Titanium dioxide aerogel composite polymer electrolyte with high ionic conductivity and preparation method and application thereof
By combining titanium dioxide aerogel with cross-linked polyaniline to form a three-dimensional network structure, the problem of insufficient mechanical strength and ionic conductivity of polymer electrolytes is solved, achieving the effects of efficient suppression of lithium dendrites and high power output.
Patent Information
- Application Number
- CN202511509385.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-01-20
AI Technical Summary
Existing polymer electrolytes are inadequate in suppressing lithium dendrite growth and providing high power output. They also have poor mechanical strength and low ionic conductivity, which cannot meet the dynamic requirements of lithium batteries.
A composite polymer electrolyte with a three-dimensional network structure is formed by combining titanium dioxide aerogel with cross-linked polyaniline (PANI). Continuous ion transport channels are constructed by photocuring technology, and titanium dioxide is added to enhance mechanical properties.
It significantly improves the elastic modulus and ionic conductivity of the composite material, effectively suppresses lithium dendrite growth, and enhances the safety and power output capability of lithium batteries.
Smart Images
Figure CN121366933A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of electrochemistry, in particular to a titanium dioxide aerogel composite polymer electrolyte with high ionic conductivity and a preparation method and application thereof. BACKGROUND
[0002] Solid-state lithium (Li) batteries have a high energy density and show great potential for development in the field of next-generation energy storage devices. Currently developed electrolytes include polymer electrolytes, oxide electrolytes, sulfide electrolytes, and halide electrolytes. Among them, polymer electrolytes have attracted widespread attention due to their low density, low cost, and excellent processing characteristics. However, polymer-based systems generally have poor mechanical strength, which makes it difficult to effectively inhibit the formation of lithium dendrites. At the same time, the ionic conductivity of the polymer electrolyte at room temperature is relatively low, which cannot achieve the desired kinetic performance. To overcome the limitations of polymer electrolytes, inorganic fillers can be added to improve the ionic conductivity. However, in practical applications, inorganic fillers tend to agglomerate, which weakens their role in Lewis acid-base interaction systems, and thus the ionic conductivity of the polymer electrolyte treated in this way cannot reach the required level for battery kinetic operation. At the same time, inorganic fillers are difficult to form a connected reinforcing structure, which cannot effectively improve the mechanical properties of the composite material. In fact, there is a significant contradiction between ionic conductivity and elastic modulus in the polymer electrolyte system. Generally, to achieve high ionic conductivity, the polymer requires a lower crystallinity and a more fluid polymer chain. However, such characteristics weaken the mechanical properties of the polymer, resulting in a soft texture.
[0003] Therefore, the skilled person in the art is committed to developing a practical polymer electrolyte that can effectively inhibit lithium dendrite growth and provide high power output to properly solve this contradiction. SUMMARY
[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present application is to provide a practical polymer electrolyte that can effectively inhibit lithium dendrite growth and provide high power output to solve the above-mentioned technical problems.
[0005] In order to achieve the above technical purpose, the present application mainly adopts the following technical solutions: The present application discloses a preparation method of a titanium dioxide aerogel composite polymer electrolyte with high ionic conductivity, comprising the following steps: Step 11, configuring a premixed solution of polyaniline (PANI), succinyl cyanide (SCN), and lithium bisfluorosulfonylimide (LiFSI) as an electrolyte precursor; Step 12, inject the electrolyte precursor into the aerogel under vacuum-assisted conditions, and perform photocuring to form a cross-linked polymer; Step 13, add titanium dioxide to the cross-linked polymer, and uniformly mix to obtain a titanium dioxide aerogel polymer electrolyte.
[0006] In the preferred embodiment of the present application, in step 11, the molar ratio of the polyaniline PANI, succinonitrile SCN, and lithium bisfluorosulfonylimide LiFSI is 6:4:8.
[0007] In the preferred embodiment of the present application, in step 11, the electrolyte precursor is configured under an inert atmosphere.
[0008] In the preferred embodiment of the present application, in step 12, the vacuum condition is 0.1 MPa.
[0009] In the preferred embodiment of the present application, in step 12, the photocuring condition is 30 minutes of photocuring under 365 nm ultraviolet light.
[0010] In the preferred embodiment of the present application, in step 13, the amount of titanium dioxide added is 30% of the mass fraction of the electrolyte precursor.
[0011] The present application also discloses a titanium dioxide aerogel composite polymer electrolyte prepared by the above method.
[0012] The present application also discloses an application of the titanium dioxide aerogel composite polymer electrolyte as described above in the preparation of a lithium battery.
