790 results about "Polysulfide" patented technology

The present invention belongs to the technical field of desulfurization activated carbon regeneration, and relates to a blast furnace gas desulfurization activated carbon regeneration process and device, the regeneration device includes a washing and extraction tank, a regeneration reactor, a gas detection and analysis system, an automatic control system, a temperature monitoring system, and a deoxygenation reactor; the regeneration process includes S1, washing and extraction, S2, heating regeneration: according to the sulfur content of the outlet gas of the regeneration reactor, the heating temperature is adjusted by gradient, and the temperature range of the regeneration reactor is controlled: 150-300°C, and the temperature gradient is 30-50°C; S3, gas circulation, air oxidation, so that elemental sulfur is precipitated from polysulfide. The regeneration process of the present invention has a small carbon loss rate, increases the number of regenerations, and further reduces costs; the temperature of the thermal regeneration process is 150-300°C, the regeneration temperature is low, and the regeneration temperature can be adjusted according to the outlet gas concentration gradient, reducing energy consumption, and at the same time ammonia resources can be recycled, reducing the amount of solution used and the amount of waste liquid discharged, and the regeneration process can obtain elemental sulfur with economic value.

The invention provides a lithium-sulfur battery abnormal heating diagnosis method and system based on deep learning, and belongs to the technical field of lithium-sulfur battery safety monitoring. According to the method, an enhanced temperature difference sequence is constructed based on temperature and voltage detection data, a temperature state sequence is modeled, and continuous dynamic representation of thermal behaviors is realized; a double-path gating mechanism is designed, a global temperature rise suppression gate is utilized to capture the overall temperature rise trend, and an abnormal temperature rise sensitive gate is combined to focus local violent fluctuation, so that normal charging and discharging temperature rise interference is effectively suppressed, and temperature abnormal probability distribution is output; meanwhile, according to the interval where the current SOC is located, a corresponding voltage compensation function is selected, original voltage data are corrected point by point, a double-group long and short time memory network is designed to extract voltage platform drift characteristics, the perception capability of abnormal drift caused by the polysulfide effect is enhanced, and finally a comprehensive risk index is generated. And when the lithium-sulfur battery is under the polysulfide shuttle effect, the battery heating abnormity identification accuracy and robustness are obviously improved.

The invention discloses a sulfur disproportionation-mediated low-temperature high-efficiency low-carbon denitrification and synchronous ammonium recovery method for sewage, belongs to the field of sewage treatment, and aims to solve the problems that an existing autotroph denitrification process cannot adapt to water quality fluctuation and seasonal variation and is poor in engineering applicability. Polyculture denitrification and elemental sulfur disproportionation (SD) are used as an effective enhanced denitrification scheme and are applied to a low-temperature SDAD system of actual sewage. Sulfide and polysulfide generated in situ through elemental sulfur disproportionation reaction and low-concentration sodium acetate under the polyculture condition are used as supplementary electron donors, so that the denitrification rate is remarkably increased. The process of reducing dissimilatory nitrate into ammonium (DNRA) in the SD-MixBNR system is beneficial to emission reduction of greenhouse gases while realizing ammonium recovery. According to the method, the SD-MixBNR system can be promoted to be widely applied to actual engineering projects under the carbon neutralization background, and the stability and adaptability of the SD-MixBNR system in the face of various water quality fluctuations and seasonal changes are enhanced.

The invention is applicable to the technical field of carbon nanotube materials, and provides a cobalt-selenium co-doped carbon nanotube and a preparation method and application thereof, and the preparation method comprises the following steps: adding cobalt nitrate hexahydrate and a carbon nanotube into a methanol solution to obtain a solution A; dissolving 2-methylimidazole in a methanol solution to obtain a solution B; mixing the solution A and the solution B to form a purple precipitate, separating and washing the purple precipitate, and performing vacuum drying to obtain a ZIF-67 (at) CNT precursor; and putting the ZIF-67 (at) CNT precursor and selenium powder into a tubular furnace, raising the furnace temperature and preserving heat under argon flow, and then cooling to room temperature to obtain the Co-CoSe (at) CNT. According to the invention, a diatomic cobalt (Co) and selenium (Se) co-doped carbon nanotube (CNT) material is adopted as a main body material of sulfur, through a synergistic effect, the chemical adsorption capacity of the electrode material is remarkably enhanced, polysulfide is effectively captured, and excellent physical barrier performance is provided, so that the shuttle effect is further inhibited, and the long cycle life of the lithium-sulfur battery is prolonged.

