78results about How to "Inhibit the "shuttle effect"" patented technology

The invention discloses a composite diaphragm for lithium ion battery for a lithium-sulfur battery and a preparation method and application of the composite diaphragm for lithium ion battery, and belongs to the technical field of electrochemical energy storage. The composite diaphragm of the battery is a three-layer composite diaphragm prepared by respectively coating two sides of a polymer base body with a nano conductive functional coating layer and a ceramic functional coating layer. The nano conductive functional coating layer can accelerate quick transmission of electrons and ions in the battery, and the ceramic functional coating layer can improve the heat stability and the safety of the battery at high temperature, so that the battery prepared based on the composite diaphragm is excellent in electrochemical performance and heat stability. The method is simple in process and liable for industrialization; the prepared composite diaphragm can be widely applied to various lithium ion batteries and lithium-sulfur batteries.

The invention discloses a lithium-sulfur battery cathode material, a preparation method, and a lithium-sulfur battery, and belongs to the technical field of lithium-sulfur battery materials. The lithium-sulfur battery cathode material is a carbon-sulfur composite material, which is coated by a carbon cladding layer with a micro-porous structure. In the preparation method, under a vacuum condition, the raw materials are heated, just in one step, the sulfur and the carbon matrix are uniformly combined, the carbon precursor is carbonized, and the coating on the carbon-sulfur composite material is achieved. Compared with the conventional low-temperature coating method, the carbon cladding layer, which is carbonized at a high temperature and has a micro-porous structure, can form interactions just like the chemical bonds with the carbon-sulfur composite material; so that the micro-porous carbon cladding layer and the carbon-sulfur composite material are tightly combined together, thus the sulfur and discharge products cannot be easily dissolved in the electrolyte, the shuttling effect is prevented, the utilization rate of sulfur is improved, at the same time, the conductivity of the cathode material is better improved, and the cycle stability and capacity retention rate of the lithium-sulfur battery are both improved.

The invention discloses a polymer composite solid electrolyte and a preparation method and application thereof. The polymer composite solid electrolyte is prepared from polyphenylene sulfide, a lithium salt and an organic quinones electron acceptor and is taken as a polymer composite solid electrolyte of a lithium-sulfur battery, the polymer composite solid electrolyte, carbon black and elemental sulfur are fabricated to a composite sulfur electrode material, and thus, a novel lithium-sulfur battery system is formed. The high-molecular polymer composite solid electrolyte provides a relatively good lithium ion migration passage, the lithium ion conductivity of a composite positive electrode material is improved, the high-molecular polymer composite solid electrolyte has certain rigidity and toughness, the volume change of a positive electrode after charge and discharge of the lithium-sulfur battery is buffered, the discharge specific capacity of the lithium-sulfur battery is improved, and the cycle lifetime of the lithium-sulfur battery is prolonged.

The invention belongs to the technical field of lithium-sulfur batteries and in particular relates to a composite membrane of a lithium-sulfur battery. The composite membrane is a negative ion type composite multi-stage porous diaphragm and comprises a mixture of a negative charge ionization polymer and a lithium ion conduction polymer, wherein the composite multi-stage porous diaphragm has a macropore channel structure of 50 nanometers to 2 microns; micropores of 1-50 nanometers are formed in the side walls of macropore channels; the porosity is 50%-80%; macro pores account for 40%-70% of all pores and the rest pores are micropores. The composite multi-stage porous diaphragm provided by the invention has the characteristics and the beneficial effects that the macro pores of the composite membrane are good in electrolyte solution absorption and storage capacity, and the micropores are connected with the macro pores, so that the conduction of lithium ions can be facilitated; polysulfide negative ions can be excluded under the charge effect of the composite membrane material to a certain extent, so that the shuttle effect is inhibited, the loss of active substances is reduced, and the battery efficiency and stability are improved.

The invention belongs to the technical field of lithium-sulfur batteries, and relates to a membrane and for a lithium-sulfur battery. The membrane comprises a membrane body and a covering layer, the covering layer comprises graphene and heterojunction nano materials, the heterojunction nano materials are a symbiotic high adsorption phase-high conductivity phase, the mass ratio of the graphene to the heterojunction nano materials is (3-15):1, and the mass ratio of the high adsorption phase to the high conductivity phase is (1-10): (10-1). Relative to the prior art, according to the membrane, the covering layer is arranged on the membrane, electrochemistry and dynamics performances of the lithium-sulfur battery can be greatly improved, heterojunction nano materials specifically comprise the high adsorption phase and the high conductivity phase, the high adsorption phase has high adsorption action on polysulfide, the high conductivity phase has high conductivity action on the polysulfide, the polysulfide adsorbed by the high adsorption phase can be diffused on the surface of the high conductivity phase, so that transformation of the polysulfide is finished, adsorption and transformation at an interface between the high adsorption phase and the high conductivity phase can be finished, and the 'shuttling effect' of the polysulfide is restrained.

