Preparation method of carbon aerogel, carbon aerogel and application of carbon aerogel

The invention discloses a preparation method of carbon aerogel, the carbon aerogel and application of the carbon aerogel. The method comprises the following steps: adding water-soluble phenolic resin into water, heating and uniformly stirring to obtain a phenolic solution, cooling to room temperature, adding a basic catalyst and ceramic whiskers into the phenolic solution, and reacting for a period of time to obtain phenolic sol; placing the phenolic aldehyde sol at a certain temperature for a period of time, and enabling the phenolic aldehyde sol to be gelated to obtain phenolic aldehyde wet gel; placing the phenolic aldehyde wet gel in an autoclave, adding water, sealing the autoclave, heating the wet gel and water in the autoclave to a high-temperature and high-pressure state together, keeping for a period of time, and slowly discharging fluid in the autoclave until the pressure in the autoclave is 0 to obtain phenolic aldehyde aerogel; and placing the phenolic aerogel in a high-temperature furnace, vacuum