Preparation method of activated carbon for supercapacitor, activated carbon and application thereof

The invention discloses a preparation method of activated carbon for a supercapacitor, activated carbon and application thereof. The preparation method comprises the following steps of (1) taking coal-based activated carbon as a raw material, crushing the coal-based activated carbon, and sieving the crushed coal-based activated carbon through a 325-mesh standard sieve, (2) uniformly mixing the powder obtained in the step (1) with hydrochloric acid and/or nitric acid, and carrying out acid dissolution treatment to remove ash, (3) carrying out solid-liquid separation after ash removal treatment in the step (2), washing and drying the obtained solid material, and then carrying out pre-oxidation treatment for 2-4 hours in an air atmosphere of 350-450 DEG C, (4) uniformly mixing a pre-oxidized material obtained after the pre-oxidation treatment with KOH and/or NaOH serving as an activating agent, and then activating in a nitrogen atmosphere at the activation temperature of 700-1000 DEG C, and (5) further performin