▎ 摘　　要

NOVELTY - Ultra-thin lithium film composite comprises a bearing layer, a stress control layer located on the surface of the carrier layer, and ultra-thin lithium film composited with the support layer via the stress control layer. The ultra-thin lithium film is a uniform thin film having through holes with a diameter of 5-200 microns, a uniform thickness of 0.5-20 microns, and a thickness tolerance within ±0.5 µm. The adhesive force between the ultra-thin lithium film and the bearing layer is 0.5-15 N.m-1. USE - Ultra-thin lithium film composite for secondary battery. ADVANTAGE - The film composite is more easily attached to bearing layer and reduces the stress influence of rolling. The lithium film with through hole compared with the complete lithium film, can realize better prelithiation effect. Due to the presence of the through hole, the accumulation of the internal stress of the lithium film in the rolling process is relieved to a certain extent, so that lithium film does not easy to deform, so as to prepare a thinner uniform thickness of lithium film. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method of preparation-thin lithium film composite, which involves: (1) using roll-to-roll continuous production method; (2) using metal lithium strips with a thickness of 10-250 µm as raw materials; (3) rolling and compounding the metallic lithium strip on the stress control layer of the bearing layer with the stress control layer by rolling to obtain ultra-thin lithium film composite.