Potassium ion battery based on high-capacity and high-stability molybdenum sulfide composite electrode and salt-regulated electrolyte
By combining electrospinning technology with salt-controlled electrolyte, the conductivity and structural instability issues of molybdenum disulfide anode materials in potassium-ion batteries were solved, resulting in improved performance of potassium-ion batteries with high capacity and high stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-27
AI Technical Summary
In existing potassium-ion batteries, molybdenum disulfide anode materials have poor conductivity, unstable structure, and poor compatibility with electrolytes, resulting in severe cycle stability and capacity decay.
The microstructure of molybdenum disulfide is precisely controlled by electrospinning technology, and a stable interface layer is constructed on the electrode surface by introducing specific salt additives. Combined with specific salt to regulate the electrolyte, a dense solid electrolyte interface film is formed, which improves the stability of the electrode material and the ionic conductivity of the electrolyte.
The cycling stability and rate performance of molybdenum disulfide composite materials were significantly improved, the initial coulombic efficiency and long-term cycle life of the battery were increased, and the electronic conductivity and ion migration rate of the material were also significantly improved.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of potassium ion batteries, and particularly relates to a potassium ion battery based on a high-capacity and high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte. BACKGROUND
[0002] As a new emerging electrochemical energy storage technology, potassium ion batteries have a broad application prospect in large-scale energy storage due to the advantages of abundant earth's crust reserves, low cost and low standard electrode potential of potassium. However, the large ionic radius of potassium ions will cause significant structural volume change during the process of embedding / extracting electrode materials, resulting in the pulverization of electrode materials and the rapid decay of capacity. Therefore, the development of anode materials with high reversible capacity and excellent structural stability is one of the key challenges to promote the development of potassium ion battery technology.
[0003] Molybdenum disulfide (MoS2) is a typical layered transition metal dichalcogenide, and its wide van der Waals gap between layers is conducive to the reversible embedding and extraction of potassium ions, and is considered as a promising potassium storage anode material. However, the intrinsic electronic conductivity of bulk molybdenum disulfide is low, and it will experience a large volume expansion during charging and discharging, resulting in poor rate performance and poor cycle stability. At present, nanocrystallization and composite with carbon materials (such as electrospun carbon fibers) are often used to improve its electrochemical performance. However, the existing preparation methods still lack accuracy and effectiveness in regulating the microstructure (such as interlayer spacing and nanosheet orientation) of molybdenum disulfide, and at the same time, the compatibility between traditional ester electrolyte and molybdenum disulfide electrode is poor, which is difficult to form a stable solid electrolyte interface film on the electrode surface, further limiting the improvement of its capacity and long cycle life. Improving the stability of the electrode-electrolyte interface is the key to prolonging the cycle life of the battery. A commonly used strategy is to introduce functional film-forming additives. These additive molecules can be preferentially reduced / oxidized on the electrode surface to form a dense and stable solid electrolyte interface film. This SEI film can effectively prevent the continuous decomposition of the electrolyte, thereby significantly reducing the irreversible consumption of active lithium and electrolyte during the cycle process, and ultimately improving the coulombic efficiency and cycle life. However, this strategy faces a serious challenge that the decomposition reaction of some additives itself may not be complete or stable, and continues to proceed in the long-term cycle, which may cause gas side reactions, resulting in an increase in the internal pressure of the battery, volume expansion, and ultimately leading to the failure of the battery. Therefore, the research focus has shifted to the development of new salt additives. The core advantage is that they can promote the formation of a more stable SEI film while significantly reducing the amount of gas generated. This requires the additive to have a proper electrochemical window and decomposition path. SUMMARY
[0004] To solve the above problems, the application designs a synergistic modification strategy. First, the microstructure of molybdenum disulfide is precisely controlled by using electrospinning technology to effectively widen the interlayer spacing, which not only provides a fast ion diffusion channel, but also creates a foundation for surface interface engineering. On this basis, specific salt additives are further introduced to build a highly stable interface layer in the widened interlayer channel and on the material surface using the decomposition products of the salt additives during charging and discharging. This strategy is expected to simultaneously solve the core problems of slow ion transport kinetics in the bulk phase and unstable interfaces, providing a new path for realizing high performance of molybdenum disulfide electrode materials. The technology greatly improves the cycle stability of molybdenum disulfide composite materials in potassium ion batteries.
