Method and Application of In-Situ Thermal Initiation Preparation of All-Solid Polymer Electrolyte

Abstract

The invention relates to a method for preparing an all-solid polymer electrolyte by in-situ thermal initiation and its application in lithium batteries, which belongs to the field of lithium batteries, and is characterized in that it comprises the following steps: preparing polyethyleneimine polymers, A mixed solution composed of an ester of an unsaturated bond terminal group, a salt, and a solvent; the mixed solution is placed in a closed container, and the in-situ thermally initiated crosslinking is performed without adding an initiator to form a polymer electrolyte; the said The weight ratio of polyethylenimine polymer and ester containing unsaturated bond end group is 2-4:1, the sum of the amount of polyethylenimine polymer and unsaturated bond end group ester and the amount of salt The weight ratio of the compound is 1:3-3:1, and the balance is a solvent; the present invention aims to solve the technical problems of requiring the use of an initiator, limited selectivity to salts, and high temperature conditions.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method and application of an all-solid-state polymer electrolyte prepared by in-situ thermal initiation. Background technique [0002] In recent years, with the rise of electric vehicles and the urgent need for large-scale energy storage devices for renewable energy power generation, the research on lithium batteries has heated up again, and the development of safe, large-capacity, high-power and long-life secondary lithium batteries has become the focus . As lithium-ion batteries need to meet the requirements of long cruising range and high-power charging and discharging, safety is particularly important. At present, commercial lithium-ion batteries release a large amount of heat when a short circuit occurs, which will ignite the organic electrolyte and cause an explosion hazard, which is obviously difficult to be widely used. All-solid-state lithium batteries have...

AI Technical Summary

Problems solved by technology

All of these solid polymer electrolytes are prepared by pre-preparing polymer films and then assembled into batteries by winding or stacking the positive and negative electrodes of the battery, which leads to a gap between the battery poles / solid electrolyte The solid / solid interface impedance is very large, and the charge and discharge performance, rate and cycle performance of solid-state batteries are relatively poor

[0003] In the prior art, the publication number is CN110459802A, which discloses in-situ heat-initiated cross-linking to prepare polymer electrolytes and all-solid-state sodium-ion batteries to contain sodium salts, initiators, film-forming additives, and flame retardants. Acrylic acid ester PEGMEMA mixed solution is used as raw material for in-situ thermal initiation to prepare all-solid-state sodium-ion batteries, but such things require the use of initiators, otherwise the reaction cannot proceed normally; in addition, the system also has a certain selectivity for salts.

Publication No. 110071328A discloses a cross-linked polyethyleneimine solid electrolyte and its application. First, the modified monomer is introduced into polyethyleneimine to obtain modified polyethyleneimine, and then the modified polyethyleneimine is combined with crosslinked The polymer solid electrolyte is obtained through heating and cross-linking reaction of lithium salt and lithium salt. The temperature of the heating and cross-linking reaction needs to be 70-140°C, which is a relatively high temperature condition. In addition, polyethyleneimine needs to be grafted and modified, but the modified The grafting rate cannot be precisely controlled, so it is not suitable for direct in-situ preparation of polymer batteries, and at the same time increases the preparation cost of polymer electrolytes

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