High-entropy multi-site synergistically doped super-stable state solid electrolyte and preparation method thereof
By using sulfide solid electrolytes with high entropy and multi-site synergistic doping, the problem of easy degradation of sulfide electrolytes in air is solved, achieving a balance between high stability and high conductivity, which is suitable for all-solid-state batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-13
- Publication Date
- 2026-03-27
AI Technical Summary
Existing sulfide solid electrolytes cannot effectively resist the synergistic degradation of CO2 and H2O, making it difficult to balance stability and conductivity. Their performance is irreversible, and they are prone to structural collapse and reduced ion conduction efficiency in air.
By employing a high-entropy multi-site synergistic doping method, different ions are doped at the A, B, and X sites, combined with interface self-passivation and trace Li-site modulation, an electrolyte structure of Li6+xMaS5-zOzXw is formed, which inhibits CO2 synergistic degradation and improves conductivity and stability.
It achieves a balance between high stability and high conductivity in air, suppresses the synergistic degradation of CO2 and H2O, and has excellent reversibility of electrolyte structure and ion transport performance, making it suitable for all-solid-state batteries.
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Figure CN121748501A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid-state battery technology, and more specifically, to a high-entropy multi-site synergistic doping ultrastable solid electrolyte and its preparation method. Background Technology
[0002] Against the backdrop of rapid iteration in the new energy industry, solid-state batteries have become a focus of attention in the energy storage field due to their core advantages such as high safety performance, ultra-long cycle life, and high energy density. Among the key components of solid-state batteries, sulfide solid electrolytes are particularly noteworthy for their high ion conductivity (up to 1×10⁻⁶ at room temperature). -3 ~1×10 -2 With advantages such as high S / cm, good compatibility with lithium metal anodes, suitable electrochemical window, and low grain boundary resistance after cold pressing, this material has good application prospects.
[0003] To date, many sulfide solid electrolytes with ionic conductivity comparable to liquid electrolytes at room temperature have been synthesized. For example, Li... 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li7P3S 11 Lithium sulfide of the crystalline silver-germanium type 6.6 P 0.4 Ge 0.6 S5I, Li 5.3 PS 4.3 ClBr 0.7 And Li 6.8 Si 0.8 As 0.2 S5I, etc. However, the air instability of sulfide solid electrolytes severely limits their application. Thermodynamic studies have shown that when exposed to an environment containing H2O, the S in the electrolyte... 2- In a thermodynamically metastable state, it readily undergoes a proton exchange reaction with H₂O to produce highly toxic H₂S gas. This reaction not only releases toxic gases posing safety hazards but also leads to the loss of sulfur atoms in the electrolyte lattice, causing the lattice structure to collapse and directly manifesting as a sharp drop in ionic conductivity. More importantly, the ubiquitous CO₂ in the environment significantly accelerates this hydrolysis process (i.e., the "CO₂ synergistic degradation effect"): CO₂ reacts with H₂O to first form H₂CO₃, which then reacts with S… 2- The reaction produces CO3 2- This not only consumes the active components of the electrolyte but also generates an insulating Li2CO3 interface layer, significantly increasing the resistance to lithium-ion migration and further deteriorating battery performance.
[0004] Existing technologies mostly rely on single doping (such as O) 2- Replace S 2- F - Surface passivation or simple composites (such as oxide coatings) can optimize stability, but these methods have the following limitations:
[0005] (1) Single function: It only addresses a single problem of "hydrolysis" or "oxidation" and cannot cope with the synergistic effect of CO2 and H2O. For example, traditional O2... 2- While doping can suppress hydrolysis to some extent, its effect on CO2-induced carbonation is limited; while F - Surface passivation can only delay surface degradation, but cannot prevent chemical erosion of deep structures.
[0006] (2) The contradiction between stability and conductivity: Although excessive doping improves stability, it easily leads to lattice distortion and Li + Transport channel blockage leads to a sacrifice in conductivity. Density functional theory (DFT) calculations show that when the doping concentration exceeds a critical value, Li... + The migration barrier will be significantly increased, causing the ion conduction efficiency to decrease by an order of magnitude.
[0007] (3) Irreversible performance: Once the electrolyte is hydrolyzed, its initial performance cannot be restored by simple treatment, making it difficult to meet the needs of industrial production and storage. In the failed electrolyte system, the Li2CO3 and H2S products formed will cause permanent structural damage.