The invention relates to a solid-phase preparation method and application of battery-grade lithium sulfide, and the preparation method comprises the following steps: (1) firstly, adopting industrial-grade lithium carbonate as a raw material, and carrying out pretreatment purification to remove sodium-calcium-magnesium metal ion impurities; (2) carrying out ball-milling mixing on the purified lithium carbonate raw material and sulfur powder, and carrying out low-temperature melting pre-sintering; (3) performing primary high-temperature calcination on the lithium carbonate and sulfur powder mixture under a protective atmosphere to synthesize a lithium sulfide crude product; (4) carrying out secondary high-temperature calcination on the lithium sulfide crude product in a protective atmosphere to remove excessive sulfur impurities and lithium polysulfide impurities so as to obtain purified lithium sulfide; and (5) carrying out ball milling and crushing on the obtained lithium sulfide, and screening to obtain the battery-grade lithium sulfide with different particle sizes. According to the preparation method, a high-temperature solid-phase synthesis method is adopted, and low-temperature melting pre-sintering and high-temperature two-step calcining methods are adopted, so that reaction byproducts are gas and are easy to remove, production and preparation of high-purity battery-grade lithium sulfide can be realized, and the product has excellent electrochemical performance.

The invention discloses a thermal interface material based on elastomer glass and a preparation method thereof. The thermal interface material is prepared from the following raw materials: a diglycidyl ether-terminated liquid polythioether prepolymer, methyl tetrahydrophthalic anhydride, ethylene glycol diglycidyl ether, a catalyst and a heat-conducting filler. According to the invention, the highly vertical orientation of the heat-conducting filler is realized through a process of combining hot pressing and stack welding, and the heat-conducting filler has an extremely high heat conductivity coefficient in the vertical direction. The Rc of the thermal interface material is much lower than that of a commercial thermal interface material adopting a traditional silicon matrix, and the thermal interface material has a spontaneous contact behavior on the surface of the substrate.

The invention discloses a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, a preparation method thereof and a lithium-sulfur battery, and the preparation method comprises the following steps: placing acidified carbon cloth in a mixed solution of cobalt nitrate, nickel nitrate and hexamethylenetetramine for primary hydrothermal reaction to prepare NiCo2O4 (at) CC; the NiCo2O4 (at) CC is placed in a mixed solution of nickel chloride and sodium molybdate, a secondary hydrothermal reaction is carried out, and NiMoO4 (at) NiCo2O4 (at) CC is obtained; according to the preparation method, NiMoO4-coated NiCo2O4-coated CC is subjected to thermal reduction annealing in a mixed atmosphere of hydrogen and argon, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer is prepared, active sites of the three-dimensional heterostructure are increased, the oxidation-reduction reaction efficiency under high sulfur loading capacity is improved, the nano-particle anchored amorphous nanosheets form the multi-interface heterostructure, and the performance of the lithium-sulfur battery is improved. Good chemical adsorptivity and catalytic conversion on polysulfide in the battery are realized, and the cycle life of the battery is prolonged.

The invention relates to a dual-rare earth metal catalytic nano material, a diaphragm and a preparation method and application thereof. The preparation method comprises the following steps: carrying out hydrothermal reaction on an aqueous solution containing a carbon source, a hard template, a graphene oxide dispersion liquid, a nitrogen source, a phosphorus source, cerium salt and neodymium salt; then carrying out centrifugal separation to obtain a precipitate, and generating a precursor containing Ce and Nd rare earth bimetallic modified nitrogen and phosphorus doped graphene coated microspheres; and carrying out chemical etching on the precipitate after heat treatment to obtain the dual-rare earth metal catalytic nano material (HCS-coated NPrGO / CeNd). The HCS-coated NPrGO / CeNd can be used as a modification material of a lithium-sulfur battery diaphragm, not only can catalyze the conversion of polysulfide, but also can inhibit the shuttle effect of the polysulfide, so that the lithium-sulfur battery has relatively high capacity under high-rate charge and discharge, and has relatively low capacity fading rate in a high-rate long-cycle test.

