Polyether-polyester block solid state electrolytes for high voltage lithium batteries and methods of making and batteries thereof

Abstract

This invention discloses a polyether-polyester block solid electrolyte for high-voltage lithium batteries, its preparation method, and the battery itself, belonging to the field of solid electrolyte technology. The electrolyte comprises a polyoxypropylene-polycaprolactone diblock polymer, a lithium salt, an inorganic solid electrolyte, and tris(pentafluorophenyl)borane. This invention provides lithium-ion transport channels through the polyoxypropylene block, provides mechanical support and high-voltage stability through the polycaprolactone block, and, with the synergistic effect of tris(pentafluorophenyl)borane, enables the electrolyte to possess high ionic conductivity, high lithium-ion transport number, a wide electrochemical stability window, and excellent high-voltage cycling performance.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte technology, and in particular to a polyether-polyester block solid electrolyte for high-voltage lithium batteries, its preparation method, and the battery thereof. Background Technology

[0002] With the increasing demands for energy density from electric vehicles and portable electronic devices, the development of high-voltage, high-safety lithium batteries has become a research hotspot. Traditional liquid electrolytes are prone to decomposition at high voltages and pose safety hazards. Solid polymer electrolytes have attracted much attention due to their excellent flexibility, interfacial contact, and safety. However, polyether electrolytes (such as PEO and PDOL) have poor oxidative stability, making them difficult to adapt to high-voltage cathodes above 4.5V; while polyester electrolytes, although possessing high oxidation resistance, have low ionic conductivity. Therefore, there is an urgent need to develop polymer electrolytes that combine high voltage stability and high ionic conductivity. Summary of the Invention

[0003] The main objective of this invention is to provide a polyether-polyester block solid electrolyte for high-voltage lithium batteries and its preparation method, thereby solving the technical problem that solid electrolytes are difficult to balance high voltage stability and high ionic conductivity.

[0004] To achieve the above objectives, the present invention provides a polyether-polyester block solid electrolyte for high-voltage lithium batteries, wherein the polyether-polyester solid electrolyte comprises a polyether-polyester diblock polymer, a lithium salt, an inorganic solid electrolyte, and tris(pentafluorobenzene)borane. The polyether-polyester diblock polymer includes polyether blocks and polyester blocks. The polyether block is selected from polyoxypropylene. The polyester block is selected from polycaprolactone.

[0005] In some embodiments of the present invention, the number-average molecular weight Mn of the block polymer is 10,000 to 30,000.

[0006] In some embodiments of the present invention, the mass ratio of the polyether block to the polyester block is 4:1 to 2:1.

[0007] In some embodiments of the present invention, the number-average molecular weight Mn of the polyether block is 8000~20000.

[0008] In some embodiments of the present invention, the number-average molecular weight Mn of the polyester block is 2000~8000.

[0009] In some embodiments of the present invention, the inorganic solid electrolyte includes one or more of the following: sulfide-based solid electrolyte, NASICON-type solid electrolyte, LISICON-type solid electrolyte, perovskite-type solid electrolyte, or garnet-type solid electrolyte.

[0010] In some embodiments of the present invention, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide.

[0011] The present invention also provides a method for preparing a polyether-polyester block solid electrolyte for high-voltage lithium batteries as described above, comprising the following steps: S10. Disperse the polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte, and tris(pentafluorobenzene)borane into a solvent and stir to obtain a slurry; S20. After the slurry is treated with volatile solvent, it is placed in an atmosphere containing diisocyanate for crosslinking treatment to obtain a crosslinked slurry. S30. The crosslinked slurry is shaped to obtain the polyether-polyester block solid electrolyte of the high-voltage lithium battery.

[0012] In some embodiments of the present invention, the diisocyanate includes at least one of hexamethylene diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate.

[0013] The present invention also provides a battery comprising a polyether-polyester block solid electrolyte of a high-voltage lithium battery as described above.

[0014] The beneficial effects that this invention can achieve are: This invention employs a polyether-polyester diblock polymer, where the polyether block provides a highly efficient lithium-ion transport channel, and the polyester block provides mechanical support and high-voltage resistance. The chemical bonding of the two blocks avoids the phase separation and discontinuous ion channels caused by physical blending, significantly improving the overall ionic conductivity and structural stability of the electrolyte. Furthermore, the interaction between the boron center of tris(pentafluorobenzene)borane and the carbonyl oxygen of the polyester block can further immobilize the anion and regulate the solvation degree of lithium ions, thereby further improving ionic conductivity. Moreover, tris(pentafluorobenzene)borane can form a stable and dense CEI film, effectively inhibiting the oxidative decomposition of the polyether block at high potentials and stabilizing the electrochemical stability of the polyether-polyester composite solid electrolyte. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of a method for preparing a polyether-polyester block solid electrolyte for a high-voltage lithium battery according to the present invention.