[0008] Therefore, developing a sulfide electrolyte that can suppress CO2 synergistic degradation from the material's intrinsic properties while also maintaining high conductivity and reversible performance has become a pressing technical problem to be solved in this field. Summary of the Invention
[0009] The main objective of this invention is to overcome the shortcomings of existing sulfide solid electrolytes, such as their inability to resist the synergistic degradation of CO2 and H2O, the difficulty in balancing stability and conductivity, and irreversible performance. This invention provides a sulfide solid electrolyte based on high-entropy multi-site synergistic doping—achieving four functions: intrinsic resistance to hydrolysis, resistance to CO2 synergistic degradation, high conductivity, and low-temperature reversibility, through "multi-site high-entropy doping + interface self-passivation + performance reversible design." Based on this, a high-entropy multi-site synergistic doped ultrastable solid electrolyte is provided.
[0010] Another objective of this invention is to provide a method for preparing the electrolyte that meets the requirements for the industrialization of all-solid-state batteries.
[0011] Another object of the present invention is to provide an application of the electrolyte.
[0012] To achieve the above objectives, the specific technical solution adopted by the present invention is as follows:
[0013] The present invention discloses a high-entropy, multi-site synergistic doped ultrastable solid electrolyte:
[0014] Compared to those containing P 5+ (Phosphate ion) system, with As 5+ (arsenic ions), Sn 4+ (tin ions), Sb 5+ Sulfide solid electrolytes with antimony ions as central cations exhibit higher intrinsic air stability. These solid electrolyte materials use a non-P-based matrix and employ high-entropy co-doping at multiple sites: A-site (central cation site), B-site (anion S-site), X-site (halogen site), and Li-site. Their chemical formula is: Li 6+x M a S 5-z O z X w ,in:
[0015] (1) M a The high-entropy doped element cluster representing the A site, serving as the core of the electrolyte's cation framework, must contain Ge. 4+ Sn 4+ Sb 5+ As 5+ The mixture contains at least three IV or V cations, and the molar percentage of each cation must meet the "high entropy effect threshold"—the percentage of any single cation should not exceed 50%, and the total percentage of the two cations should not exceed 80%, in order to ensure that the configuration entropy S_config≥1.1 R (R is the gas constant, 8.314 J / (mol·K)).
[0016] From the perspective of ion compatibility, Ge 4+ (Ionic radius 53.5 pm), Sn 4+ (69 pm), Sb 5+ (60 pm), As 5+ The radius difference of (58pm) is less than 15%, which can avoid lattice distortion caused by A-site doping; from the perspective of stability enhancement, Sb 5+ As 5+ The high electronegativity of Sb (2.05, 2.18) can enhance M. a The polarity and bond energy of the -S bond reduce the S... 2- With H in H2O + The reactivity of Sn, while 4+ The introduction of can be achieved through d orbitals and S 2−The π bond effect enhances the overall rigidity of the crystal lattice and suppresses the collapse of the framework caused by moisture.
[0017] The electrolyte has a configurational entropy S_config ≥ 1.1 R. This high entropy effect can suppress the aggregation of dopants at A-site and B-site, reduce lattice defects (such as vacancies and dislocations), improve the intrinsic stability of the electrolyte, and simultaneously reduce Li... + Scattering probability during transmission.
[0018] (2) O z The anion doping at the B site is selected from O. 2- (Oxygen ion) / Se 2- At least one substituted part S 2- The doping concentration satisfies 0.05 ≤ z ≤ 0.7;
[0019] O 2- The ionic radius (140 pm) and S 2- (184 pm) similar, and O 2- Its electronegativity (3.44) is higher than that of S. 2- (2.58), substitution can enhance the binding force between the B-site anion and the A-site cation, and reduce S 2- Hydrolysis activity (O) 2- With H + Combined with the generated OH - Easier to communicate with Li + Coordination, rather than the release of H2S gas); Se 2- The introduction of (198 pm) can reduce the Li-N ratio by adjusting the electron cloud density of the B-site anion. + The migration energy barrier in the crystal lattice compensates for O 2- Doping may lead to a loss of ionic conductivity, thus achieving a balance between stability and conductivity.
