The invention provides a preparation method of a
lithium surface artificial SEI and a protective film. The core of the method is to synthesize an artificial SEI, and the artificial SEI comprises an
organic polymer and a porous material. Wherein the
organic polymer is poly (2, 2, 6, 6-tetramethyl-1-
piperidine epoxy-4
alkyl acrylate) (PTPA), not only can be ionized in situ to generate cation free radicals and inhibit anion movement, but also can be used as an
electron transfer
mediator to optimize the selective transport of Li < + > and accelerate the migration of
lithium ions; the high specific surface area and rich pore structure of the porous material not only have an
ion screening function, but also can provide more transmission channels for
lithium ions, so that the
diffusion efficiency of the lithium ions is improved,
volume change can be buffered, mechanical support can be provided to inhibit the growth of lithium dendrites, the flexibility and
mechanical stability of the SEI membrane are enhanced, and the service life of the SEI membrane is prolonged. The method can adapt to the
volume change of the
lithium metal electrode in the charging and discharging process, and the electrochemical performance of the
metal lithium battery is greatly improved.