[0017] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0021] This invention provides a polyether-polyester block solid electrolyte for high-voltage lithium batteries. The polyether-polyester block solid electrolyte for high-voltage lithium batteries comprises a polyether-polyester diblock polymer, a lithium salt, an inorganic solid electrolyte, and tris(pentafluorobenzene)borane. Polyether-polyester diblock polymers include polyether blocks and polyester blocks. The polyether blocks are selected from polyoxypropylene. The polyester block is selected from polycaprolactone.

[0022] This invention employs a polyether-polyester diblock polymer, where the polyether block provides a highly efficient lithium-ion transport channel, and the polyester block provides mechanical support and high-voltage resistance. The chemical bonding of the two blocks avoids the phase separation and discontinuous ion channels caused by physical blending, significantly improving the overall ionic conductivity and structural stability of the electrolyte. Furthermore, the interaction between the boron center of tris(pentafluorobenzene)borane and the carbonyl oxygen of the polyester block can further immobilize the anion and regulate the solvation degree of lithium ions, thereby further improving ionic conductivity. Moreover, tris(pentafluorobenzene)borane can form a stable and dense CEI film, effectively inhibiting the oxidative decomposition of the polyether block at high potentials and stabilizing the electrochemical stability of the polyether-polyester composite solid electrolyte.

[0023] In this invention, the polyether block of the polyether-polyester diblock polymer is selected from polyoxypropylene, which has excellent lithium-ion coordination and transport capabilities.

[0024] In this invention, the polyester block of the polyether-polyester diblock polymer is selected from polycaprolactone, which has good antioxidant properties, and the ester group can form hydrogen bonds or dipole interactions with lithium salt anions to fix the anions and thereby increase the lithium ion transference number. By selecting different types and molecular weight blocks, the flexibility, crystallinity and ionic conductivity of the electrolyte can be flexibly controlled to adapt to different application scenarios.

[0025] In some embodiments, the number-average molecular weight (Mn) of the block polymer is 10,000 to 30,000. If the total molecular weight is below 10,000, the polymer chains are too short, making it difficult to form stable microphase separation structures (such as vertical cylinders or layered ion channels), and the mechanical strength after film formation is insufficient, making it prone to breakage. If the total molecular weight is above 30,000, the polymer crystallinity is too high, restricting chain segment movement and resulting in a significant decrease in room temperature ionic conductivity. The molecular weight range of 10,000 to 30,000 allows the block polymer to possess both good film-forming properties, flexibility, and suitable crystallinity, ensuring that the polyether-polyester composite solid electrolyte exhibits high ionic conductivity and excellent mechanical properties at room temperature.

[0026] In some embodiments, the mass ratio of polyether blocks to polyester blocks is 4:1 to 2:1. This is beneficial for ensuring that the polyether acts as a continuous matrix to dominate ion transport, forming a highly efficient lithium-ion conduction network. Simultaneously, the polyester blocks are uniformly distributed in the polyether matrix as a dispersed phase, providing reinforcement and shielding. If the polyether ratio is high and the polyester content is too low, it is difficult to effectively suppress the oxidative decomposition of the polyether at high voltages (≥4.5V), and the electrochemical stability window drops below 4.3V. If the polyether ratio is low, the polyester phase may form a continuous structure, blocking ion transport pathways and leading to a decrease in room temperature conductivity. A ratio range of 4:1 to 2:1 achieves both high ionic conductivity and high oxidation potential.

[0027] In some embodiments, the number-average molecular weight (Mn) of the polyether block is 8000–20000. The polyether block is the primary lithium-ion conducting unit, and its molecular weight directly affects chain mobility and crystallization behavior. When the polyether Mn is below 8000, the chains are too short to form continuous ion channels across the electrodes, and the increased compatibility with the polyester block results in insufficient microphase separation driving force, making it difficult to form vertical cylindrical ion channels. When the polyether Mn is above 20000, the crystallinity of the polyether increases significantly, and a large number of lithium ions are trapped in the crystalline regions, unable to participate in conduction, leading to a sharp decrease in room temperature conductivity. The number-average molecular weight range of 8000–20000 allows the polyether block to remain partially amorphous at room temperature, endowing the polymer chains with sufficient mobility while retaining sufficient chain length to assemble ordered ion channels.