[0020] (3)X w The halogen doping at the X-position is selected from Cl. - ,Br - 、 or F - At least two of them, and F - The molar percentage must be ≥0.2;
[0021] Halogen ions, as surface and interface modifiers of electrolytes, F - Can be with Li + High-bond-energy Li-F bonds (588 kJ / mol) are formed, and a dense LiF passivation layer is constructed in situ on the electrolyte surface, blocking the diffusion of H2O and CO2 into the bulk phase; Cl - ,Br -Mixed doping can optimize the ionic environment at the X-site through the "size gradient effect," reducing lattice defects caused by halide ion aggregation, while simultaneously assisting Li... + Rapid transport at the interface reduces electrode-electrolyte interface impedance.
[0022] (4) x represents Li + The metering ratio adjustment parameter has a range of 0.15 ≤ x ≤ 1.2, based on M. a The doping ratio of heterovalent ions (e.g., Sb) 5+ Replace Sn 4+ Li will be produced + Empty space, As 3+ Replace Sn 4+ Li needs to be added + To balance the charge), adjust Li by the x value. + Carrier concentration should be adjusted to avoid charge imbalance caused by Sn-site doping and to optimize Li. + Transmission efficiency;
[0023] Furthermore, the Li site is also doped with Zn. 2+ or Mg 2+ Or Al 3+ or Ga 3+ At least one trace cation, with a molar percentage of 0.02% to 0.6%. Its mechanism of action is as follows:
[0024] CO2 readily reacts with Li in electrolytes in humid environments. + S 2- The reaction produces Li₂CO₃, which has high solubility and readily migrates in the crystal lattice, reacting with M at the A site. a Combine, destroy M a -S Skeleton structure. Introduced Zn 2+ Mg 2+ Al 3+ Ga 3+ Both are hard acid cations, and react with hard bases such as CO3. 2- The binding energy is significantly higher than that of Li. + It can preferentially interact with CO3 2- This forms stable carbonates with low solubility (such as LiAl(CO3)2). These carbonates are immobilized in the bulk electrolyte phase as nanoparticles and cannot migrate to M. a -S skeleton, thus avoiding CO3 2− The disruption of the cationic framework blocks the "CO2-moisture" co-degradation pathway.
[0025] This invention also provides a method for preparing the above-mentioned sulfide solid electrolyte material:
[0026] To address the compositional characteristics of the aforementioned high-entropy multi-site synergistic doped sulfide solid electrolyte, and to avoid excessive oxidation of raw materials, introduction of impurities, and lattice defects during preparation, this invention employs a three-step method: "low-temperature ball milling - segmented sintering - in-situ passivation." The specific steps are as follows:
[0027] S1 Raw Material Pretreatment
[0028] (1) Raw material selection and purity control: Select Li2S, GeS2, SnS2, Sb2S5, As2S5, Li2O, Li2Se, LiCl, LiBr, LiF and trace dopants (ZnS, MgS, Al2S3, Ga2S3) according to the chemical formula stoichiometry; all raw materials must be stored in a glove box to avoid premature moisture absorption.
[0029] (2) Crushing and sieving: The above raw materials are crushed and sieved respectively to control the particle size of the raw materials to ≤75 μm, so as to ensure the uniformity of subsequent mixing.
[0030] (3) Dehydration pretreatment: Dry the sulfur-containing raw materials such as Li2S, GeS2, and SnS2 after sieving to remove the adsorbed water on the surface of the raw materials; Li2O, LiF and other moisture-absorbing raw materials should be added to the subsequent mixing steps within 1 hour after drying to avoid secondary moisture absorption.
[0031] S2 High-Energy Ball Milling Mixing
[0032] (1) Loading and atmosphere control: The pretreated raw materials are fed into the ball mill jar according to the metering ratio, and anhydrous cyclohexane is added as a dispersant at the same time. The solid-liquid mass ratio is 1:5~1:8.
[0033] (2) Segmented ball milling process: adopting “low temperature premixing - high temperature activation” segmented ball milling: first stage (low temperature premixing): ball mill speed 350~450 rpm, grinding temperature controlled at 25~30℃, grinding time 8~12 h, so that the raw materials are initially mixed and form amorphous precursors;
[0034] Second stage (high temperature activation): Increase the ball milling temperature to 50~60℃, increase the rotation speed to 500~550 rpm, and mill for 10~15 hours to promote M a Ge 4+ Sn 4+ Sb 5+ As 5+ ) and S 2− Pre-alignment reduces lattice distortion during subsequent sintering;
[0035] (3) Precursor drying: After ball milling, cyclohexane is removed by evaporation to obtain dried precursor powder.
