▎ 摘　　要

NOVELTY - Lithium-ion mixed capacitor based on mesoporous polydopamine/graphene composite material comprises a positive electrode and a negative electrode, where the positive electrode is prepared from a positive electrode material, and/or the negative electrode is prepared from a negative electrode material, the positive electrode material comprises polydopamine/graphene composite material, the negative electrode material comprises mesoporous carbon nanosheets, the mesoporous carbon nanosheets are obtained by carbonization of polydopamine/graphene composite materials, the polydopamine/graphene composite material is prepared by polymerizing the mixture containing the graphene source, the dopamine compound and the mesoporous templating agent in presence of an acid-base buffer or an initiator, and removing the mesoporous templating agent to obtain the polydopamine/graphene composite material, and the mesoporous template agent is a diblock copolymer and/or a triblock copolymer. USE - The lithium ion mixed capacitor based on mesoporous poly-dopamine/graphene composite material is used in mobile phone, notebook computer, digital camera and other portable fast electronic equipment. ADVANTAGE - The poly-dopamine/graphene composite material in the lithium ion mixed capacitor has rich hole structure, improves the transmission speed, so the composite material has higher power density and better multiplying power performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the lithium-ion mixed capacitor, which involves (i) preparing polydopamine/graphene composite material, (ii) carbonizing the polydopamine/graphene composite material to obtain mesoporous carbon nanosheets, (iii) pre-inserting lithium on the negative electrode prepared from the mesoporous carbon nanosheets, and (iv) using the polydopamine/graphene composite material as the positive electrode material to prepare the positive electrode, using the mesoporous carbon nanosheets after pre-lithiation as the negative electrode, and combining with the lithium ion electrolyte to form the lithium ion mixed capacitor.