Method for preparing active carbon fiber material with energy storage characteristic from polyacrylonitrile-based pre-oxidized fiber and application of active carbon fiber material

The invention discloses a method for preparing an active carbon fiber material with energy storage characteristics from a polyacrylonitrile-based pre-oxidized fiber and an application of the active carbon fiber material, and belongs to the technical field of active carbon fiber materials and electrochemical capacitors. The method comprises the following steps of: (1) cleaning the polyacrylonitrile-based pre-oxidized fiber (commercially available) by using water, and drying; (2) mixing the polyacrylonitrile-based pre-oxidized fiber dried from the step (1) with strong alkali in proportion, adding a certain amount of water, uniformly mixing, drying, controlling the temperature rise speed, and activating to obtain an activation product; (3) soaking the activation product obtained from the step (2) in hot water, filtering, washing until the solution is neutral, carrying out vacuum drying, and grinding into powder to obtain the active carbon fiber material capable of being used for the electrochemical capacitors. The active carbon fiber prepared through the method disclosed by the invention achieves the specific area to 1200-2500 m /g, is narrow in pore diameter distribution, achieves the mesoporous ratio by 20%-60%. The prepared active carbon fiber material as an electrode can be used for symmetrical type electrochemical capacitors or dissymmetric type electrochemical capacitors.