Hard carbon, method for preparing same, secondary battery comprising same, and electrical apparatus comprising same

A method for preparing a hard carbon, comprising following steps:

• S10:
• providing a carbon source;
• S20:
• heat treating the carbon source in an inert atmosphere at a first temperature T1 for a duration of t1 to obtain a first intermediate product;
• S30:
• heat treating the resulting first intermediate product in an oxygen-containing atmosphere with an oxygen volume fraction greater than or equal to 25% at a second temperature T2 for a duration of t2 to obtain a second intermediate product;
• and
• S40:
• carbonizing the resulting second intermediate product in an inert atmosphere at a third temperature T3 for a duration of t3 to obtain the hard carbon,
• wherein an amount of generated CO2 is detected in thermal programmed desorption-mass spectrum (TPD-MS) to be less than or equal to 1.0 mmoL/g and an amount of generated CO is detected in thermal programmed desorption-mass spectrum to be less than or equal to 2.0 mmoL/g, when the hard carbon is heated from 50° C. to 1,050° C.