A method of producing a carbonate bonded article includes preparing a reactive mixture having a particulate mineral source and an aqueous source, and reacting the reactive mixture with carbon dioxide to form a mineral matrix including carbonates. The particulate mineral source includes a leachable compound, the leachable compound including one or more elements selected from: As, Ba, Cd, Cr, Co, Cu, F, Hg, Mo, Mn, Ni, Pb, Sb, Se, V, and Zn. The reactive mixture includes a reducing agent, where the reducing agent includes one or more of a sulfide, disulfide, and polysulfide compound that reacts with the particulate mineral source. The pH of the reactive mixture is at least 10.

The invention discloses an MXene composite material as well as a preparation method and application thereof, and belongs to the technical field of composite materials. The MXene composite material provided by the invention comprises an anthraquinone based covalent organic framework and aminated MXene, the anthraquinonyl covalent organic framework is covalently connected to the surface of the aminated MXene. The MXene composite material is obtained through covalent connection of an anthraquinone covalent organic framework and aminated MXene, on one hand, the covalent connection of the covalent organic framework and the MXene can reduce an electron transfer energy barrier, and therefore the utilization rate of redox active groups in the covalent organic framework is increased; on the other hand, MXene can improve the overall conductivity of the material, anthraquinone groups in the anthraquinone covalent organic framework can be combined through lithium bonds and can be converted into lithium polysulfide, and the MXene composite material is beneficial to preparation of lithium-sulfur batteries with excellent electrochemical performance.

According to the cobalt-doped molybdenum disulfide lithium-sulfur battery composite positive electrode material, the preparation method and the application, a cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene material is prepared by combining a solvothermal method and an annealing technology, and the process is mature; the method is simple, and the composite positive electrode material with high sulfur content is easy to obtain. According to the lithium-sulfur battery composite sulfur positive electrode material disclosed by the invention, the strong chemical adsorption effect and catalytic conversion effect of the cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene carrier on polar lithium polysulfide are utilized, so that the diffusion of the lithium polysulfide in an ether electrolyte is inhibited, and the electrochemical reaction kinetics is improved; therefore, the shuttling effect is slowed down, and the lithium-sulfur battery has the characteristics of high capacity and long service life.

The present invention provides a composite positive electrode for an all-solid-state lithium-sulfur battery and a method for preparing the same, belonging to the technical field of positive electrode materials for lithium-sulfur batteries. The composite positive electrode comprises a sulfur / carbon composite material with a gradient surface modification of phosphorus polysulfide and a solid electrolyte. The composite material comprises porous carbon, sulfur, and phosphorus polysulfide, with the sulfur loaded on the outer surface and / or in the pores of the porous carbon, and a phosphorus polysulfide layer with a gradient distribution of a specific structure on the surface of the sulfur / carbon composite. The present invention utilizes the sulfur / carbon composite material with a gradient surface modification of phosphorus polysulfide as a positive electrode material for an all-solid-state lithium-sulfur battery, effectively increasing the active sulfur content and specific capacity of the composite positive electrode layer. The composite positive electrode of the present invention can have an active sulfur content exceeding 50 wt%, a specific capacity calculated based on elemental sulfur exceeding 1300 mAh / g, and a specific capacity based on the total mass of the composite positive electrode exceeding 650 mAh / g. Furthermore, the composite positive electrode exhibits excellent cycle and rate performance.