[0028] In some embodiments, the number-average molecular weight (Mn) of the polyester blocks is 2000–8000. The polyester blocks provide high-voltage resistance and mechanical support, and their molecular weight determines their crystallinity and the degree of microphase separation from the polyether. When the Mn of the polyester blocks is below 2000, the chain segments are too short to effectively crystallize and form rigid nanoregions, and they are easily miscible with the polyether, disrupting ion channels, and their antioxidant capacity is difficult to match the high-voltage cathode. When the Mn of the polyester blocks is above 8000, the polyester crystallinity is too high, leading to overall electrolyte brittleness, increased interfacial contact resistance, and hindering lithium-ion transport. A molecular weight range of 2000–8000 allows the polyester blocks to form appropriate crystalline microregions, uniformly dispersed in the polyether matrix, which improves oxidation potential and mechanical strength without sacrificing overall ionic conductivity.

[0029] In some embodiments, the preparation method of the polyether-polyester diblock polymer is as follows: using hydroxyl-terminated polyoxypropylene as a macromolecular initiator, the amount of ε-caprolactone is calculated according to the desired mass ratio of polyether blocks to polyester blocks. Dry hydroxyl-terminated polyoxypropylene and ε-caprolactone are added to a reaction flask, and 0.2% of the total molar amount of ε-caprolactone stannous octoate catalyst is added. The reaction is carried out at 130°C for 18 hours under argon protection. After the reaction is complete, the product is dissolved in dichloromethane, precipitated in excess methanol, filtered, and vacuum dried to constant weight to obtain a white solid product, which is the polyether-polyester diblock polymer.

[0030] In some embodiments, the inorganic solid electrolyte includes one or more of the following: sulfide-based solid electrolyte, NASICON-type solid electrolyte, LISICON-type solid electrolyte, perovskite-type solid electrolyte, or garnet-type solid electrolyte.

[0031] In some embodiments, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide.

[0032] This invention also provides a method for preparing a polyether-polyester block solid electrolyte for high-voltage lithium batteries, referring to... Figure 1 This includes the following steps: S10. Disperse the polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte, and tris(pentafluorobenzene)borane into a solvent and stir to obtain a slurry; S20. After the slurry is treated with volatile solvents, it is placed in an atmosphere containing diisocyanate for crosslinking treatment to obtain crosslinked slurry. S30. The cross-linked slurry is shaped to obtain the polyether-polyester block solid electrolyte of the high-voltage lithium battery.

[0033] In some embodiments, the weight ratio of polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte and tris(pentafluorobenzene)borane is (70~90):(2~20):(5~15):(0.5~5).

[0034] In some embodiments, the solvent includes one or more of acetonitrile, acetone, tetrahydrofuran, dichloromethane, or N,N-dimethylformamide.

[0035] In some embodiments, in step S10, the total mass fraction of polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte, and tri(pentafluorobenzene)borane in the slurry is 5% to 20%, and may be further 8% to 15%.

[0036] In some embodiments, the mixing conditions are as follows: under the protection of an inert gas, the mixture is first stirred at a speed of 200 rpm to 400 rpm for 12 h to 24 h, and then ultrasonically dispersed for 30 min to 60 min, in order to improve the uniform dispersion of the inorganic filler and reduce material agglomeration.

[0037] In some embodiments, the inert gas includes at least one of argon and nitrogen.

[0038] In some embodiments, the mixing temperature is 25°C to 50°C.

[0039] In step S20, excess solvent is evaporated to facilitate subsequent crosslinking reaction and shaping treatment. The steps for evaporating the solvent are as follows: natural evaporation in a fume hood at 25℃~28℃ for 12h~48h, or heating on a heating plate at 40℃~60℃ for 6h~12h to reduce excess solvent.

[0040] In some embodiments, the diisocyanate includes at least one of hexamethylene diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate.

[0041] In some embodiments, the slurry is placed in a container, which is then placed in an open bottle containing a crosslinking agent. Heating causes the crosslinking agent to volatilize and react with the slurry to crosslink, thus obtaining a crosslinked slurry.