[0013] The present application also discloses a lithium battery containing the titanium dioxide aerogel composite polymer electrolyte as described above.
[0014] The present application also discloses a preparation method of the lithium battery as described above, comprising the following steps: Step 101, pour the titanium dioxide aerogel composite polymer electrolyte into a polytetrafluoroethylene mold or a glass plate, and form a uniform polymer electrolyte film by natural air drying or heating to volatilize the solvent; Step 102, cut the prepared polymer electrolyte film into a suitable size; Step 103, clamp the cut polymer electrolyte film between two stainless steel electrodes to ensure alignment; Step 103, place the stainless steel electrode and the film together in a button cell shell, seal and apply pressure using a sealing machine, and assemble to form a battery.
[0015] Compared with the prior art, the present application has the following beneficial effects: The application develops an innovative composite electrolyte system, the core structure of which is composed of a three-dimensional network titanium dioxide aerogel skeleton and a high-conductivity cross-linked polyaniline (PANI) based electrolyte. This unique structural design makes the elastic modulus and ionic conductivity of the composite material significantly improved. Compared with the composite electrolyte prepared by the traditional mechanical blending method (prepared by physically mixing ceramic fillers, polymer matrix and lithium salt), the structural design strategy adopted by the application shows significant differences in material construction method and performance characteristics.
[0016] The precursor construction strategy of the three-dimensional network of titanium dioxide aerogel plays a key role, effectively solving the multiple technical bottlenecks existing in the mechanical mixing system, including mechanical performance degradation, low ion conduction efficiency and ceramic filler agglomeration. Specifically, the innovative system shows three significant advantages: (1) Based on the high-strength interconnected titanium dioxide aerogel skeleton structure, the mechanical properties of the composite material are no longer excessively dependent on the mechanical strength of the polymer matrix, and the elastic modulus is improved by more than one order of magnitude compared with traditional polymer electrolytes; (2) The uniformly distributed ultra-fine titanium dioxide nanodomains and their surface acidic sites can interact specifically with lithium salt anions, forming continuous ion transport channels in the material, promoting the deep dissociation of lithium salt and the increase of ion migration number; (3) Under high temperature working conditions, the composite system can still maintain excellent mechanical rigidity, while traditional polymer electrolytes will show significant rigidity decay under this condition.
[0017] Based on the above synergistic effect, the ionic conductivity of the composite electrolyte is significantly improved, the elastic modulus of the composite electrolyte is at least one order of magnitude higher than that of the cross-linked PANI based electrolyte, and the hardness of the material is obviously enhanced. These performance improvements make the system exhibit excellent dendrite inhibition ability during long-term cycling, effectively avoiding the risk of internal short circuit.
[0018] The titanium dioxide aerogel reinforcement strategy proposed by the application not only verifies the design feasibility of constructing a strong and tough high-ionic-conductivity polymer electrolyte, but also provides an important material basis for the research and safe operation of the next generation of high-energy-density solid-state lithium batteries.
[0019] The concept, specific structure and technical effects of the application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the application. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 The figure provided by the application shows the discharge specific capacity and coulombic efficiency of the titanium dioxide aerogel reinforced composite polymer electrolyte full cell. DETAILED DESCRIPTION
[0021] The technical content of the present application will become more apparent and easier to understand through the following description of the drawings accompanying the specification. The present application can be embodied in many different forms and the scope of protection of the present application is not limited to the embodiments mentioned herein.
[0022] The main synthesis steps of the titanium dioxide aerogel composite polymer electrolyte provided by the present application are as follows: The present application uses titanium dioxide aerogel as a three-dimensional structure substrate, and a premixed solution of polyaniline (PANI), succinonitrile (SCN) and lithium bisfluorosulfonylimide (LiFSI) with a molar ratio of 6:4:8 is used to fully infiltrate the pore structure of the aerogel under vacuum assistance, and then a cross-linked polyaniline-based electrolyte phase is constructed by initiating a photopolymerization reaction with ultraviolet light. The resulting composite system presents an interpenetrating structure characteristic of a three-dimensional continuous titanium dioxide network and a cross-linked PANI matrix.
[0023] Among the conductive polymers, PANI is relatively popular and has been studied more, because its raw materials are cheap and easy to obtain, the synthesis route is simple, the environmental stability is good, the electrical conductivity is controllable, and there are interesting redox properties related to the nitrogen atoms on the chain. PANI is a polymer based on phenyl groups, both sides of the phenyl ring are provided with -NH- groups. Aniline is easy to undergo oxidative polymerization in the presence of a proton acid. The product generated is a simple 1,4-coupling of monomers. The protonation induces a transition from insulator to conductor, while the number of π electrons in the chain remains unchanged.