[0005] The application aims to provide a potassium ion battery based on a high-capacity and high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte to solve the problems of poor conductivity, unstable structure, and poor compatibility with electrolyte of existing molybdenum disulfide negative electrode materials.
[0006] To achieve the above purpose, the application adopts the following technical solutions: A potassium ion battery based on a high-capacity and high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte, characterized in that a molybdenum sulfide composite material is used as a negative electrode. The electrolyte includes a salt-regulated electrolyte and a solvent; the salt-regulated electrolyte includes a main salt and a composite additive; the main salt is potassium hexafluorophosphate, and the composite additive is potassium triflate and potassium bisfluorosulfonylimide.
[0007] Preferably, the solvent is ethylene glycol dimethyl ether. The concentration of potassium hexafluorophosphate in the electrolyte is 0.2-2 mol / L. The molar ratio of potassium triflate to potassium bisfluorosulfonylimide is 1:0.5-2. The molar ratio of the total molar amount of the composite additive to potassium hexafluorophosphate is 0.01-0.1:1.
[0008] Preferably, the molybdenum sulfide composite material is prepared by the following method: (1) Ammonium thiomolybdate and a carbon source are added to a solvent, and continuous stirring is performed until a uniform and viscous spinning solution is formed, and a precursor fiber membrane is obtained by electrospinning; (2) The precursor fiber membrane is pre-oxidized and then carbonized to obtain a molybdenum disulfide / carbon composite fiber material; (3) The composite fiber material, a conductive agent, and a binder are mixed, a solvent is added, and stirring is performed to form a slurry, the slurry is coated on a current collector, and drying, rolling, and punching are performed to obtain a battery negative electrode.
[0009] Preferably, in step (1), the carbon source is at least one of polyacrylonitrile and polypyrrolidone; the solvent is at least one of N,N-dimethylformamide solvent and deionized water; the mass ratio of ammonium thiomolybdate to carbon source is 1:1~5, and the mass ratio of total solid mass to solvent is 1:3~8; the stirring temperature is 50~80℃, and the stirring time is 12~48h; The electrospinning process uses a flat needle, the injection pump has a flow rate of 0.1~1 mL / h, the distance between the syringe needle tip and the receiving device is 10~20 cm, and the working voltage is 10~20 kV. The spinning process is carried out at 20~30℃ and ambient humidity is below 50%.
[0010] Preferably, in step (2), the pre-oxidation conditions are: air atmosphere, processing temperature of 200~400℃, holding time of 1~5h, and heating rate of 2℃ / min; The carbonization conditions are as follows: inert gas atmosphere, first heat to 300~500 ℃ and hold for 1~3 h, then further heat to 700~900 ℃ and hold for 1~3 h, heating rate 2~5 ℃ / min, gas flow rate 50~100 sccm.
[0011] Preferably, in step (3), the conductive agent is one or more of acetylene black, Super P, graphene, and carbon nanotubes; The adhesive is one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate, and polyacrylic acid; the solvent is N-methyl-2-pyrrolidone. The mass ratio of the composite fiber material, conductive agent, and binder is 8:1:1; The coating thickness of the slurry is 50~200μm; the drying conditions are 50~100℃, 12~48h; and the roller pressing pressure is 50~200MPa.
[0012] Preferably, the concentration of potassium hexafluorophosphate in the electrolyte is 1 mol / L; The molar ratio of potassium trifluoromethanesulfonate to potassium difluorosulfonyl imide is 1:1; The total molar amount of the composite additive is in a molar ratio of 0.05:1 to potassium hexafluorophosphate.
[0013] Preferably, in step (1), the mass ratio of ammonium thiomolybdate to carbon source is 1:2, and the mass ratio of total solid mass to solvent is 1:4; In step (2), the pre-oxidation conditions are: a treatment temperature of 300±10℃ and a holding temperature of 2±0.5h; the carbonization conditions are: first, raise the temperature to 400±10℃ and hold for 2±0.5h, and then raise the temperature to 800±10℃ and hold for 2±0.5h.