The invention discloses a sulfur positive electrode material based on an amorphous crystalline cobalt phosphide / porous carbon composite carrier and a preparation method and application of the sulfur positive electrode material, the amorphous crystalline cobalt phosphide / porous carbon composite carrier is used as a conductive carrier, and the amorphous crystalline cobalt phosphide / porous carbon composite carrier is fused and compounded with active sulfur to obtain the composite sulfur positive electrode material for a lithium-sulfur battery. According to the present invention, the hierarchical porous structure is provided, the high specific surface and the high pore volume provide the sufficient sulfur loading space, the three-dimensional carbon network structure provides the excellent electron conduction and ion diffusion ability, the chemical adsorption can be well achieved, the reversible conversion of the polysulfide can be efficiently catalyzed, and the utilization rate of the active substance can be improved; the catalytic activity can be optimized, the electro-catalytic performance of the catalyst can be improved, dissolution and diffusion of polysulfide can be physically limited, and meanwhile electrode volume expansion in the charging and discharging process is relieved; the sulfur positive electrode material is applied to a lithium-sulfur battery, can effectively inhibit dissolution and shuttling of polysulfide, and shows excellent electrochemical performance.

The invention provides a layered porous WB (at) WO3 heterojunction nanosheet, a preparation method thereof and application of the nanosheet in a lithium-sulfur battery diaphragm, tungsten boron aluminide is etched by using alkali liquor to remove an Al layer in a phase to obtain a two-dimensional layered tungsten boride precursor, and then an in-situ oxidation reaction is performed to generate a WB (at) WO3 heterojunction material. Compared with the prior art, the preparation method disclosed by the invention is simple to operate, green and pollution-free to the environment, good in repeatability and easy to popularize, and the obtained porous layered structure is obtained. The precursor can be directly prepared by stirring, and the WB-coated WO3 heterojunction porous nanosheet is prepared simply and quickly by regulating and controlling the temperature. The method is used for constructing a functional modification layer on the surface of the diaphragm, so that the initial capacity of the lithium-sulfur battery is remarkably improved, the key problem of polysulfide shuttling is effectively solved, and the cycle life of the battery is comprehensively prolonged.

The present invention discloses a highly active cathode material catalyst for lithium-sulfur batteries and a preparation method thereof. The catalyst comprises a flaky nitrogen-doped carbon-based support and platinum metal nanoclusters uniformly embedded on the support surface. The platinum metal nanoclusters are 1-10 nm in size and have a mass ratio of 10-20% on the support. The catalyst is then processed through molten sulfur to serve as the cathode material for lithium-sulfur batteries. The catalyst is prepared by physical mixing a cyanamide compound and an organometallic molybdenum salt, or by adding a defective carbon material, and then directly carbonizing the material in an inert atmosphere in a tube furnace. The high-surface-weight-weight-weight-weight-weight-weight-sheet flaky nitrogen-doped carbon conductive material, with uniform distribution of platinum metal nanoclusters, physically adsorbs and chemically catalyzes polysulfides formed during the charge and discharge process on the positive electrode side of the lithium-sulfur battery, capturing the polysulfides and eliminating the "shuttle effect" during charge and discharge, ultimately improving the electrochemical performance of the electrode material. The initial discharge specific capacity can reach up to 1314.2 mAh / g, and after 100 cycles, the specific capacity decay is only 20%. This catalyst material has broad application prospects for lithium-sulfur batteries.

The invention belongs to the field of nano catalytic materials and lithium-sulfur batteries, and particularly relates to a nitrogen-doped carbon-coated cobalt zinc carbide catalyst material as well as a preparation method and application thereof. The preparation method comprises the following steps: stirring cobalt potassium cyanide, cobalt salt and zinc salt, standing and aging to obtain a precursor, and carbonizing the precursor at high temperature to obtain the catalyst material. The catalyst material comprises cobalt-zinc carbide nanoparticles and an ultrathin nitrogen-carbon structure coating the surfaces of the cobalt-zinc carbide nanoparticles, and the carbon-nitrogen structure can stabilize the internally coated cobalt-zinc carbide nanoparticles and ensure the effective action of lithium polysulfide and cobalt-zinc carbide metal active sites; meanwhile, the catalyst material has a hierarchical porous structure and rich surface active sites, can effectively capture dissolved lithium polysulfide, and can realize efficient catalytic conversion of lithium polysulfide, so that the catalyst material can greatly improve the electrochemical performance of the lithium-sulfur battery as a diaphragm modification functional material of the lithium-sulfur battery.

