Diaphragm for solid electrolyte of lithium battery and preparation method of diaphragm

Abstract

The invention discloses a diaphragm for a solid electrolyte of a lithium battery and a preparation method of the diaphragm, and belongs to the technical field of lithium ion batteries. The preparation method comprises the following steps: adding a lithium salt, a polymer electrolyte, a metal oxide, a surfactant and a binder into a solvent to obtain slurry 1; adding a lithium salt, a polymer electrolyte, a metal oxide, a surfactant, a binder, the surface grafted polymer brush magnesium borate nanowire and an organic tin stabilizer into a solvent to obtain slurry 2; coating the slurry 1 and the slurry 2 on the surfaces of the two sides of a base film respectively, and then drying; the magnesium borate nanowire is subjected to polymer brush grafting treatment, and the organic tin stabilizer is added, so that the solid electrolyte containing the magnesium borate nanowire can operate stably; the magnesium borate nanowires are added into the coating, close to the negative electrode of the lithium battery, of the diaphragm, so that the ionic conductivity of the electrolyte diaphragm is enhanced, and the problem of short circuit of the battery caused by growth of lithium dendrites at the negative electrode due to non-uniform deposition of lithium ions at the negative electrode is avoided.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a separator for a solid electrolyte of a lithium battery and a preparation method thereof. Background technique [0002] The development of electric vehicles, large-scale energy storage, and micro-devices requires the continuous improvement of the energy density and power density of existing secondary batteries. The advantages of high energy density have greatly attracted people's attention. However, the flammable organic liquid electrolytes used in conventional lithium-ion batteries can pose serious safety concerns. In addition, the large-scale applications of lithium batteries, such as new energy electric vehicles, smart grids, and large-scale energy storage, also face unprecedented challenges in terms of safety. Although various new electrolytes and protective measures have been adopted at present, the essential characteristics of the flammability o...

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Problems solved by technology

[0004] Magnesium borate nanowires are nanomaterials with good electrical conductivity and mechanical properties. Studies have shown that adding magnesium borate nanowires to the solid electrolyte of lithium batteries can enhance the conductivity of the electrolyte, and it is comparable to that without adding nanometers. Compared with the electrolyte with magnesium borate nanowires, the electrolyte with magnesium borate nanowires can withstand greater stress, but the study also found that although magnesium borate nanowires can improve the conductivity of the electrolyte, the electrolyte cannot operate stably at room temperature. Its cycle stability is poor, resulting in the inability of magnesium borate nanowires to be effectively popularized and applied in solid electrolytes for lithium batteries

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