Method for preparing all-solid-state polymer electrolyte through in-situ thermal initiation and application

Abstract

The invention relates to a method for preparing an all-solid-state polymer electrolyte through in-situ thermal initiation and application of the all-solid-state polymer electrolyte in a lithium battery, and belongs to the field of lithium batteries. The method is characterized by comprising the following steps: preparing a mixed solution consisting of a polyethyleneimine polymer, unsaturated bond-containing terminal acid ester, salt and a solvent; putting the mixed solution into a closed container, and carrying out in-situ thermal initiation crosslinking under the condition of not adding an initiator to form a polymer electrolyte, wherein the weight ratio of the polyethyleneimine polymer to the unsaturated bond end group-containing acid ester is 2-4:1, and the weight ratio of the sum of the use amounts of the polyethyleneimine polymer and the unsaturated bond end group-containing acid ester to the use amount of the salt is 1:3-3:1, the balanced being solvent. The invention aims to solve the technical problems that the use of an initiator is required, the salt selectivity is limited, and the temperature condition is higher.

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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