The invention belongs to the technical field of lithium-sulfur batteries, and particularly relates to a polyurethane-based polymer, a preparation method and application thereof, an electrode binder and a lithium-sulfur battery positive electrode material. The polyurethane-based polymer provided by the invention has a structure as shown in a formula I; in the formula I, R1 comprises alkylene, substituted alkylene, phenyl, substituted phenyl, naphthyl or substituted naphthyl; r2 comprises an ether group, an alkenyl group, an ester group, a phenolic group, an aldehyde group, a wood fiber group or a glycosyl group. The polyurethane-based conductive polymer provided by the invention has abundant chemical adsorption sites, a hydrogen bond network can be formed among molecules, and soluble lithium polysulfide can be effectively anchored and limited on one side of a positive electrode when the polyurethane-based conductive polymer is used as a positive electrode binder, so that the purposes of inhibiting a shuttle effect, stabilizing the battery capacity and improving the cycle performance are achieved. In addition, the polyurethane-based conductive polymer can greatly eliminate the insulativity of a sulfur positive electrode, promote rapid transmission of lithium ions and electrons and improve the specific discharge capacity. # imgabs0 #

The invention discloses a preparation method and application of an in-situ gel polymer electrolyte for a lithium-sulfur battery, and relates to a preparation method and application of a polymer electrolyte. The invention aims to solve the technical problems of rapid capacity attenuation and short cycle life of the existing lithium-sulfur battery. The method comprises the following steps: dissolving a lithium salt in a monomer or a solution formed by mixing the monomer and an ionic liquid, and then adding an initiator for polymerization to obtain the in-situ gel polymer electrolyte. The electrolyte can promote the formation of stable SEI, inhibit the growth of lithium dendrites, improve the ionic conductivity and accelerate the redox rate of positive electrode polysulfide, so that the cycle life of the lithium symmetric battery exceeds 1000h. The reversible specific discharge capacity of a lithium-sulfur battery assembled by using the electrolyte is 1242.0 mAh / g within the range of 1.7-2.8 V and under 0.2 C, the specific discharge capacity after 60 cycles is 953.7 mAh / g, the average coulombic efficiency is 97.5%, and the electrolyte can be used in the field of lithium-sulfur batteries.

The invention relates to the technical field of lithium-sulfur batteries, and discloses a Mo-Mn bimetallic single atomic cluster catalyst, a preparation method and application of the Mo-Mn bimetallic single atomic cluster catalyst in a lithium-sulfur battery diaphragm. The preparation method comprises the following steps: self-assembling and positioning metal ions and organic ligands to form a precursor, sintering an organic material through the cracking operation under a heating condition to obtain a nitrogen-rich carbon carrier, naturally cooling, and successfully synthesizing the Mo-Mn bimetallic single atomic cluster catalyst through characterization methods such as an X-ray diffraction pattern and a transmission electron microscope. And carrying out suction filtration on the obtained target sample to a Celgard diaphragm to prepare the lithium-sulfur battery functional diaphragm. The problem of low utilization rate of active sulfur in lithium-sulfur battery circulation can be effectively improved, and conversion and decomposition of polysulfide are promoted, so that the cycle performance of the lithium-sulfur battery is improved, and guidance is provided for further design and development of novel efficient electro-catalysis of the lithium-sulfur battery.

The invention relates to the field of lithium metal batteries, and provides a lithium metal battery, a manufacturing method thereof and electric equipment, which are at least beneficial to improving the stability of a cathode-free lithium metal battery. The manufacturing method comprises the following steps: carrying out winding treatment or lamination treatment on a positive plate, a negative current collector and a diaphragm, and then putting into a shell to form a battery cell assembly; a first liquid injection process is carried out on the cell assembly, a first electrolyte is injected into the cell assembly, and the first electrolyte comprises the following components: lithium polysulfide, lithium nitrate, lithium salt and the balance of a non-aqueous organic solvent; performing a first formation process on the cell assembly; a second liquid injection process is carried out on the cell assembly, a second electrolyte is injected into the cell assembly, and the second electrolyte comprises fluoroethylene carbonate, a lithium salt, an electrostatic shielding additive, an anchoring filling additive and the balance of a non-aqueous organic solvent; and performing a second formation process on the cell assembly.

