Composite solid electrolyte and preparation method thereof

Abstract

The invention belongs to the technical field of solid electrolytes, and particularly relates to a composite solid electrolyte and a preparation method thereof. The method comprises the steps: enablingpolyether glycol, 2, 6-toluene diisocyanate, a catalyst and a chain extender to be mixed and react to obtain a polyurethane prepolymer; in an inert gas atmosphere, dispersing a lithium salt and an inorganic solid electrolyte into 1, 3-dioxolane, adding an initiator and a plasticizer, and performing uniform dispersing to obtain a precursor solution; and adding the precursor solution into the polyurethane prepolymer, performing stirring and mixing uniformly, performing standing, performing heating to 70-75 DEG C, and keeping the temperature for 6-8 hours to obtain the composite solid electrolyte. According to the invention, the 1, 3-dioxolane takes the lithium salt additive as a ring-opening initiator, the coating of the inorganic solid electrolyte is performed in the ring-opening polymerization process, and a mutually doped networked polymer with a polyurethane system is formed, so the formed networked porous structure has a rich ion transport network, and the ion transport property and the electron conductivity are improved.

Description

technical field [0001] The invention belongs to the technical field of solid electrolytes, and in particular relates to a composite solid electrolyte and a preparation method thereof. Background technique [0002] In recent years, lithium-ion secondary batteries have received widespread attention as a recyclable clean energy source. Traditional lithium-ion batteries use carbonate-based organic liquid electrolytes, even at lower current densities than diffusion, and metal Electrochemical performance and safety are limited by the chemical stability of the liquid electrolyte in contact with the negative electrode, where continuous reactions of the liquid electrolyte lead to depletion of the electrolyte and increased interfacial impedance, in addition, indirect processes generated by current-induced internal short circuits may also lead to battery failure ; That is, the traditional lithium-ion battery has the disadvantages of poor stability, easy corrosion, flammability and expl...

AI Technical Summary

Problems solved by technology

[0002] In recent years, lithium-ion secondary batteries have received widespread attention as a recyclable clean energy source. Traditional lithium-ion batteries use carbonate-based organic liquid electrolytes, even at lower current densities than diffusion, and metal Electrochemical performance and safety are limited by the chemical stability of the liquid electrolyte in contact with the negative electrode, where continuous reactions of the liquid electrolyte lead to depletion of the electrolyte and increased interfacial impedance, in addition, indirect processes generated by current-induced internal short circuits may also lead to battery failure That is to say, the traditional lithium-ion battery has the disadvantages of poor stability, easy corrosion, flammability and explosion, and with the frequent occurrence of lithium-ion battery safety accidents, the safety of lithium-ion batteries has been paid more and more attention by people

[0003] In response to the problems caused by the use of organic liquid electrolytes in traditional lithium-ion batteries, researchers have proposed many solutions, such as the use of flame retardant additives, gel electrolytes and polymer solid electrolytes, which can improve the safety of lithium batteries to a certain extent However, this problem cannot be completely solved, and the use of inorganic solid electrolytes instead of organic electrolytes is expected to completely solve the two key problems of traditional lithium-ion batteries: low capacity and short service life. Therefore, all-solid-state lithium batteries with solid electrolytes replacing traditional liquid organic electrolytes are attracting more and more attention