[0024] Compared with the separator configuration of the traditional liquid electrolyte, the present application develops a titanium dioxide aerogel phase with a specific topological structure specially for the solid-state polymer electrolyte system. The solidification transformation puts forward more stringent optimization requirements for the structural parameters of the reinforcing agent, which specifically involves the key factors such as the porosity regulation, micro-skeleton configuration and surface chemical modification of the titanium dioxide aerogel. It is worth noting that, thanks to the light weight characteristics of the titanium dioxide aerogel, the cross-linked PANI matrix dominates in the composite material (about 75 wt%), while the total content of the titanium dioxide aerogel skeleton and the residual LiF component of the light curing is controlled within 25 wt%. This component design not only ensures the continuity of the ion transport phase, but also realizes the optimized balance of the ion conductivity through the high volume fraction of the conductive phase, while avoiding the hindering effect of the non-conductive components on the ion migration.
[0025] Compared with some potential inorganic or polymer mechanical reinforcing materials, the titanium dioxide aerogel indeed has many unique characteristics. Its high porosity, ultra-small pore size, large surface area and good surface chemical properties all play an important role in improving the overall performance of the composite electrolyte.
[0026] The following will be described through specific embodiments.
[0027] Example 1
[0028] In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), 0.6 M of polyaniline (PANI), 0.4 M of succinonitrile (SCN) and 0.8 M of lithium bis(fluorosulfonyl)imide (LiFSI) were mixed uniformly, the prepared electrolyte precursor was injected into the aerogel, and 365 nm ultraviolet light was used for 30 minutes of photocuring in an environment of 0.1 MPa, finally forming a cross-linked polymer. 30% of titanium dioxide (TiO2) was added to the obtained cross-linked polymer, and after uniform mixing, a gel-like polymer electrolyte was obtained.
[0029] The conductivity of the polymer electrolyte was tested as follows: The polymer electrolyte prepared in Example 1 was poured into a polytetrafluoroethylene mold or a glass plate, and the solvent was volatilized by natural air drying or heating to form a uniform polymer electrolyte film. The prepared polymer electrolyte film was cut into a suitable size (slightly larger in diameter than a stainless steel disc, but smaller than the inner diameter of a button cell). Then the cut polymer electrolyte film was clamped between two stainless steel electrodes to ensure alignment.
[0030] The electrodes and the film were placed together in a button cell shell, and a sealing machine was used to seal and apply a pressure of 25 MPa. The assembled battery was connected to an electrochemical workstation (frequency range of 1 Hz~10 6 Hz, voltage amplitude of 10 mV). Finally, its conductivity was calculated according to the formula.
[0031] Comparative Example 1
[0032] In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), 0.6 M of polyaniline (PANI), 0.4 M of succinonitrile (SCN) and 0.8 M of lithium bis(fluorosulfonyl)imide (LiFSI) were mixed uniformly, the prepared electrolyte precursor was injected into the aerogel, and 365 nm ultraviolet light was used for 30 minutes of photocuring in an environment of 0.1 MPa, finally forming a cross-linked polymer. 30% of silicon (Si) was added to the obtained cross-linked polymer, and after uniform mixing, a gel-like polymer electrolyte was obtained.
[0033] The conductivity of the polymer electrolyte was tested as follows: The gel-like polymer electrolyte prepared in Comparative Example 1 was poured into a polytetrafluoroethylene mold or a glass plate, and the solvent was volatilized by natural air drying or heating to form a uniform polymer electrolyte film. The prepared polymer electrolyte film was cut into a suitable size (slightly larger in diameter than a stainless steel disc, but smaller than the inner diameter of a button cell). Then the cut polymer electrolyte film was clamped between two stainless steel electrodes to ensure alignment.
[0034] The electrode and the membrane were put together into a coin cell shell, sealed with a crimper and 25 MPa pressure was applied. The assembled battery was connected to an electrochemical workstation (frequency range 1 Hz~10 6 Hz, voltage amplitude 10 mV). Finally, its conductivity was calculated according to the formula.
[0035] Comparative Example 2
[0036] In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), 0.6 M of polyaniline (PANI), 0.4 M of succinonitrile (SCN) and 0.8 M of lithium bisfluorosulfonylimide (LiFSI) were mixed uniformly, and the prepared electrolyte precursor was injected into the aerogel. After vacuum treatment, light curing was performed, and finally a cross-linked polymer was formed. 30% of silicon dioxide (SiO2) was added to the obtained cross-linked polymer, and after uniform mixing, a gel-like polymer electrolyte was obtained.
