▎ 摘　　要

NOVELTY - An electrochemical device includes a positive electrode sheet and an electrolyte. The positive electrode sheet includes a current collector (1), and a first coating layer (2) and a second coating layer (3) sequentially arranged on surface of the current collector. The first coating layer contains lithium manganate. The residual alkali value (R) on surface of the second coating layer and water content (H) in the electrolyte satisfy preset relation. USE - Electrochemical device used for electronic device (claimed). ADVANTAGE - The electrochemical device can effectively reduce dissolution of manganese, for improving damage to anode interface and loss of irreversible storage capacity caused by dissolution of manganese. DETAILED DESCRIPTION - An electrochemical device includes a positive electrode sheet and an electrolyte. The positive electrode sheet includes a current collector, and a first coating layer and a second coating layer sequentially arranged on surface of the current collector. The first coating layer contains lithium manganate. The residual alkali value (R) on surface of the second coating layer and water content (H) in the electrolyte satisfy the relation: Rgreater than or equal to10.3+1gH, where H is in ppm. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the positive electrode sheet. Current collector (1) First coating layer (2) Second coating layer (3)