The invention discloses a groove wall type sulfur positive electrode material and a preparation method thereof, and relates to the technical field of electrode materials. The reduced graphene oxide aerogel is used as a carrier of active component sulfur, a channel is prepared on the surface of the reduced graphene oxide aerogel based on a picosecond laser processing technology, the groove wall type sulfur positive electrode material is obtained, a unique layered pore wall structure can be realized in an electrode, a greater inhibition effect can be achieved on a shuttle effect of lithium-sulfur battery polysulfide, and the performance of the lithium-sulfur battery is improved. And active substances at the bottoms of the walls can be immersed into the channels along with the electrolyte to be fully utilized. The positive electrode material prepared on the basis of a picosecond laser processing technology has the characteristics of excellent use performance and high stability.

The invention relates to the technical field of lithium-sulfur battery diaphragm materials and preparation thereof, and discloses a preparation method of a lithium-sulfur battery diaphragm modified material, which comprises the following steps: (1) preparing two MOF materials, namely Co-MOF and Mn-MOF, by a solvothermal method; (2) taking the Co-MOF and the Mn-MOF as raw materials, and preparing a CoSe / MnSe-N-C composite material derived from the Co-MOF and the Mn-MOF by utilizing a high-temperature sintering method; and (3) taking a CoSe / MnSe-N-C composite material derived from Co-MOF and Mn-MOF as a modifier, and adopting a coating method to obtain the modified PP diaphragm of the lithium-sulfur battery. According to the lithium-sulfur battery modified PP diaphragm provided by the invention, sulfur-loving sites, lithium-loving sites and catalytic electrode reaction active sites in the modifier CoSe / MnSe-N-C composite material can be utilized to effectively inhibit the shuttle effect of lithium polysulfide and the growth of lithium dendrites, the electrode reaction kinetics of the lithium polysulfide can be accelerated, and the overall electrochemical performance of the lithium-sulfur battery is greatly improved.

The application discloses a high-performance separator coating for lithium battery positive electrodes and a processing method thereof, and belongs to the technical field of lithium battery materials, aiming to solve the problems of weak inhibition of polysulfides, difficult balance between ion transmission and blocking, poor high-temperature stability and low processing efficiency of the existing separator coating. The separator coating is composed of a composite sulfur carrier, a conductive additive, a functional adhesive and a thermal stability enhancer, adopts a double-layer gradient structure with a low-porosity dense barrier in the inner layer and a high-porosity high-efficiency lithium transmission in the outer layer, and its processing method comprises composite sulfur carrier preparation, double-station alternating coating, gradient temperature vacuum drying and low-temperature plasma activation. The application realizes triple synergy of physical adsorption, chemical anchoring and catalytic conversion, so that the capacity retention rate of lithium-sulfur batteries after multiple cycles still reaches a high level, the thermal shrinkage rate of the coating is low, the product qualified rate is improved, and the application is suitable for high-energy-density lithium-sulfur batteries and high-nickel ternary lithium batteries, and meets the long-cycle and high-safety requirements.

The invention relates to the field of lithium-sulfur batteries, and discloses a preparation method of a lithium-sulfur battery electrode modification material, which comprises the following steps: applying a thiophene unit-containing electrolyte additive to a lithium-sulfur battery; and preparing the electrode modification layer of the lithium-sulfur battery through an in-situ electrochemical polymerization reaction. The lithium-sulfur battery electrode modification material provided by the invention is beneficial to promoting conversion of polysulfide and inhibiting the shuttle effect of the polysulfide, and the overall electrochemical performance of the lithium-sulfur battery can be remarkably improved. In addition, the method can also be applied to the fields of sodium-sulfur batteries, potassium-sulfur batteries and other metal-sulfur batteries.