The invention relates to a functional separator for a lithium sulfur battery, and a preparation method and application thereof, belonging to the technical field of electrochemistry. The functional separator of the invention is composed of a polymer separator matrix and a functional modification layer applied one side surface of the polymer separator matrix, wherein the functional modification layer comprises a binder, a conductive carbon material and a dendritic branched macromolecule. The adhesive of the invention has good adhesion and high stability. The conductive carbon material has a veryhigh electron conduction rate, can improve the utilization rate of the active substance and greatly reduce the internal impedance of the battery. The dendritic branch macromolecule contains more organic functional groups, the dendritic branched macromolecule has chemisorption to the polysulfide generated in the sulfur positive electrode region during the cycle, and the carbon material has physical adsorption to the dissolve polysulfide, thereby effectively inhibiting the shuttle effect in the lithium-sulfur battery. Therefore, the lithium sulfur battery prepared using the functional separatordescribed in the present invention exhibits excellent cycle performance and rate performance.

The invention discloses a method for preparing a lithium-sulfur battery cathode material by using bacterial cellulose hydrogel, comprising the following steps of S1, preparing a lithium sulfate/glucose/bacterial cellulose aerogel composite material; and S2, converting the lithium sulfate in the lithium sulfate/glucose/bacterial cellulose aerogel composite material into lithium sulfide, convertingthe glucose into porous carbon, and converting the bacterial cellulose into carbon nanofibers. The method can construct a carbon nanofiber meshed structure, and the lithium sulfide nanoparticles in the structure are coated with the porous carbon, thereby improving the electron transmission efficiency in an electrode, suppressing a shuttling effect, and solving the problem of electrode collapse during lithium-sulfur battery charging and discharging so as to improve the performance of the lithium-sulfur battery.

The invention discloses a sulfur-based cathode composite material and a preparation method thereof. The sulfur-based cathode composite material is represented as (S-R1/MCM-41)R2, in which MCM-41 is a molecular sieve and is a cathode material base body; S is elemental sulfur and is an active constituent; R1 is a conducting polymer, is formed through a synthetic reaction of monomers thereof inside pore channels of the molecular sieve, and serves as a conducting agent and a sulfur-fixing agent; and R2 is a conducting substance, and is coated on the surface of composite material S-R1/MCM-41. The obtained cathode material is charged and discharged under 400 mA.g<-1>, and the first specific discharge capacity is 1390.5 mAh.g<-1> at most; by taking polyaniline as the conducting agent inside the molecular sieve and polypyrrole as the conducting substance, the sulfur-based cathode composite material synthetized by coating outside the material has higher circulation stability performance, the first specific discharge capacity of an assembled battery is 1191.9 mAh.g<-1>, and the capacity retention ratio after 200 times of circulation is 52.17%.

The invention discloses a barrier membrane and a preparation method thereof and a secondary battery comprising the barrier membrane. The barrier membrane comprises one or G layers of single-ion polymer electrolyte membranes, wherein G is greater than or equal to 2; the single-ion polymer electrolyte membranes in the barrier membrane can block electromigration of soluble multi-sulfur anions generated by the secondary battery in the discharge process and block the soluble multi-sulfur anions at one side close to a sulfur positive electrode due to selective through characteristics for cations, so that these multi-sulfur anions are prevented from diffusing to the surface of a negative electrode (for example, a lithium or sodium negative electrode) for reaction; and the problem of reduction of battery capacity and current efficiency of the secondary battery can be solved. In a word, after the barrier membrane is added between the sulfur positive electrode of the secondary battery and a porous membrane, the 'shuttle' effect of polysulfide can be effectively suppressed under the blocking effect of the barrier membrane on the multi-sulfur anions, so that the battery performance of the secondary battery with the sulfur positive electrode can be improved.