[0014] Preferably, the potassium-ion battery is a full cell or a half cell.
[0015] Preferably, the electrolyte is prepared in an inert gas environment, wherein the water content and oxygen content are strictly controlled to be below 1 ppm.
[0016] Compared with the prior art, the beneficial effects of the present invention include: (1) This invention successfully constructed a composite structure in which molybdenum disulfide nanosheets and a continuous conductive carbon fiber network are tightly bonded by electrospinning technology and a precisely controlled two-step heat treatment process. This structure not only effectively buffers the volume expansion of molybdenum disulfide during potassium storage and prevents the active material from pulverizing, but also greatly improves the electronic conductivity and ion migration rate of the electrode (from 0.2 mS / cm to 8.5 mS / cm), thereby significantly improving the cycle stability and rate performance of the material. This invention innovatively adopts a composite potassium salt electrolyte system based on ethylene glycol dimethyl ether solvent. Based on this control, the ionic conductivity of the electrolyte is increased from 2.1 mS / cm to 4.3 mS / cm. This electrolyte system can form a stable and dense solid electrolyte interface film on the surface of the molybdenum disulfide / carbon composite material, effectively inhibiting the continuous decomposition of the electrolyte and the occurrence of side reactions, while optimizing the potassium ion desolvation process, which together contributes to the significant improvement of the battery's initial coulombic efficiency and long-term cycle life.
[0017] (2) The method provided by the present invention has clear process parameters and strong repeatability. The prepared molybdenum disulfide / carbon composite material has high specific capacity, high first efficiency and excellent long cycle stability. It provides an efficient and reliable solution to solve the key technical bottleneck of potassium-ion battery anode materials and has the prospect of large-scale industrial application. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.
[0019] Figure 1 This is a scanning electron microscope image of MoS2 / C in Example 1.
[0020] Figure 2 This is a transmission electron microscope (TEM) image of MoS2 / C in Example 1.
[0021] Figure 3 This is an X-ray derivation image of MoS2 / C in Example 1.
[0022] Figure 4The rate performance of MoS2 / C at current densities of 50~1000 mA / g is shown in Example 1.
[0023] Figure 5 The cycling curves of MoS2 / C at a current density of 50 mA / g are shown in Example 1. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0025] A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte is prepared by the following method: 1. Preparation of the electrospinning precursor solution: 0.3 g of ammonium thiomolybdate and 0.6 g of polyacrylonitrile (molecular weight 150,000) were added together to 3.6 g of N,N-dimethylformamide solvent. The mixture was continuously magnetically stirred at 60 °C for 24 hours until a homogeneous and viscous spinning solution was formed. In this embodiment, the mass ratio of ammonium thiomolybdate to carbon source was 1:2, and the mass ratio of total solid mass to solvent was 1:4.
[0026] 2. Preparation of precursor fibers by electrospinning: The above spinning solution was injected into a plastic syringe equipped with a flat-headed stainless steel nozzle. The injection pump was set to a flow rate of 0.2 mL / h. A 16 kV DC high voltage was applied between the nozzle and the roller receiver, with a fixed distance of 15 cm between them. The spinning process was carried out at 26 ℃ and ambient humidity below 50%, ultimately yielding a precursor fiber membrane on the receiver.
[0027] 3. Heat Treatment of Precursor Fibers: The heat treatment is performed in two steps. Step 1: Pre-oxidation: The collected precursor fiber membrane is placed in a muffle furnace and heat-treated in air. The temperature is increased from room temperature to 300 °C at a rate of 2 °C / min and held at this temperature for 2 hours to induce PAN cyclization and cross-linking, thus fixing the fiber morphology. Step 2: Carbonization and Crystallization: The pre-oxidized sample is transferred to a tube furnace and subjected to step heating under argon protection at a flow rate of 50 sccm. First, the temperature is increased to 400 °C at a rate of 2 °C / min and held for 2 hours. Then, the temperature is increased to 800 °C at the same rate and held at this temperature for 2 hours. Finally, it is allowed to cool naturally to room temperature to obtain the final molybdenum disulfide / carbon composite fiber material, denoted as MoS2 / C.