[0042] In some embodiments, the crosslinking temperature is 40℃~80℃ and the crosslinking time is 6h~12h.

[0043] In some embodiments, the crosslinked slurry can be placed in a mold for shaping.

[0044] In some embodiments, in step S20, the slurry can be placed in a mold, and solvent evaporation treatment can be performed in the mold. The slurry that has undergone solvent evaporation treatment, together with the mold, can be placed in an atmosphere containing diisocyanate for crosslinking treatment to obtain crosslinked slurry, and the shaping treatment in step S30 can be completed simultaneously.

[0045] In some embodiments, the endpoint for solvent evaporation is defined as a solvent residue of 30%-50%.

[0046] The present invention also provides a battery comprising a polyether-polyester block solid electrolyte of a high-voltage lithium battery as described above.

[0047] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0048] The preparation method of the polyether-polyester diblock polymer used in the following examples and comparative examples is as follows: Using hydroxyl-terminated polyoxypropylene as a macromolecular initiator, the amount of ε-caprolactone was calculated according to the desired mass ratio of polyether blocks to polyester blocks. Dry hydroxyl-terminated polyoxypropylene and ε-caprolactone were added to a reaction flask, along with 0.2% of the total molar amount of ε-caprolactone as a stannous octoate catalyst. The reaction was carried out at 130°C for 18 hours under argon protection. After the reaction was completed, the product was dissolved in dichloromethane, precipitated in excess methanol, filtered, and vacuum dried to constant weight to obtain a white solid product, which is the polyether-polyester diblock polymer.

[0049] Example 1 The preparation method of the polyether-polyester block solid electrolyte for high-voltage lithium batteries in Example 1 is as follows: S10: A polyether-polyester diblock polymer, lithium bis(trifluoromethanesulfonyl)imide, an inorganic solid electrolyte, and tri(pentafluorobenzene)borane were dispersed in anhydrous acetonitrile solvent at a weight ratio of 80:11:7:2. The solvent usage was 90 mL of acetonitrile (10% solid content) per 10 g of solid mixture. The mixture was mechanically stirred at 300 rpm for 18 h in an argon glove box, followed by ultrasonic dispersion for 45 min to obtain a homogeneous slurry. The polyether-polyester diblock polymer was a polyoxypropylene-polycaprolactone diblock polymer with a total Mn of 20000, a polyether segment Mn of 15000, a polyester segment Mn of 5000, and a polyether block:polyester block mass ratio of 3:1. The inorganic solid electrolyte was LLZTO.

[0050] S20: Pour the slurry obtained in S10 into a polytetrafluoroethylene mold with an inner size of 10cm×10cm. Evaporate the solvent on a 50℃ heating plate for 4 hours until about 40% of the solvent remains. Then place the mold and slurry into a sealable glass container. Place an open bottle containing 0.3g of hexamethylene diisocyanate (HDI) at the bottom of the container. After sealing, place the container in a 60℃ oven for crosslinking treatment for 8 hours. After removing the container, place it in a fume hood for 1 hour to allow the unreacted crosslinking agent to evaporate, thus obtaining the crosslinked slurry.

[0051] S30: Demold the crosslinked slurry obtained in S20 from the mold and dry it in a vacuum oven at 60°C and a vacuum degree ≤ -0.09MPa for 16 hours to obtain a polyether-polyester block solid electrolyte for high-voltage lithium batteries.

[0052] Example 2 The preparation method of the polyether-polyester block solid electrolyte for high-voltage lithium batteries in Example 2 is as follows: S10: The polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte, and tris(pentafluorobenzene)borane were dispersed in anhydrous acetonitrile solvent at a weight ratio of 75:10:10:5. The solvent volume was 85 mL of acetonitrile (solid content 10.5%) per 10 g of solid mixture. In an argon glove box, the mixture was first mechanically stirred at 300 rpm for 18 h, and then ultrasonically dispersed for 45 min to obtain a homogeneous slurry. The block polymer was a polyoxypropylene-polycaprolactone diblock polymer with a total Mn of 15000, a polyether segment Mn of 10000, a polyester segment Mn of 5000, and a polyether block:polyester block mass ratio of 2:1. The lithium salt was lithium bis(fluorosulfonyl)imide (LiFSI), and the inorganic solid electrolyte was LATP.

[0053] S20 is the same as step S20 in Example 1.

[0054] S30 is the same as step S30 in Example 1.