The invention relates to a synthesis and preparation method of a composite material applied to a positive intercalation of a lithium-sulphur battery, and in particular relates to a preparation method and application method of a graphene/titanium oxide composite material. The preparation method comprises the following steps of mixing and dissolving titanium oxide and graphene in an organic solvent to form slurry, and coating the surface of a lithium-sulphur positive material with the slurry. The preparation method is simple to operate and low in cost; furthermore, shuttle effects of polysulfide ions in the lithium-sulphur battery can be effectively inhibited; and the capacity and the cycling performance of the battery are greatly increased.

The invention discloses a preparation method for a modified diaphragm for a lithium battery. The preparation method comprises the following steps of S1: performing corona treating or plasma processing on a battery diaphragm; and S2, adding the battery diaphragm processed in the step S1 into a negative ion type polymer solution to be modified to obtain the modified diaphragm for the lithium battery. The modified diaphragm prepared by the invention can effectively suppress pass of negative ions and improve mobility number of positive ions; and particularly in a lithium-sulfur battery, the modified diaphragm can effectively suppress a "flying shuttle effect" generated by the lithium-sulfur battery in a cyclic process, and can suppress capacity attenuation of the lithium-sulfur battery. The modified diaphragm provided by the invention has the advantages of high ionic selectivity, simple preparation process and low economic cost, so that an effective improvement method for development of a high-performance battery (such as a power lithium battery, a lithium-sulfur battery, a lithium cobalt oxide battery, a lithium manganate battery, a lithium phosphate battery and the like) can be provided.

The invention discloses an electrode structure of a lithium sulfur battery and a processing technology therefor. The electrode structure comprises a sulfur-containing active substance layer and a current collector; the upper surface of the active substance layer is coated with a first carbon coating layer; the lower surface of the active substance layer is coated with a second carbon coating layer; and the second carbon coating layer is positioned between the active substance layer and the current collector. The electrode structure has the main characteristics that the two sides of the sulfur-containing active substance layer are coated with the carbon coating layers; namely, the surface of the active substance layer, and the space between the active substance layer and the current collector are coated with the carbon coating layers, wherein a carbon material is taken as the main component, and the carbon material with a large specific surface area or low bulk density is preferable; the carbon material with the relatively large specific surface area can absorb polysulfide and restrain a shuttle effect; meanwhile, the carbon material with the low bulk density can form the relatively loosen carbon coating layer so as to store a large amount of electrolyte in the carbon coating layer, and the dissolution of sulfur and the polysulfide is facilitated, a positive electrode reaction is promoted, and the increase of electrolyte viscosity caused by resolution is restrained.

The invention provides a red phosphorus modified composite separator, and belongs to the technical field of lithium sulfur batteries. The red phosphorus modified composite separator comprises a base diaphragm and a mixed coating carried on one side surface of the base diaphragm; the mixed coating comprises nano red phosphorus particles and conductive carbon; the base diaphragm is one of a PP diaphragm and a PE diaphragm; the mixed coating of the nano red phosphorus particles and the conductive carbon has a thickness of 5 to 30 mum; the mass ratio of the nano red phosphorus particles to the conductive carbon in the mixed coating of the nano red phosphorus particles and the conductive carbon is 0.05-1:1; and the nano red phosphorus particles have a particle diameter of 50 to 100 nm. In the red phosphorus modified composite separator, the nano red phosphorus particles can effectively adsorb polysulfide, so that the shuttle flying effect is well suppressed; the conductive carbon is introduced into the composite separator, which can provide a conductive network for nanoparticles of the nano red phosphorus particles; the polysulfide absorbed via the nano red phosphorus particles is used,thereby improving the utilization rate of sulfur; and the ultra-low cost nano red phosphorus particles are used as raw materials for diaphragm modification, thereby facilitating large-scale preparation.

The invention relates to a stannic oxide/carbonized aerogel core-shell structure composite sulfur electrode material, and a preparation method and application thereof, and belongs to the technical field of lithium-sulfur battery electrode materials. In order to improve the conductivity of a sulfur electrode and solve the poor cycle stability of a lithium-sulfur battery, the electrode material provided by the invention has a shell layer made of stannic oxide and a core layer made of carbonized aerogel microspheres. The monomer sulfur is uniformly dispersed in the carbonized aerogel microsphere,and the mass of sulfur accounts for 60-80% of the total mass of the core-shell structure composite sulfur electrode material. The method improves the conductivity of the sulfur electrode and inhibitsthe volume expansion of sulfur in a reaction process. The stannic oxide shell layer limits the sulfur in the carbonized aerogel core layer to inhibit the leakage of the sulfur, so that the compositesulfur electrode material can maintain good cycle stability during a charge-discharge process. The stannic oxide/carbonized aerogel core-shell structure composite sulfur electrode material provided bythe invention, when applied to the lithium-sulfur battery, can improve the service life and the capacity retention rate of the battery.