[0028] 4. Electrode Preparation: The obtained MoS2 / C composite material, acetylene black, and polyvinylidene fluoride binder were mixed at a mass ratio of 8:1:1. An appropriate amount of N-methyl-2-pyrrolidone solvent was added, and the mixture was stirred evenly in a planetary mixer to form a slurry. The slurry was uniformly coated onto a copper foil current collector using a blade coating method, controlling the wet film thickness to be approximately 150 μm. Subsequently, the electrode was placed in a vacuum drying oven at 60 ℃ and dried for 24 hours. After removal, it was rolled using a roller press under a pressure of 100 MPa, and finally punched into a circular piece with a diameter of 14 mm as the negative electrode of the battery.
[0029] 5. Electrolyte preparation and battery assembly: The electrolyte was prepared in an argon-filled glove box, with the water and oxygen contents strictly controlled below 1 ppm. Using this electrode as the negative electrode, a glass fiber membrane as the separator, and a potassium metal sheet as the counter electrode, a half-cell was assembled in a CR2032 button cell casing.
[0030] Example 1 The MoS2 / C electrode was prepared and the cell assembled strictly following steps 1 to 5 above. SEM and TEM images of the MoS2 / C electrode are attached. Figure 1 As shown in Figure 2. (Attachment) Figure 3 The corresponding X-ray diffraction pattern is shown. Based on the position of its (002) crystal plane (13.1°), its lattice spacing can be calculated to be 0.675 nm, which is significantly wider than the intrinsic spacing (0.65 nm) of conventional molybdenum disulfide. In the electrolyte prepared in step 5, the electrolyte solvent is ethylene glycol dimethyl ether, the main salt is potassium hexafluorophosphate, and the concentration is 1 mol / L. At the same time, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives, with a molar ratio of 1:1, and the molar ratio of the total salt of the additives to the main salt potassium hexafluorophosphate is 0.05:1.
[0031] According to the method of this embodiment, the electronic conductivity and ion migration rate of the MoS2 / C electrode are increased to 8.5 mS / cm, and the ionic conductivity of the electrolyte is increased to 4.3 mS / cm. The reversible capacities exhibited by MoS2 / C at current densities of 50, 100, 500, and 1000 mA / g are 389, 354, 312, and 255 mAh / g, respectively (see attached figure). Figure 4 After 50 cycles at a current density of 50 mA / g, the reversible specific capacity is 374 mAh / g (see attached diagram). Figure 5 The initial Coulomb efficiency can reach 91%.
[0032] Example 2 The preparation process is basically the same as in Example 1, except that in step 1, the carbon source is replaced with polypyrrolidone; the solvent is replaced with deionized water; the mass ratio of ammonium thiomolybdate to carbon source is 1:4; and the mass ratio of solid content to solvent content is 1:3. In step 2, the spinning solution flow rate is 0.1 mL / h. In the electrolyte prepared in step 5, the electrolyte solvent is ethylene glycol dimethyl ether, the main salt is potassium hexafluorophosphate, and the concentration is 0.6 mol / L. Simultaneously, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives, with a molar ratio of 1:0.5, and the molar ratio of total additive salt to main salt potassium hexafluorophosphate is 0.05:1.
[0033] According to the method of this embodiment, the ionic conductivity of the electrolyte is increased to 4.0 mS / cm, and the reversible specific capacity of the obtained MoS2 / C after 50 cycles at a current density of 50 mA / g under the action of the electrolyte is 354 mAh / g, with an initial coulombic efficiency of 88%.
[0034] Example 3 The preparation process is basically the same as in Example 1, except that in the first pre-oxidation step of step 3, the treatment temperature is 250 ℃ and the holding time is 5 h. In the second step, the highest heat treatment temperature is 700 ℃. In the electrolyte prepared in step 5, the electrolyte solvent is ethylene glycol dimethyl ether, the main salt is potassium hexafluorophosphate, and the concentration is 2 mol / L. At the same time, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives, with a molar ratio of 1:1, and the molar ratio of the total salt of the additives to the main salt potassium hexafluorophosphate is 0.1:1.