[0036] S3 Segmented Sintering and In-situ Passivation
[0037] (1) Low-temperature pre-calcination (lattice reconstruction): Inert mixed gas is introduced, the heating rate is 2~3℃ / min, the temperature is raised to 200~250℃, and held for 6~8 h; this stage mainly realizes Li + Initial occupancy and M a -S Initial formation of the skeleton.
[0038] (2) Medium-temperature sintering (high-entropy doping and passivation layer formation): Continue heating at a rate of 1~2℃ / min to 300~350℃, and hold for 10~12 h; during this stage, M a Ge 4+ Sn 4+ Sb 5+ As 5+ The F in LiF diffuses fully into the crystal lattice, forming a high-entropy solid solution, while the F in LiF... - Migrate to the particle surface, and interact with the surface Li + The reaction generates a LiF passivation layer.
[0039] (3) Low-temperature annealing (stress relief and performance optimization): After sintering, the temperature is reduced to 150-180℃ at a rate of 5-8℃ / min and held for 4-6 h to eliminate residual stress inside the lattice; then it is naturally cooled to room temperature to obtain the target high-entropy multi-site synergistic doped sulfide solid electrolyte; the final product must be sealed and stored in a glove box to avoid exposure to air.
[0040] This invention also provides applications of the above-mentioned solid electrolyte:
[0041] The high-entropy multi-site co-doped silver-germanium ore solid electrolyte was applied to an all-solid-state battery. Combined with the ion conduction characteristics of Sn-based electrolytes, the battery assembly parameters were optimized, specifically:
[0042] The composite electrode is formed by mixing NCM622 cathode material (NCM622 has a lower Ni content than NCM811, resulting in weaker oxidizing properties, which is suitable for the anti-oxidation requirements of Sn-based electrolytes) and Li-In alloy anode material (Li-In alloy can reduce the interfacial reactivity between Li metal and Sn-based electrolytes) at a mass ratio of 3.5:5.5:1 and pressing it under a pressure of 60 MPa (higher pressure can increase the interfacial contact area between Sn-based electrolytes and electrodes, and reduce interfacial impedance).
[0043] The composite electrode and the electrolyte are assembled into a CR2032 all-solid-state battery. The battery is charged and discharged at 25°C and 0.05C~0.1C rate (the initial cycle stability of Sn-based electrolyte is slightly lower than that of As-based electrolyte, and low-rate charge and discharge can extend cycle life). The battery has an initial charge and discharge efficiency of ≥89% and a capacity retention rate of ≥92% after 50 cycles.
[0044] Compared with the prior art, the present invention has the following advantages:
[0045] This invention, through a synergistic design of "multi-site high-entropy doping + interface self-passivation + trace Li-site modulation," has the following significant advantages over existing sulfide solid electrolytes:
[0046] (1) Excellent resistance to synergistic degradation of CO2 and H2O: non-P-based system (As 5+ / Sn 4+ / Sb 5+ (with a central cation) high bond energy M a -S structure, B-position O 2- / Se 2- Doping reduces hydrolysis activity; trace doping at Li sites fixes CO3. 2- The LiF passivation layer formed at the X-site F⁻ blocks diffusion, and these synergistic degradation capabilities improve the air stability of the sulfide solid electrolyte.
[0047] (2) Achieving a balance between stability and conductivity: The high entropy effect suppresses the aggregation of dopants, reduces lattice defects, and lowers the Li⁺ transport and scattering probability. At the same time, B-site doping adjusts the electron cloud density of anions, reducing the Li⁺ concentration. + Migration energy barrier. Thus, air stability is improved while maintaining the ionic conductivity of the sulfide electrolyte. Attached Figure Description
[0048] Figure 1 This is the SEM image of Example 1.
[0049] Figure 2 This is the SEM image of Comparative Example 1. Detailed Implementation
[0050] The present invention will be further explained and described below through specific embodiments. It should be understood that the purpose of the following embodiments is to make the technical solution of the present invention clearer and easier to understand, and does not limit the scope of protection of the claims.
[0051] The present invention will be further described below through specific embodiments.
