▎ 摘　　要

NOVELTY - Composite film comprises a copper foil and a graphene foam layer coated on the copper foil. USE - Composite film capable of regulating and controlling heat conduction and lithium-ion battery e.g. lithium-ion polymer battery. Can also be used in lithium-ion electrolyte battery. ADVANTAGE - The composite film: has good bonding with graphite cathode material during coating; changes thermal conductivity with the change of compression ratio; can significantly improve the specific surface area and electrical conductivity of the copper foil; increases thermal conductivity when the stress is increased; achieves rapid heat dissipation; and reduces the thermal conductivity when the stress is reduced, which can achieve the effect of thermally insulating ; reduces the low temperature caused by the battery capacity decay and lithium safety of the risk, reduces the internal impedance difference by presence of temperature gradient in battery, reduces current distribution in the charging and discharging process of the battery, and reduces the internal impedance of the lithium ion batteries. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a preparation method of composite film; and (2) a lithium ion battery.