[0035] According to the method of this embodiment, the ionic conductivity of the electrolyte can reach 3.8 mS / cm. Based on the synthesis of MoS2 / C materials and electrolyte regulation, the reversible specific capacity after 50 cycles at a current density of 50 mA / g is 366 mAh / g, and the initial coulombic efficiency can reach 87%.
[0036] Example 4 The preparation process is basically the same as in Example 1, except that in step 4, acetylene black is used as the conductive agent; sodium carboxymethyl cellulose is used as the binder; the coating thickness is 200 μm; and the roller pressure is 50 MPa. In salt control, the electrolyte solvent is ethylene glycol dimethyl ether, and the main salt is potassium hexafluorophosphate at a concentration of 1 mol / L. Simultaneously, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives, with a molar ratio of 1:1, and the molar ratio of the total additive salt to the main salt potassium hexafluorophosphate is 0.05:1.
[0037] According to the method of this embodiment, after 50 cycles at a current density of 50 mA / g under the regulation of this electrolyte, the reversible specific capacity of MoS2 / C is 345 mAh / g, and the initial coulombic efficiency can reach 88%.
[0038] Example 5 The preparation process is basically the same as in Example 1, except that in the electrolyte prepared in step 5, the electrolyte solvent is ethylene glycol dimethyl ether, the main salt is potassium hexafluorophosphate, and the concentration is 1 mol / L. Simultaneously, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives, with a molar ratio of 1:2, and the molar ratio of the total additive salt to the main salt potassium hexafluorophosphate is 0.05:1.
[0039] According to the method of this embodiment, after 50 cycles at a current density of 50 mA / g under the regulation of this electrolyte, the reversible specific capacity of MoS2 / C is 334 mAh / g, and the initial coulombic efficiency can reach 85%.
[0040] Comparative Example 1 The preparation process was basically the same as in Example 1, except that the first pre-oxidation process was omitted in step 3, and the precursor fiber was directly heat-treated at 800 °C for 2 hours under argon atmosphere. The lattice spacing of molybdenum disulfide was measured to be 0.65 nm. In the electrolyte prepared in step 5, the electrolyte solvent was ethylene glycol dimethyl ether, the main salt was potassium hexafluorophosphate, and the concentration was 1 mol / L. At the same time, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide were added to the electrolyte as composite additives, with a molar ratio of 1:1, and the molar ratio of the total salt of the additives to the main salt potassium hexafluorophosphate was 0.05:1.
[0041] According to the comparative method, under the regulation of this electrolyte, the reversible specific capacity of MoS2 / C after 50 cycles at a current density of 50 mA / g is 230 mAh / g, and the initial coulombic efficiency can reach 70%.
[0042] Comparative Example 2 The preparation process is basically the same as in Example 1, except that in the electrolyte preparation in step 5, the electrolyte solvent is ethylene glycol dimethyl ether, and the main salt is potassium hexafluorophosphate with a concentration of 1 mol / L. Simultaneously, potassium trifluoromethanesulfonate and potassium difluorosulfonyl imide are added to the electrolyte as composite additives in a molar ratio of 1:1, and the molar ratio of the total additive salt to the main salt potassium hexafluorophosphate is 0.5:1.
[0043] According to the comparative method, under the regulation of this electrolyte, the reversible specific capacity of MoS2 / C after 50 cycles at a current density of 50 mA / g is 238 mAh / g, and the initial coulombic efficiency can reach 75%.
[0044] Comparative Example 3 The preparation process is basically the same as in Example 1, except that: in the electrolyte preparation in step 5, potassium trifluoromethanesulfonate and potassium difluorosulfonylimide composite additives are not added, and only 1 mol / L potassium hexafluorophosphate / ethylene glycol dimethyl ether electrolyte is used.
[0045] According to the comparative method, under the regulation of this electrolyte, the reversible specific capacity of MoS2 / C after 50 cycles at a current density of 50 mA / g is 208 mAh / g, and the initial coulombic efficiency can reach 68%.
