▎ 摘　　要

NOVELTY - Composite lithium metal cathode comprises three-dimensional carbon-based current collector comprising a porous structure. The lithium metal attached to the three-dimensional carbon-based current collector surface and inner hole, and protective film covering the lithium metal. The protective film comprises a lithium metal and a lithium salt. The lithium metal is metal capable of being replaced by lithium metal. The composite lithium metal cathode in the first charging and discharging process reacts with the electrolyte to form stable solid electrolyte phase interface, where the solid electrolyte phase interface will not be decomposed in the subsequent charging and discharging process. USE - The composite lithium metal is useful in preparing metal secondary electrode (claimed), cathode of lithium battery e.g. lithium ion battery and lithium polymer battery. ADVANTAGE - The composite lithium metal has good cycle life and performance, is prepared in simple and cost-efficient manner. The lithium metal particles in the composite cathode provides a lithium-philic site, reduces nucleation energy barrier of lithium ion, and induces lithium ion to be uniformly deposited. The solid electrolyte phase interface (SEI) film does not continuously break and reconstruct in the multiple circulation process to consume electrolyte and lithium metal, and avoids irreversible attenuation of the battery capacity. The three-dimensional carbon-based current collector relieves cathode volume strain, induces lithium uniform deposition and lithium metal expansion in the circulation process, controls concentration of the lithium salt solution in certain range, avoids lithium dendritic crystal growth, and forms stable SEI interface protection effect. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing a composite lithium metal cathode, comprising using lithium metal salt solution with solute composed of at least one of aluminum fluoride, aluminum chloride, aluminum sulfide, zinc sulfate, aluminum nitride, aluminum nitrate, magnesium chloride, magnesium sulfide, magnesium sulfate, magnesium nitrate, zinc fluoride, zinc chloride, zinc sulfide, zinc sulfate, zinc nitrate, tin dichloride, tin tetrachloride, tin difluoride, tin tetrafluoride, tin sulfate, tin nitrate, silver fluoride, silver chloride, silver sulfate, silver nitrate and fluoroacetic acid. The solvent in the lithium metal salt solution is at least one of ethanol, water and acetone; and (2) metal secondary battery.