The invention provides a nitrogen-phosphorus-doped carbon composite iron phosphide three-dimensional rod-like porous material, a lithium battery diaphragm, a preparation method of the lithium batterydiaphragm, a lithium-sulfur battery and electric equipment. A preparation method of the nitrogen-phosphorus-doped carbon composite iron phosphide three-dimensional rod-like porous material comprises the following steps: mixing raw materials including an iron source, a nitrogen-containing organic matter, phytate and an organic solvent, and drying to obtain a precursor; and carrying out heating treatment on the precursor to obtain the nitrogen-phosphorus-doped carbon composite iron phosphide three-dimensional rod-like porous material for the lithium-sulfur battery diaphragm. The preparation method of the lithium battery diaphragm comprises the following steps: mixing raw materials including the nitrogen-phosphorus doped carbon composite iron phosphide three-dimensional rod-like porous material, a binder and a solvent and dispersing to obtain coating slurry; and coating the surface of a diaphragm base material with the coating slurry to obtain the lithium battery diaphragm. According to the nitrogen-phosphorus-doped carbon composite iron phosphide three-dimensional rod-like porous material, the lithium battery diaphragm, the preparation method of the lithium battery diaphragm and thelithium-sulfur battery, the shuttle effect can be effectively solved, and the electrochemical performance of the lithium-sulfur battery is improved.

The invention belongs to the field of electrochemical materials, and provides a porous carbon sphere packaged vanadium oxide heterogeneous core-shell sphere structure material and a preparation method thereof, a lithium-sulfur battery diaphragm and a lithium-sulfur battery. The preparation method of the porous carbon sphere encapsulated vanadium oxide heterogeneous core-shell sphere structure material comprises the following steps: stirring water, ethanol, ammonia water, tetraethyl orthosilicate, resorcinol and formaldehyde, carrying out a stirring reaction to obtain a carbon-coated silicon dioxide core-shell structure, carbonizing the carbon-coated silicon dioxide core-shell structure, adding the carbon-coated silicon dioxide core-shell structure into a sodium hydroxide solution to obtain a hollow porous carbon sphere, mixing ammonium metavanadate, ethanol and nitric acid to obtain a vanadium oxide solution, adding the hollow porous carbon spheres into the vanadium oxide solution, and carrying out ultrasonic treatment and hydrothermal reaction to obtain a product. According to the invention, the amount of a vanadium oxide precursor entering porous carbon spheres is controlled by adjusting ultrasonic time so as to achieve manual control of a nano structure, and the product takes the non-polar carbon spheres as a surface layer so as to achieve an adsorption effect on polysulfide and show high conversion efficiency when sulfur exists in the inner layer.

The invention discloses a preparation method of a flexible sulfur positive electrode of a lithium-sulfur battery, and belongs to the technical field of lithium-sulfur batteries. The flexible sulfur positive electrode of the lithium-sulfur battery comprises flexible multifunctional carbon foam and a sulfur-containing active substance loaded in the flexible multifunctional carbon foam. The specificpreparation process comprises the steps of preparation of the flexible multifunctional carbon foam, preparation of the flexible sulfur positive electrode of the lithium-sulfur battery and the like. The synthesis method disclosed by the invention is simple and convenient to operate, relatively low in cost and suitable for large-scale production, and has important significance for large-scale production of the lithium-sulfur battery.

The invention discloses a lithium-sulfur battery iron-based biomass carbon intermediate layer, a preparation method thereof and a lithium-sulfur battery. The method comprises the following steps: step 1, cleaning and drying biomass to obtain neutral biomass; step 2, adding the neutral biomass in the step 1 into an iron-containing solution, and drying to obtain iron-based biomass; step 3, calcining the iron-based biomass in the step 2 to obtain iron-based biomass carbon; and step 4, tabletting the iron-based biomass carbon in the step 3 to obtain the iron-based biomass carbon intermediate layer. The biomass carbon-based material used in the invention has relatively good conductivity and adsorption performance, the preparation process is relatively simple, the raw material source is wide, and the middle layer prepared from the biomass carbon-based material has a certain adsorption effect on polysulfide generated in a lithium-sulfur battery due to an oxidation-reduction reaction, can inhibit a shuttle effect, and can effectively improve the cycle performance of the battery.