[0055] Example 3 The preparation method of the polyether-polyester block solid electrolyte for high-voltage lithium batteries in Example 3 is as follows: S10 is the same as step S10 in Example 1.

[0056] S20: Pour the slurry obtained in S10 into a polytetrafluoroethylene mold with an inner size of 10cm×10cm. Evaporate the solvent on a 50℃ heating plate for 4 hours until about 40% of the solvent remains. Then place the mold and slurry into a sealable glass container. Place an open bottle containing 0.25g of toluene diisocyanate (TDI) at the bottom of the container. After sealing, place the container in a 60℃ oven for crosslinking treatment for 10 hours. After removing the container, place it in a fume hood for 1 hour to allow the unreacted crosslinking agent to evaporate, thus obtaining the crosslinked slurry.

[0057] Step S30 is the same as step S30 in Example 1.

[0058] Example 4 The preparation method of the polyether-polyester block solid electrolyte for high-voltage lithium batteries in Example 4 is as follows: S10: A polyether-polyester diblock polymer, lithium bis(trifluoromethanesulfonyl)imide, an inorganic solid electrolyte, and tri(pentafluorobenzene)borane were dispersed in anhydrous acetonitrile solvent at a weight ratio of 85:8:5:2. The solvent usage was 90 mL of acetonitrile per 10 g of solid mixture. The mixture was mechanically stirred at 300 rpm for 18 h in an argon glove box, followed by ultrasonic dispersion for 45 min to obtain a homogeneous slurry. The polyether-polyester diblock polymer was a polyoxypropylene-polycaprolactone diblock polymer with a total Mn of 25000, a polyether segment Mn of 15000, a polyester segment Mn of 10000, and a polyether block:polyester block mass ratio of 1.5:1. The inorganic solid electrolyte was LLZTO.

[0059] S20: Pour the slurry obtained in S10 into a polytetrafluoroethylene mold with an inner size of 10cm×10cm. Evaporate the solvent on a 50℃ heating plate for 4 hours until about 40% of the solvent remains. Then, place the mold and slurry into a sealable glass container. Place an open bottle containing 0.35g of diphenylmethane diisocyanate (MDI) at the bottom of the container. After sealing, place the container in a 60℃ oven for crosslinking treatment for 8 hours. After removing the container, place it in a fume hood for 1 hour to allow the unreacted crosslinking agent to evaporate, thus obtaining the crosslinked slurry.

[0060] S30 is the same as step S30 in Example 1.

[0061] Comparative Example 1 Comparative Example 1 prepared a solid electrolyte according to the method of Example 1, but the difference was that tris(pentafluorobenzene)borane was not added in step S10 of Comparative Example 1.

[0062] Comparative Example 2 Comparative Example 2 prepared a solid electrolyte according to the method of Example 1, except that Comparative Example 2 did not perform the crosslinking treatment in step S20.

[0063] Comparative Example 3 Comparative Example 3 prepared a solid electrolyte according to the method of Example 1, except that tris(pentafluorobenzene)borane was not added in step S10 of Comparative Example 3, and the crosslinking treatment in step S20 was not performed.

[0064] Performance testing Test conditions: All tests were conducted at room temperature (23±2℃) and in a dry environment (dew point ≤-40℃).

[0065] 1. Ionic conductivity test Assemble SS / SS symmetric cells (stainless steel electrode diameter 12mm, area 1.13cm²) 2 An electrochemical workstation was used to perform AC impedance testing (frequency range 0.1Hz~1MHz, amplitude 10mV). The bulk resistance R was read from the intersection of the high-frequency region and the real axis of the Nyquist plot, and the conductivity was calculated using the formula σ= L / (R×S).

[0066] 2. Lithium-ion transference number (t_Li) + )test Assemble a Li / Li symmetric cell (lithium sheet diameter 15mm) using the Bruce-Vincent method: apply a 10mV constant potential polarization, record the initial current I0 and steady-state current I_ss, and perform EIS tests before and after polarization to obtain the interface impedances R0 and R_ss, respectively, according to the formula t_Li + = [I_ss(ΔV - I0R0)] / [I0(ΔV - I_ssR_ss)] calculation.

[0067] 3. Electrochemical stability window testing Assemble a Li / SS half-cell (SS electrode diameter 12 mm) and perform linear scan voltammetry (0~6 V, scan rate 0.5 mV / s) to detect a significant oxidation current (≥0.01 mA / cm²). 2 The potential of ) is taken as the oxidation potential.