[0052] Test methods
[0053] To visually observe the beneficial effects of this invention, a unified testing method was adopted, specifically including:
[0054] (1) Ionic conductivity: The sample was pressed into a disc with a diameter of 10 mm and a thickness of 1 mm using an AC impedance meter. Au electrodes were wrapped on both sides and tested at 25 °C (frequency range 1 Hz ~ 1 MHz). The initial ionic conductivity and conductivity retention rate after 24 h were calculated.
[0055] (2) Moisture and CO2 resistance test: The electrolyte disc was placed in a temperature and humidity-CO2 atmosphere chamber with a relative humidity of 50%, a CO2 volume fraction of 10%, and a temperature of 25°C. After being placed for 12 h, 24 h, and 48 h, the disc was removed and the change in conductivity was tested.
[0056] (3) Hydrogen sulfide (H2S) release: Using a gas chromatograph, 0.5g of sample was placed in a closed environment at 25℃ and relative humidity of 40%~85% for 24h, and the concentration of released H2S was detected. The amount of H2S released per unit mass of sample was calculated.
[0057] (4) Battery performance: CR2032 all-solid-state batteries were assembled under pressure of 60 MPa using solid electrolyte. Charge and discharge tests were conducted at 25℃ and 0.1C rate (voltage range 2.8~4.3 V), and the first charge and discharge efficiency and cycle capacity retention were recorded.
[0058] Examples and Comparative Examples:
[0059] Example 1: Li 6.3 Ge 0.2 Sn 0.3 Sb 0.3 As 0.2 S 4.5 O 0.5 Cl 0.8 F 0.2 (Al) 3+ (0.2% doping)
[0060] 1. Weighing of raw materials (based on 10g of product):
[0061] (1) Weigh the following in a glove box: Li2S: 1.82g (0.023mol), GeS2: 0.58g (0.003mol), SnS2: 1.05g (0.0045mol), Sb2S5: 1.21g (0.00225mol), As2S5: 0.86g (0.0015mol), Li2O: 0.112g (0.0026mol), LiCl: 0.46g (0.0108mol), LiF: 0.23g (0.0026mol), Al2S3: 0.0042g (0.000027mol);
[0062] 2. Raw material pretreatment:
[0063] (1) Crushing: Grind at 250 rpm for 4 hours in an agate grinding jar. After sieving through a 200-mesh nylon sieve, the particle size distribution is D50=35μm and D90=70μm.
[0064] (2) Dehydration: 135℃, 5×10 -4 After vacuum drying for 9 hours, the moisture content of Li2S was ≤50ppm (measured by Karl Fischer moisture analyzer).
[0065] 3. High-energy ball milling mixing:
[0066] (1) Loading: Add the above raw materials, 100g ZrO2 grinding balls (5mm), and 60g anhydrous cyclohexane (8ppm water content) to a silicon nitride ball mill jar (500mL).
[0067] (2) Segmented ball milling: grind at 380 rpm and 28℃ for 10 h (low temperature premixing); heat up to 55℃ and grind at 520 rpm for 12 h (high temperature activation);
[0068] (3) Drying: 45℃, 2×10 -3 Vacuum rotary evaporation for 8 hours.
[0069] 4. Segmented sintering and in-situ passivation:
[0070] (1) Low-temperature pre-calcination: The precursor powder is spread evenly in a graphite boat, and Ar-H2 (H2 volume fraction 4%) is introduced into a tube furnace. The temperature is increased to 220℃ at 2.5℃ / min and held for 7h.
[0071] (2) Medium-temperature sintering: Heat to 320℃ at a rate of 1.5℃ / min and hold for 11 hours;
[0072] (3) Low temperature annealing: Cool down to 160℃ at 6℃ / min, keep warm for 5h, and cool naturally to room temperature to obtain electrolyte with particle size D50=45μm.
