Preparation method and application of composite current collector for battery

The invention relates to a preparation method and application of a composite current collector for a battery, and aims to solve the problem of graphite falling caused by volume expansion, electrolyte reaction, cyclic stress and insufficient material adhesion of an existing graphite positive plate. The preparation method comprises the following steps: 1, laying the net-shaped substrate on the surface of the metal foil, putting the metal foil into a rolling machine, and carrying out rolling treatment, so that the metal foil and the net-shaped substrate are tightly combined to obtain a composite current collector; 2, preparing graphite slurry; and 3, uniformly coating the composite current collector with the graphite slurry, and drying. According to the dual-ion battery using the composite current collector, the problem that graphite on a positive plate falls off in the circulation process is solved, fixation of large-particle matter materials can be achieved, the number of active substances can be kept good, ba