CN-121983657-A - Preparation method for cooperatively constructing composite solid electrolyte interface layer by aminated dendritic mesoporous silica and lithium polyacrylate

CN121983657ACN 121983657 ACN121983657 ACN 121983657ACN-121983657-A

Abstract

The invention designs an organic-inorganic composite solid electrolyte interface layer based on an electrostatic self-assembly strategy, which is used for realizing high-density dendrite-free lithium deposition on the surface of a lithium metal anode. The composite interface layer is cooperatively constructed by amino dendritic mesoporous silica and lithium polyacrylate, so that a nano-scale composite structure of rigid framework-flexible bonding is formed. NH2-DMS is used as a rigid framework to establish a three-dimensional interconnected mesoporous channel for homogenizing lithium ion flow, PAALi is used as a flexible matrix, and continuous interface self-healing is realized through dynamic reversible carboxylate-lithium ion bonding. The structure can obviously improve the ionic conductivity and the mechanical strength of the interface, thereby effectively inhibiting the growth of lithium dendrites.

Inventors

MEI TAO
YAO HONGLING
FAN SHUTING
JIA LINA
Chang Shuya

Assignees

湖北大学

Dates

Publication Date: 20260505
Application Date: 20251030

Claims (5)

1. The preparation method for constructing the composite solid electrolyte interface layer by the cooperation of the aminated dendritic mesoporous silica and the lithium polyacrylate is characterized by comprising the following steps of: S1, preparing amino dendritic mesoporous silica, namely reacting tetraethyl orthosilicate with a mixed template agent consisting of cetyl trimethyl ammonium bromide and sodium salicylate by using triethanolamine as a catalyst to prepare a precursor solution, then refluxing in an ethanol/HCl solution to remove a template to obtain dendritic mesoporous silica, then reacting with 3-aminopropyl triethoxysilane in an ethanol/acetic acid mixture to perform amino functionalization, and finally freeze-drying to obtain amino dendritic mesoporous silica which is denoted as NH 2 -DMS; S2, preparing lithium polyacrylate, namely controlling the molar ratio of the polyacrylic acid to the lithium hydroxide to be 1:1, carrying out a neutralization reaction, and preparing the lithium polyacrylate, which is recorded as PAALi; S3, preparing an amino dendritic mesoporous silica and lithium polyacrylate composite solid electrolyte interface layer, namely uniformly mixing NH 2 -DMS prepared in the step S1 and PAALi prepared in the step S2 according to a mass ratio of 1:1, and constructing an amino dendritic mesoporous silica and lithium polyacrylate composite material by means of electrostatic self-assembly action between the NH 2 -DMS@PAALi; Wherein, the rigid NH 2 -DMS framework in the NH 2 -DMS@PAALi solid electrolyte interface layer establishes a mesoporous channel which is three-dimensionally interconnected, thus enhancing the homogenization distribution of lithium ions, and the flexible PAALi chain provides dynamic reversible bonding between carboxylic acid and lithium ions, thus enhancing the transmission of lithium ions.
2. The preparation method of the composite solid electrolyte interface layer constructed by the cooperation of the aminated dendritic mesoporous silica and the lithium polyacrylate is characterized in that the reaction temperature of the precursor solution in the step S1 is 80 ℃, the reaction time is 2 hours, the solvent is 100mL of ethanol solution containing 1mL of concentrated hydrochloric acid when the template is removed, the reaction temperature is 60 ℃, and the reaction time is 24 hours.
3. The preparation method of the composite solid electrolyte interface layer constructed by the cooperation of the aminated dendritic mesoporous silica and the lithium polyacrylate is characterized in that 100mL of ethanol solution containing 1mM acetic acid is used in the step S1 of amino functionalization, the reflux temperature is room temperature, and the reaction time is 12 hours.
4. The preparation method of the composite solid electrolyte interface layer constructed by the cooperation of the aminated dendritic mesoporous silica and the lithium polyacrylate is characterized in that the same concentration of the aminated dendritic silica and the lithium polyacrylate dispersion liquid is prepared in the step S3, the reaction atmosphere is inert gas, the reaction temperature is room temperature, and the reaction time is 6 hours.
5. A lithium metal artificial solid electrolyte interface layer is characterized in that the amino dendritic mesoporous silica and lithium polyacrylate composite solid electrolyte interface layer prepared by the preparation method of any one of claims 1-4 is used for modifying lithium metal as a negative electrode material, so that growth of lithium dendrites and side reactions can be inhibited, and the cycle life and electrochemical performance of a lithium metal battery are improved.