[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte, characterized in that, Using molybdenum sulfide composite material as the negative electrode; The electrolyte comprises a salt-regulated electrolyte and a solvent; the salt-regulated electrolyte comprises a main salt and a composite additive; the main salt is potassium hexafluorophosphate, and the composite additive is potassium trifluoromethanesulfonate and potassium difluorosulfonylimide.
2. The potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 1, characterized in that, The solvent is ethylene glycol dimethyl ether; The concentration of potassium hexafluorophosphate in the electrolyte is 0.2~2 mol / L; The molar ratio of potassium trifluoromethanesulfonate to potassium difluorosulfonamide is 1:0.5~2; The total molar amount of the composite additive is in a molar ratio of 0.01 to 0.1 to potassium hexafluorophosphate.
3. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 1, characterized in that, The molybdenum sulfide composite material is prepared by the following method: (1) Add ammonium thiomolybdate and carbon source to the solvent and stir continuously until a uniform and viscous spinning solution is formed. Electrospinning is then used to obtain the precursor fiber membrane. (2) The precursor fiber membrane is pre-oxidized and then carbonized to obtain molybdenum disulfide / carbon composite fiber material. (3) Mix the composite fiber material, conductive agent and binder, add solvent, stir evenly to form a slurry, coat the slurry on the current collector, dry, roll and punch to obtain the battery negative electrode.
4. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 3, characterized in that, In step (1), the carbon source is at least one of polyacrylonitrile and polypyrrolidone; the solvent is at least one of N,N-dimethylformamide solvent and deionized water; the mass ratio of ammonium thiomolybdate to carbon source is 1:1~5, and the mass ratio of total solid mass to solvent is 1:3~8; the stirring temperature is 50~80℃, and the time is 12~48h. The electrospinning process uses a flat needle, the injection pump has a flow rate of 0.1~1 mL / h, the distance between the syringe needle tip and the receiving device is 10~20 cm, and the working voltage is 10~20 kV. The spinning process is carried out at 20~30℃ and ambient humidity is below 50%.
5. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 3, characterized in that, In step (2), The pre-oxidation conditions are: air atmosphere, processing temperature of 200~400℃, holding time of 1~5h, and heating rate of 2℃ / min. The carbonization conditions are as follows: inert gas atmosphere, first heat to 300~500 ℃ and hold for 1~3 h, then further heat to 700~900 ℃ and hold for 1~3 h, heating rate 2~5 ℃ / min, gas flow rate 50~100 sccm.
6. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 3, characterized in that, In step (3), The conductive agent is one or more of acetylene black, Super P, graphene, and carbon nanotubes. The adhesive is one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate, and polyacrylic acid; the solvent is N-methyl-2-pyrrolidone. The mass ratio of the composite fiber material, conductive agent, and binder is 8:1:1; The coating thickness of the slurry is 50~200μm; the drying conditions are 50~100℃, 12~48h; and the roller pressing pressure is 50~200MPa.
7. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to any one of claims 1 to 6, characterized in that, The concentration of potassium hexafluorophosphate in the electrolyte is 1 mol / L; The molar ratio of potassium trifluoromethanesulfonate to potassium difluorosulfonyl imide is 1:1; The total molar amount of the composite additive is in a molar ratio of 0.05:1 to potassium hexafluorophosphate.
8. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 7, characterized in that, In step (1), the mass ratio of ammonium thiomolybdate to carbon source is 1:2, and the mass ratio of total solid mass to solvent is 1:
4. In step (2), the pre-oxidation conditions are: a treatment temperature of 300±10℃ and a holding temperature of 2±0.5h; the carbonization conditions are: first, raise the temperature to 400±10℃ and hold for 2±0.5h, and then raise the temperature to 800±10℃ and hold for 2±0.5h.
9. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 7, characterized in that, The potassium-ion battery is either a full cell or a half cell.
10. A potassium-ion battery based on a high-capacity, high-stability molybdenum sulfide composite electrode and a salt-regulated electrolyte according to claim 7, characterized in that, The electrolyte is prepared in an inert gas environment, wherein the water content and oxygen content are strictly controlled to be below 1 ppm.