SIBs). High -entropy oxide (HEO), with their unique structural characteristics, tailorable chemical composition and tunable functional properties, have drawn increasing interest in the fields of environmental science and renewable energy technology. However, directly using high entropy oxides as anode materials

for sodium ion batteries, a problem of agglomeration limits the electrochemical performance. In general, Carbon nanotube (CNT) are used to optimize battery performance due to their high electrical conductivity and good mechanical stability. Based on this, spinel -type highentropy oxide (FeCoNiCuMn)3O4/CNT composites (HEO/CNT) with space group Fd-3m have been successfully synthesized through hydrothermal followed by annealing method. As

the anode material in SIBs, with a current density of 0.5A·g-1, HEO/CNT has a reversible capacity of 231 mAh·g-1after 200 cycles. Additionally, the HEO/CNT exhibit high reversible capacities of 363.3, 350, 341.1, 310.2, and 290.2 mAh·g-1at the current densities 0.1, 0.2, 0.5, 1, and 2 A·g-1, respectively. In situ X-ray diffraction analysis has been employed to reveal that the sodium ion storage process is a result of a combined Na+intercalation and conversion reaction between Na+and HEO/CNT. Due to the "high entropy effect" of the high entropy oxide/carbon material, the volume change of the active material is mitigate d during the charge/discharge process. Therefore, HEO/CNT is expected to be an electrode material with good sodium storage performance. It also provides a new template strategy for the application of high entropy materials.