Carbonaceous material and preparation method therefor, and secondary battery and electrical device comprising same

A method for preparing a carbonaceous material, comprising the following steps:

• S10, providing a raw material which is an organic carbon source;
• S20, crushing the raw material to a required particle size;
• S30, washing and removing impurities, performed by washing the crushed raw material obtained in S20 to remove impurities, wherein the washing and removing impurities process comprises at least an acidic solution washing step and an alkaline solution washing step;
• and
• S40, carbonizing, performed by placing, in a furnace, the raw material obtained in S30 after washing and removing impurities, introducing a protective gas containing hydrogen, controlling furnace pressure to ≤−2 kPa relative to standard pressure, then heating at a rate of ≤1° C./min to a target temperature T1, and maintaining the target temperature T1 for a target time t1 to obtain a carbonaceous material, wherein the carbonaceous material has 0.13≤A/B≤0.50, wherein A represents a mass of water vapor adsorbed on the carbonaceous material after a water vapor adsorption test by placing the carbonaceous material under constant temperature and humidity conditions of 25° C. and 100% RH for 100 h, and B represents an initial mass of the carbonaceous material.