[0073] Examples 2-5 (only key parameters were added; the rest of the preparation methods remained the same as in Example 1)
[0074] Example Chemical formula Li site dopant Configurational entropy 1 <![CDATA[Li 6.3 Ge 0.2 Sn 0.3 Sb 0.3 As 0.2 S 4.5 O 0.5 Cl 0.8 F 0.2 ]]> <![CDATA[Al 3+ (0.2%)]]> 1.25 2 <![CDATA[Li 6.8 Ge 0.1 Sn 0.4 Sb 0.3 As 0.2 S 4.3 O 0.4 Se 0.3 Cl 0.6 F 0.4 ]]> <![CDATA[Ga 3+ (0.4%)]]> 1.18 3 <![CDATA[Li 7.2 Ge 0.3 Sn 0.2 Sb 0.4 As 0.1 S 4.8 Se 0.2 Cl 0.5 Br 0.3 F 0.2 ]]> <![CDATA[Zn 2+ (0.6%)]]> 1.32 4 <![CDATA[Li 6.1 Ge 0.2 Sn 0.3 Sb 0.2 As 0.3 S 4.9 O 0.1 Cl 0.8 F 0.2 ]]> <![CDATA[Mg 2+ (0.02%)]]> 1.21 5 <![CDATA[Li 6.6 Ge 0.1 Sn 0.3 Sb 0.3 As 0.3 S 4.6 O 0.2 Se 0.2 Br 0.7 F 0.3 ]]> <![CDATA[Al 3+ :Here 3+ =1:1(0.3%)]]> 1.28
[0075] Example Key parameters of ball mill Key parameters of sintering final product characteristics 2 Low-temperature premixing: 420 rpm, 30°C, 9 h; High-temperature activation: 550 rpm, 58°C, 13 h Pre-firing: 240℃, 6.5h; Sintering: 340℃, 10h; Annealing: 170℃, 4.5h D50=48μm 3 Low-temperature premixing: 350 rpm, 25°C, 12 h; High-temperature activation: 500 rpm, 52°C, 15 h Preheating: 210℃, 8h; Sintering: 310℃, 12h; Annealing: 150℃, 6h D50=42μm 4 Low-temperature premixing: 400 rpm, 27°C, 8 h; High-temperature activation: 530 rpm, 55°C, 10 h Preheating: 230℃, 6h; Sintering: 300℃, 9h; Annealing: 180℃, 4h D50=40μm 5 Low-temperature premixing: 390 rpm, 29°C, 11 h; High-temperature activation: 540 rpm, 56°C, 14 h Pre-firing: 225℃, 7.5h; Sintering: 330℃, 10.5h; Annealing: 165℃, 5.5h D50=46μm
[0076] Comparative Example 1: Li 10 GeP2S 12
[0077] (1) The raw materials used are Li2S (2.01g), GeS2 (1.74g), and P2S5 (2.25g). The raw materials are weighed in a glove box based on 10g of product.
[0078] (2) Ball milling: agate ball mill jar, ball-to-material ratio 25:1, anhydrous n-hexane as dispersant, grinding at 450 rpm for 20 h;
[0079] (3) Sintering: In a quartz boat, the temperature is increased to 550℃ at 5℃ / min under Ar atmosphere, held for 8h, and then cooled naturally.
[0080] Comparative Example 2: Li6SnS5Cl
[0081] The raw materials used were Li2S (1.78g), SnS2 (2.98g), and LiCl (0.74g). The mixture was ball-milled at 300 rpm for 8 hours and sintered at 300℃ in an Ar atmosphere for 6 hours.
[0082] Comparative Example 3: Li 6.2 Sn 0.8 Sb 0.2 S5Cl
[0083] The raw materials used were Li2S (1.81g), SnS2 (2.38g), Sb2S5 (0.54g), and LiCl (0.77g), and sintered at 320℃ in an Ar atmosphere for 7h.