[0068] 4. High-voltage full-cell cycle performance test Using LiCoO2 as the positive electrode (LCO:Super-P:PVDF = 8:1:1, loading 3.0 mg / cm³), 2 A CR2032 coin cell was assembled using lithium metal as the negative electrode. The capacity retention was calculated after 200 constant-current charge-discharge cycles at a rate of 0.2C (1C=180mAh / g) within a voltage range of 2.8V to 4.5V.

[0069] The results are shown in Table 1.

[0070] Table 1

[0071] From Table 1, we can see that: The polyether-polyester block solid electrolytes provided in Examples 1 to 4 of this invention achieve excellent comprehensive performance through the synergistic effect of polyoxypropylene-polycaprolactone block copolymer, inorganic solid electrolyte, tris(pentafluorobenzene)borane, and diisocyanate crosslinking treatment. Among them, Example 1 achieves a room temperature conductivity of 21.5 × 10⁻⁶. -5With an S / cm, a lithium-ion transference number of 0.71, an oxidation potential of 5.0V, and a capacity retention rate of 91% after 200 cycles at a high voltage of 4.5V, its performance is significantly better than that of the comparative ratios.

[0072] The conductivity of Comparative Example 1 (without tri(pentafluorobenzene)borane) decreased to 9.6 × 10⁻⁶. -5 The S / cm and capacity retention decreased to 76%, indicating that tris(pentafluorobenzene)borane effectively improved the ion transport efficiency and high voltage stability of the electrolyte by forming a CEI membrane and immobilizing anions.

[0073] The conductivity of Comparative Example 2 (without cross-linking treatment) was 14.2 × 10⁻⁶. -5 The S / cm and capacity retention rate of 83% indicate that cross-linking treatment helps to construct a stable three-dimensional network structure and improves the mechanical strength and cycling stability of the electrolyte.

[0074] Comparative Example 3 (which simultaneously lacks tri(pentafluorobenzene)borane and undergoes cross-linking treatment) exhibits the lowest performance across all categories, with an electrical conductivity of only 5.8 × 10⁻⁶. -5 With a capacity retention rate of only 68%, the S / cm further demonstrates a significant synergistic effect between tris(pentafluorobenzene)borane and crosslinking treatment. The combined presence of the two can produce technical effects far superior to those of a single element.

[0075] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A polyether-polyester block solid electrolyte for high-voltage lithium batteries, characterized in that, The polyether-polyester solid electrolyte comprises a polyether-polyester diblock polymer, a lithium salt, an inorganic solid electrolyte, and tris(pentafluorobenzene)borane. The polyether-polyester diblock polymer includes polyether blocks and polyester blocks. The polyether block is selected from polyoxypropylene. The polyester block is selected from polycaprolactone.

2. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The number-average molecular weight Mn of the block polymer is 10,000 to 30,000.

3. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The mass ratio of the polyether block to the polyester block is 4:1 to 2:

1.

4. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The number-average molecular weight (Mn) of the polyether block is 8000~20000.

5. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The number-average molecular weight Mn of the polyester block is 2000~8000.

6. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The inorganic solid electrolyte includes one or more of the following: sulfide-based solid electrolyte, NASICON-type solid electrolyte, LISICON-type solid electrolyte, perovskite-type solid electrolyte, or garnet-type solid electrolyte.

7. The polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 1, characterized in that, The lithium salt is lithium bis(trifluoromethanesulfonyl)imide.

8. A method for preparing a polyether-polyester block solid electrolyte for high-voltage lithium batteries according to any one of claims 1 to 7, characterized in that, Includes the following steps: S10. Disperse the polyether-polyester diblock polymer, lithium salt, inorganic solid electrolyte, and tris(pentafluorobenzene)borane into a solvent and stir to obtain a slurry; S20. After the slurry is treated with volatile solvent, it is placed in an atmosphere containing diisocyanate for crosslinking treatment to obtain a crosslinked slurry. S30. The crosslinked slurry is shaped to obtain the polyether-polyester block solid electrolyte of the high-voltage lithium battery.

9. The method for preparing a polyether-polyester block solid electrolyte for high-voltage lithium batteries according to claim 8, characterized in that, The diisocyanate includes at least one of hexamethylene diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate.

10. A battery, characterized in that, The battery comprises a polyether-polyester block solid electrolyte of a high-voltage lithium battery as described in any one of claims 1 to 7.

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