▎ 摘　　要

NOVELTY - Preparing niobium-based metal oxide mesoporous carbon ball composite material with oxygen defect involves preparing niobium pentachloride ethanol solution, ultrasonically mixing uniformly to obtain solution A, adding the solution A into the mesoporous carbon ball, ultrasonically soaking to obtain precursor B. The obtained precursor B is placed in a vacuum oven to dry, placed the dried sample in a tubular furnace filled with hydrogen argon mixed gas, sintered at 450-750degrees Celsius, cooled to room temperature to obtain product represented as niobium oxide-x MEC, where the range of x is 0.1-0.5, and the volume ratio of the hydrogen is 5-20%. USE - Method for preparing niobium-based metal oxide mesoporous carbon ball composite material with oxygen defect used in developing the practical sodium ion battery and the material of the related energy storing and converting field. ADVANTAGE - 0.1-10:1,The method realizes the multiplying power performance of the 20A g-1 over 5000 times of the over-long circulating service life. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: 1. Sodium ion cathode material, comprises niobium-based metal oxide mesoporous carbon ball composite material with oxygen defect and 2. Sodium ion battery, comprises negative electrode made of the sodium ion cathode material.