[0084] Performance Test Results and Analysis
[0085] 1. Room temperature ionic conductivity and kinetic properties
[0086] Serial Number Room temperature ionic conductivity (S / cm) Li⁺ migration number Conductivity at -20℃ (S / cm) Conductivity at 80℃ (S / cm) Electrical conductivity variation range (-20~80℃) Example 1 <![CDATA[3.2×10 -3 ]]> 0.98 <![CDATA[1.0×10 -3 ]]> <![CDATA[3.8×10 -3 ]]> 21.9% Example 2 <![CDATA[5.8×10 -3 ]]> 0.97 <![CDATA[2.1×10 -3 ]]> <![CDATA[6.9×10 -3 ]]> 16.2% Example 3 <![CDATA[4.5×10 -3 ]]> 0.99 <![CDATA[1.5×10 -3 ]]> <![CDATA[5.3×10 -3 ]]> 18.9% Example 4 <![CDATA[1.8×10 -3 ]]> 0.98 <![CDATA[0.5×10 -3 ]]> <![CDATA[2.2×10 -3 ]]> 24.5% Example 5 <![CDATA[4.1×10 -3 ]]> 0.97 <![CDATA[1.4×10 -3 ]]> <![CDATA[5.0×10 -3 ]]> 18.0% Comparative Example 1 <![CDATA[9.5×10 -3 ]]> 0.96 <![CDATA[0.8×10 -3 ]]> <![CDATA[12.1×10 -3 ]]> 93.4% Comparative Example 2 <![CDATA[0.85×10 -3 ]]> 0.95 <![CDATA[0.1×10 -3 ]]> <![CDATA[1.1×10 -3 ]]> 27.3% Comparative Example 3 <![CDATA[1.5×10 -3 ]]> 0.92 <![CDATA[0.3×10 -3 ]]> <![CDATA[1.8×10 -3 ]]> 27.8%
[0087] The following conclusions can be drawn from the analysis of the results of the examples and comparative examples in the table above:
[0088] (1) Example 2: Highest conductivity (5.8 × 10⁻⁶) -3 S / cm), because of B site O 2- / Se 2-Mixed doping (z=0.7) optimized the anion electron cloud density, while the X-site Cl... - / F - Doping (F) - (40%) reduced lattice defects, Li + Lowest migration resistance;
[0089] (2) Example 4: Lowest conductivity (1.8 × 10⁻⁶) -3 S / cm), because of B site O 2- Single-doped (z=0.1) with Mg at the Li site 2+ With a doping amount of only 0.02%, the improvement on the lattice environment is limited, but it is still better than comparative examples 2 and 3.
[0090] (3) Comparative Example 1: Although the conductivity is highest at room temperature, the conductivity drops sharply at low temperature (-20℃) because the rigidity of the PS bond increases at low temperature. + The migration channel shrinks, while the implementation example is due to Sn 4+ The π-bonding effect of the d orbitals results in better lattice flexibility and superior temperature adaptability.
[0091] 2. Moisture and CO2 resistance (performance after 48 hours of testing)
[0092] Serial Number Conductivity retention rate (%) <![CDATA[H2S release amount (mmol / g)]]> Example 1 91 0.025 Example 2 95 0.021 Example 3 89 0.028 Example 4 88 0.030 Example 5 93 0.023 Comparative Example 1 4.2 0.32 Comparative Example 2 35 0.18 Comparative Example 3 52 0.15
[0093] The following conclusions can be drawn from the analysis of the results of the examples and comparative examples in the table above:
[0094] (1) Example 2 has the best corrosion resistance because of the Ga site in Li. 3+ Doping (0.4%) can efficiently fix CO3. 2+ (Forming LiGa(CO3)2), while the surface LiF passivation layer is 8nm thick, blocking H2O / CO2 penetration, and no corrosion products were found after 48h;
[0095] (2) Comparative Example 1 Because P 5+ When it reacts with CO2, its conductivity retention rate is only 4.2%.
[0096] This invention has been described by way of embodiments, but does not constitute a limitation thereof. Other variations of the disclosed embodiments, which are readily apparent to those skilled in the art, should fall within the scope of the claims of this invention, with reference to the description of this invention.
Claims
1. A high-entropy, multi-site synergistic doped ultrastable solid electrolyte, characterized in that: Its chemical formula is: Li 6+X M a S 5-z O z X w ; Among them, Li 6+X For lithium sites; M a For the central cation site; S 5-z O z For anion doping sites; X w For halogen doping sites; The O z For O 2- or Se 2- At least one of them, used to replace part of S 2- The doping concentration is 0.05 ≤ z ≤ 0.7; The x represents Li + The measurement ratio adjustment parameter has a range of 0.15 ≤ x ≤ 1.2; The cation at the central cation site is an IV or V cation with an ionic radius difference of less than 15%, and its configuration entropy satisfies: S_config≥1.1 R, where R is the gas constant, 8.314 J / (mol·K).
2. The high-entropy multi-site synergistic doping ultrastable solid electrolyte according to claim 1, characterized in that: The central cation site includes Ge 4+ Sn 4+ Sb 5+ Or As 5+ At least three of them must be present, and the molar percentage of each cation must meet the following conditions: the percentage of any single cation does not exceed 50%, and the total percentage of the two cations does not exceed 80%, in order to ensure that the configuration entropy meets the high entropy effect threshold condition.
3. The high-entropy multi-site synergistic doping ultrastable solid electrolyte according to claim 2, characterized in that: The central cation site includes Sb 5+ And As 5+ and Ge 4+ or Sn 4+ At least one of them.