Myriad problems with state of the art lithium based batteries, particularly electrolyte systems thereof, including but not limited to polysulfide shuttling, formation of lithium dendrites and dead lithium during stripping and plating, thermal runaway, volumetric expansion, and strict requirements for electrolyte composition, are well documented in the art and remain major obstacles to realizing the unsurpassed potential for lithium-based batteries as ideal energy storage solutions. The inventive concepts presented herein address said challenges from a multi-pronged approach, revolutionizing the electrolyte system from different approaches to produce synergistic benefits, both within the individual approaches and particularly in combination. The inventive concepts improve electrolyte systems with respect to solvents, electron withdrawing compounds, lithium ion-transporting compounds, performance enhancing additives and chalcogenides. These developments provide benefits including: improved charge / discharge capacity, Coulombic efficiency, cycle life, sulfur optimization, oxidative stability, etc. while reducing polysulfide shuttling and lithium dendrite formation, among other benefits.

The invention discloses a method for preparing electrolytic manganese dioxide from low-grade manganese oxide ore, the electrolytic manganese dioxide and application of the electrolytic manganese dioxide, and belongs to the technical field of battery materials. The method comprises the steps that S1, the low-grade manganese oxide ore is subjected to two-stage countercurrent acid leaching, and a leaching solution is obtained; s2, adjusting the pH value of the leachate, synchronously introducing air, adding a flocculating agent, and settling to remove iron and aluminum; s3, heavy metal is deeply removed, calcium and magnesium are removed through manganese fluoride, and then an oxidizing agent is added for oxygenolysis of polysulfide; s4, anolyte generated in the electrolysis process is added into the purified solution, Mn < 2 + > is subjected to catalytic oxidation through a catalyst, and generated authigenic MnO2 adsorbs residual impurities; and S5, pulse on-off current and periodic reversing are adopted for electrolysis, cathode waste liquid is reused for the leaching procedure in the S1, and electrolytic manganese dioxide is obtained. The electrolytic manganese dioxide with high purity and excellent electrochemical performance is successfully prepared through the specific steps of acid leaching iron removal, heavy metal removal, oxidation reaction, electrolysis and the like.

The present invention discloses a composite carbon nanotube material containing sulfur and carbon nanotubes. The carbon nanotubes are curved or spiral in shape, have transition metal nanoparticles at their ends, and are hollow. The composite carbon nanotube material can be used in lithium-sulfur batteries to mitigate sulfur expansion, promote uniform sulfur distribution, reduce polysulfide shuttling, and improve the capacity, rate capability, and cycle stability of lithium-sulfur batteries.

Exemplary cathode materials include a mixture of an electroactive sulfur material (e.g., S8) and a blended non-sulfur electroactive material comprising two or more non-sulfur electroactive materials, wherein the blended non-sulfur electroactive material is selected such that a discharge voltage profile of the blend of intercalation materials—considered apart from the sulfur electroactive material—has a discharge voltage profile that has substantial overlap with the discharge voltage profile of the sulfur electroactive material. For example, in typical ether electrolytes commonly used in sulfur batteries the discharge voltage profile of S8-Li2S conversion has multiple plateaus (e.g., two plateaus) due to the multistep conversion of sulfur to soluble / intermediate polysulfides (PS) followed by progression to solid or quasi-solid products (e.g., Li2S2 / Li2S). By matching this discharge profile with a provided blend of non-sulfur electroactive materials, the rate and efficiency characteristics of the sulfur cathode can be improved throughout the battery discharge process.

The application discloses a modified polyvinylidene fluoride lithium-sulfur battery positive electrode binder and a preparation method thereof, and belongs to the technical field of lithium-sulfur batteries. In the method, a modifier is connected to a polyvinylidene fluoride molecular chain through hydrogen bonds, cross-linking of the polyvinylidene fluoride molecular chain is realized, and the mechanical property of the polyvinylidene fluoride binder is improved. The introduction of the modifier reduces the crystallinity of the polyvinylidene fluoride, increases the porosity, promotes the swelling of the polyvinylidene fluoride binder in electrolyte, and increases the lithium ion conductivity. Meanwhile, the metallocycle connected to the iron atom in the modifier not only provides an adsorption site for lithium polysulfide, but also promotes the conversion of the lithium polysulfide. The modified polyvinylidene fluoride binder obtained by the method has the advantages of simple synthesis process and low cost, can significantly reduce sulfur positive electrode polarization when applied in a lithium-sulfur battery positive electrode, improves the cycle stability and rate performance of the battery, is suitable for traditional lithium battery electrode preparation processes, and is suitable for large-scale commercial application.