[0037] The conductivity of the polymer electrolyte was tested as follows: The gel-like polymer electrolyte prepared in Comparative Example 2 was poured into a polytetrafluoroethylene mold or a glass plate, and the solvent was volatilized by natural air drying or heating to form a uniform polymer electrolyte membrane. The prepared polymer electrolyte membrane was cut into a suitable size (slightly larger in diameter than a stainless steel disc, but smaller than the inner diameter of a coin cell). Then the cut polymer electrolyte membrane was clamped between two stainless steel electrodes to ensure alignment.
[0038] The electrode and the membrane were put together into a coin cell shell, sealed with a crimper and 25 MPa pressure was applied. The assembled battery was connected to an electrochemical workstation (frequency range 1 Hz~10 6 Hz, voltage amplitude 10 mV). Finally, its conductivity was calculated according to the formula.
[0039] As a result, the pore and ionic conductivity of the aerogel-type polymer electrolyte prepared in Example 1 and Comparative Examples 1-2 above were as shown in Table 1 below.
[0040] Table 1
[0041] The tensile strength and elongation at break of the aerogel-type polymer electrolyte prepared in Example 1 and Comparative Examples 1-2 above were examined, and the results are shown in Table 2 below.
[0042] Table 2
[0043] As shown in Tables 1 and 2, the ion conductivity of the titanium dioxide aerogel polymer electrolyte prepared by the present application is significantly improved compared with the polymer electrolytes prepared in Comparative Examples 1 and 2, and the elastic modulus of the titanium dioxide aerogel polymer electrolyte is at least one order of magnitude higher than that of the crosslinked PANI-based electrolyte, and the material hardness is obviously enhanced.
[0044] The preferred embodiments of the present application have been described in detail above. It should be understood that modifications and variations can be made by those of ordinary skill in the art without departing from the spirit and scope of the present application. Therefore, the technical solutions obtained by logical analysis, reasoning or limited experiments based on the concept of the present application and the prior art should be within the protection scope defined by the claims.
Claims
1. A method for preparing a titanium dioxide aerogel composite polymer electrolyte having high ionic conductivity, characterized by, The method comprises the following steps: Step 11, configuring a premixed solution of polyaniline PANI, succinonitrile SCN and lithium bisfluorosulfonylimide LiFSI as an electrolyte precursor; Step 12, injecting the electrolyte precursor into the aerogel under vacuum-assisted conditions, and performing photocuring to form a cross-linked polymer; Step 13, adding titanium dioxide to the cross-linked polymer, and uniformly mixing to obtain a titanium dioxide aerogel polymer electrolyte.
2. The production method according to claim 1, characterized by, In step 11, the molar ratio of the polyaniline PANI, succinonitrile SCN and lithium bisfluorosulfonylimide LiFSI is 6:4:
8.
3. The production method according to claim 1, characterized by, In step 11, the electrolyte precursor is configured under inert atmosphere conditions.
4. The method of claim 1, wherein, In step 12, the vacuum condition is 0.1 MPa.
5. The preparation method according to claim 1, characterized in that, In step 12, the photocuring condition is 30 minutes of photocuring under 365 nm ultraviolet light.
6. The method of claim 1, wherein, In step 13, the amount of titanium dioxide added is 30% of the mass fraction of the electrolyte precursor.
7. A titanium dioxide aerogel composite polymer electrolyte prepared by the method of any one of claims 1-6.
8. Use of the titanium dioxide aerogel composite polymer electrolyte of claim 7 in the preparation of a lithium battery.
9. A lithium battery, characterized by A lithium battery containing the titanium dioxide aerogel composite polymer electrolyte of claim 7.
10. The method for preparing a lithium battery as described in claim 9, characterized in that, The method comprises the following steps: Step 101, pouring the titanium dioxide aerogel composite polymer electrolyte into a polytetrafluoroethylene mold or a glass plate, and forming a uniform polymer electrolyte film by natural air drying or heating to volatilize the solvent; Step 102, cutting the prepared polymer electrolyte film into a suitable size; Step 103, clamping the cut polymer electrolyte film between two stainless steel electrodes to ensure alignment; Step 103, placing the stainless steel electrode and the film together into a button cell shell, using a sealing machine to seal and apply pressure, and assembling to form a battery.