4. The high-entropy multi-site synergistic doping ultrastable solid electrolyte according to claim 2, characterized in that: The central cation site includes Sn. 4+ and Ge 4+ Sb 5+ Or As 5+ At least two of them.
5. The high-entropy multi-site synergistic doped ultrastable solid electrolyte according to claim 1, characterized in that: The halogen doping sites include Cl - ,Br - or F - At least two of them, and F - The molar percentage must be ≥0.
2.
6. The high-entropy multi-site synergistic doped ultrastable solid electrolyte according to claim 1, characterized in that: The lithium sites are also doped with Zn. 2+ or Mg 2+ Or Al 3+ or Ga 3+ At least one trace cation, with a molar percentage of 0.02% to 0.6%.
7. A method for preparing a high-entropy multi-site synergistic doped ultrastable solid electrolyte according to any one of claims 1-6, characterized in that: Includes the following steps: S1 Raw Material Pretreatment (1) Raw material selection and purity control: Select Li2S, GeS2, SnS2, Sb2S5, As2S5, Li2O, Li2Se, LiCl, LiBr, LiF and trace dopants (ZnS, MgS, Al2S3, Ga2S3) according to the chemical formula stoichiometry; all raw materials must be stored in a glove box to avoid premature moisture absorption; (2) Crushing and sieving: The above raw materials are crushed and sieved respectively to control the particle size of the raw materials to be ≤75 μm, so as to ensure the uniformity of subsequent mixing; (3) Dehydration pretreatment: Dry the sulfur-containing raw materials such as Li2S, GeS2, and SnS2 after screening to remove the adsorbed water on the surface of the raw materials; S2 ball milling mixture (1) Loading and atmosphere control: The pretreated raw materials are fed into the ball mill jar according to the metering ratio, and anhydrous cyclohexane is added as a dispersant at the same time. The solid-liquid mass ratio is 1:5~1:
8. (2) Segmented ball milling process: The first stage: the ball mill speed is 350~450 rpm, the grinding temperature is controlled at 25~30℃, and the grinding time is 8~12 h, so that the raw materials are initially mixed and form an amorphous precursor. Second stage: Increase the ball milling temperature to 50~60℃, increase the rotation speed to 500~550 rpm, and mill for 10~15 hours to promote M a Cation and S 2- Pre-alignment reduces lattice distortion during subsequent sintering; (3) Precursor drying: After ball milling, cyclohexane is removed by evaporation to obtain dried precursor powder; S3 Segmented Sintering and In-situ Passivation (1) Low-temperature pre-calcination: Inert mixed gas is introduced, the heating rate is 2~3℃ / min, the temperature is raised to 200~250℃, and held for 6~8h; this stage mainly realizes the Li + Initial occupancy and M a -S initial formation of the skeleton; (2) Medium-temperature sintering: Continue to raise the temperature to 300-350℃ at a rate of 1-2℃ / min, and hold for 10-12 h; during this stage, M a The cations diffuse fully into the crystal lattice, forming a high-entropy solid solution, while the F in LiF... - Migrate to the particle surface, and interact with the surface Li + The reaction generates a LiF passivation layer; (3) Low temperature annealing: After sintering, the temperature is reduced to 150-180℃ at a rate of 5-8℃ / min and held for 4-6 h to eliminate residual stress inside the lattice; then it is naturally cooled to room temperature to obtain the target high-entropy multi-site co-doped sulfide solid electrolyte; the final product needs to be sealed and stored in a glove box to avoid exposure to air.
8. The preparation method according to claim 7, characterized in that: In the dehydration pretreatment in S1, the hygroscopic raw materials must be added to the subsequent mixing steps within 1 hour after drying to avoid secondary moisture absorption.
9. An application of a high-entropy multi-site synergistic doped ultrastable solid electrolyte according to any one of claims 1-6, characterized in that: The high-entropy, multi-site co-doped ultrastable solid-state electrolyte is applied to an all-solid-state battery. Combined with the ion conduction characteristics of Sn-based electrolytes, the battery assembly parameters are optimized, specifically: Compared with NCM622 cathode material and Li-In alloy anode material by mass ratio The mixture of 3.5:5.5:1 was pressed under a pressure of 60 MPa to form a composite electrode. The composite electrode was assembled with a highly entropy, multi-site co-doped ultrastable solid electrolyte to form a CR2032 all-solid-state battery.