▎ 摘　　要

NOVELTY - Electrochemical device has positive electrode. The positive electrode includes positive electrode active material layer. The positive electrode active material layer includes a positive electrode active material and a composite carbon material. The volume of the positive electrode active material layer is the first volume, and the volume of pore with a pore diameter of less than 2 microm in the positive electrode active material layer is the second volume, where second volume/first volume is 14-20%. USE - Electrochemical device used in electronic device (claimed). ADVANTAGE - The composite carbon material in the positive active material layer has play a role in structural bonding and pore-forming, and second volume/first volume is more than or equal to 14%, so that the formed positive electrode has rich pore channels for lithium ion transmission, and the rate capability of an electrochemical device formed by the positive electrode is improved.