Description

Preparation method for cooperatively constructing composite solid electrolyte interface layer by aminated dendritic mesoporous silica and lithium polyacrylate Technical Field The invention relates to the field of manufacturing of key materials of lithium metal batteries, in particular to an amino dendritic mesoporous silica and lithium polyacrylate composite solid electrolyte interface layer, a preparation method and application thereof. Background Lithium metal anodes are considered the final choice for the next generation of high energy density battery systems due to their extremely high theoretical specific capacity (3830 mAh g-1) and the lowest electrochemical potential (-3.04V vs. Standard hydrogen electrode). However, commercial applications of lithium metal batteries have long been severely limited by two interrelated key issues, the formation of unstable solid electrolyte interphase by spontaneous reaction between metallic lithium and electrolyte, and uncontrolled growth of lithium dendrites during cycling. Unstable solid electrolyte interface layers are generally low in mechanical strength, nonuniform in chemical composition, and difficult to withstand large volume changes during lithium deposition/exfoliation, resulting in repeated cracking of the solid electrolyte interface layers. The broken solid electrolyte interface layer exposes new lithium surfaces, continues to consume electrolyte and exacerbates the increase in interface resistance, and also causes localized current density maldistribution, inducing further growth of lithium dendrites. Not only may sharp lithium dendrites puncture the separator causing a short circuit in the cell, the "dead lithium" formed after its breakage may also cause rapid capacity decay and cell failure. Disclosure of Invention Aiming at the problems, the invention provides a composite solid electrolyte interface layer which is constructed by the cooperation of aminated dendritic mesoporous silica and lithium polyacrylate, and the solid electrolyte interface layer is composited by electrostatic self-assembly, so that the interfacial cohesive force can be enhanced, and lithium metal cations can be protected. The amination dendritic mesoporous silica component has a three-dimensional interconnection mesoporous framework with ultrahigh specific surface area, and is an effective ion diffusion channel for uniformly distributing lithium ions. Meanwhile, carboxylic acid in the lithium polyacrylate and lithium ions form a dynamic reversible bond, and the key is that a flexible lithium polyacrylate chain is anchored on a rigid amino dendritic mesoporous silica bracket through strong electrostatic interaction, so that the interfacial cohesion is enhanced. The synergistic integration creates a continuous lithium ion permeable network by coupling the ion dissociative groups of the lithium polyacrylate with the ordered mesochannels of the amino dendritic mesoporous silica, thereby achieving the purpose of improving the electrochemical performance of the battery. In order to achieve the above object, the present invention provides the following technical solutions: The preparation method for constructing the composite solid electrolyte interface layer by the cooperation of the aminated dendritic mesoporous silica and the lithium polyacrylate comprises the following steps: Step one, preparing dendritic mesoporous silica, namely reacting tetraethyl orthosilicate with a mixed template agent consisting of hexadecyl trimethyl ammonium bromide and sodium salicylate by using triethanolamine as a catalyst, preparing a precursor solution at a reaction temperature of 80 ℃ for 2 hours, dispersing the obtained product in 100mL of ethanol solution containing 1mL of concentrated hydrochloric acid, refluxing to remove the template, and reacting at a reaction temperature of 60 ℃ for 24 hours to obtain the dendritic mesoporous silica. Step two, preparing amino dendritic mesoporous silica, namely reacting the dendritic mesoporous silica in the step one with 3-aminopropyl triethoxysilane in an ethanol/acetic acid mixed solution, wherein the concentration of acetic acid is 1mM, performing amino functionalization, and finally performing freeze drying to obtain the amino dendritic mesoporous silica. And thirdly, preparing lithium polyacrylate, namely controlling the molar ratio of the polyacrylic acid to the lithium hydroxide to be 1:1, and carrying out a neutralization reaction to prepare the lithium polyacrylate. And step four, preparing a composite solid electrolyte interface layer, namely uniformly mixing the amination dendritic mesoporous silica prepared in the step one with the lithium polyacrylate prepared in the step two in a mass ratio of 1:1 in an inert atmosphere, and constructing a composite through electrostatic self-assembly action between the amination dendritic mesoporous silica and the lithium polyacrylate. Compared with the prior art, the invention has the following obvious outstand