297results about How to "Improve the first charge and discharge efficiency" patented technology

The invention discloses a silicon oxide/carbon cathode material of a lithium ion battery and a preparation method of the material. The silicon oxide/carbon cathode material is a three-layer compound material with a core-shell structure and takes a graphite material as an inner core, porous silicon oxide as a middle layer and organic pyrolytic carbon as an outermost covering layer; and the preparation method comprises a process of preparing porous SiOx and a carbon covering process. Compared with the prior art, active metal is added to reduce SiOx partially, the volume expansion effect of silicon particles is greatly reduced as the volume expansion effect of the silicon particles in the charging and discharging processes can be automatically absorbed by the obtained product structure, and the initial charging and discharging efficiency and the cycling stability are remarkably improved. The initial reversible specific capacity is larger than 600 mAh/g, the initial charging and discharging efficiency is higher than 88%, the capacity retention ratio is higher than 98% after the capacity is cycled for 50 times, the synthetic process is simple and easy to operate, the manufacturing cost is low, and the large-scale production is easy to realize.

The invention relates to a synthesis and surface modification method of a lithium rich anode material Li1+xM1-xO2 (M is one or more of Ni, Co and Mn, and X is more than or equal to 0 and less than or equal to 1/3) for a lithium ion battery. The method comprises the following steps of: synthesizing a precursor by using a carbonate precipitation method, mixing the precursor and a lithium salt, and calcining for 2 to 20 hours at the temperature of between 800 and 1,100 EG C to obtain a lithium rich material, wherein the prepared lithium rich material has controllable particle size and higher reversible capacity; and dissolving persulfate or sulfate in an amount which is 5 to 80 mass percent of the lithium rich material into deionized water, adding the lithium rich material, stirring for 2 to 100 hours at the temperature of between 25 and 80 DEG C, heating the materials to the temperature of between 100 and 500 DEG C in a muffle furnace, calcining the materials for 2 to 20 hours, fully filtering the obtained materials, and washing off impurities to obtain the surface modified anode material Li1+x-yM1-xO2. The synthesized lithium rich material has controllable particle size; the first charge/discharge efficiency of the lithium rich material and the discharge specific capacity and the cyclical stability under high magnification can be improved; and the method is simple, low in cost, convenient for operation and suitable for industrialized production.

The invention provides preparation and application of a lithium battery silicon-carbon composite material taking synthetic graphite as a carrier. The preparation method comprises the following steps of: dissolving nanometer silicon and synthetic graphite in a dispersant to obtain a uniform dispersion liquid, adding an organic carbon source, stirring uniformly to obtain a mixed liquid, feeding the mixed liquid into a closed circulation spray dryer to prepare composite precursor powder, pre-sintering for 3-10 hours at the temperature of 300-700 DEG C to obtain a silicon-carbon composite material subjected to primary carbon cladding; and further dissolving the silicon-carbon composite material subjected to primary carbon cladding with the organic carbon source in a dispersant, stirring to obtain a uniform mixed liquid, feeding the uniform mixed liquid into a second closed circulation spray dryer to prepare composite powder, and heating the powder for 6-18 hours at the temperature of 700-1000 DEG C, so as to obtain the lithium battery silicon-carbon composite material taking synthetic graphite as a carrier. The lithium battery silicon-carbon composite material prepared by the invention shows such excellent electrochemical properties as high first charge-discharge efficiency, high specific capacity and good cycle performance after being applied to a lithium battery.

The invention relates to a negative pole piece, which comprises a negative pole current collector and a negative pole film layer, wherein the negative pole film layer is arranged on the negative pole current collector and comprises at least two negative pole active material layers; and the at least two negative pole active material layers are sequentially arranged on the negative pole current collector from the inside to the outside according to the lithium-ion dynamic property decreasing order of the negative pole active material layers. The invention particularly relates to the negative pole film layer of which the negative pole active material is a graphite/hard carbon and/or silicon material composite material. The graphite is compounded with the hard carbon and/or silicon material, and a multi-layer gradient of which the lithium-ion dynamic property is sequentially increased from the outside to the inside is formed, so that the negative pole piece has the effects of simultaneously improving the charging capability and increasing the energy density.

The invention relates to a silicon-carbon composite negative pole material preparation method and a lithium ion battery. The preparation method comprises putting nanometer silicon and graphite micro-powder into a ball mill, carrying out ball milling uniform dispersion in an organic solvent environment, carrying out vacuum drying, putting the dried mixture and asphalt into a cone-type mixer, carrying out coarse mixing, putting the mixed powder subjected to coarse mixing into a mechanical fusion machine, carrying out mechanical fusion, carrying out heat treatment in an inert gas protective atmosphere and carrying out cooling to obtain the silicon-carbon composite negative pole material. The preparation method carries out asphalt softening coating on nanometer silicon so that silicon particle and electrolyte direct contact is avoided, a capacity reduction rate is delayed, a lithium ion diffusion path is shortened, an electrode material electron conduction loss is avoided, and first charge-discharge efficiency, a charge-discharge electric capacity and cycle performances are improved. Before coating, nanometer silicon is dispersed through graphite micro-powder so that it is avoided that in asphalt coating, nanometer silicon aggregation causes local capacity excess and nanometer silicon is uniformly dispersed.

Disclosed is a polycrystal high-nickel positive electrode material used for a lithium ion battery. The polycrystal high-nickel positive electrode material comprises a base material with a layered structure and a coating layer which is arranged outside the base material and has a spinel structure; the general formula of the base material is LiNi<1-x-y>Co<x>M<y>O<2>, wherein M is at least one kind of Mn and Al; the coating layer is lithium manganese oxide; the mass percentage of the total impurity lithium on the surface of the base material is less than 0.085% based on the total mass percentage of the base material; the preparation method for the positive electrode material comprises the following steps of weighing Ni<1-x-y>Co<x>M<y>(OH)<2>, and mixing with a lithium source, then carrying out thermal treatment, cooling, crushing and sieving to obtain the base material; measuring the content of the residual impurity Li<2>CO<3> and LiOH on the surface of the base material, adding into the metal Mn compound according to the measurement result, and carrying out low-temperature thermal treatment in an oxygen atmosphere to obtain the polycrystal high-nickel positive electrode material used for the lithium ion battery. The polycrystal high-nickel positive electrode material provided by the invention has the advantages of low material alkalinity, low inflatable degree, excellent processing property and cycling performance, and the like.

The invention relates to a monox/carbon composite material, comprising monox/graphene particles, organic matter pyrolysis carbon and graphite powder, wherein monox particles are adhered to the surface of a grapheme sheet; the organic matter pyrolysis carbon coats the monox/ graphene particles, and then is compounded with graphite. The preparation method of the monox/carbon composite material comprises the steps of: mixing monox particles with graphene to obtain the monox/graphene particles; coating organic carbon by obtained monox/graphene particles, thereby obtaining the monox/graphene material coated by the organic matter pyrolysis carbon; and mixing the obtained monox/graphene material coated by the organic matter pyrolysis carbon with the graphite powder, so as to obtain the monox/carbon composite material. The monox/carbon composite material is used as a lithium ion battery cathode material. Thus, the monox/carbon composite material has the characteristics of high first charge and discharge efficiency, excellent cycle performance and power charge and discharge properties, and low volume expansion effect.

The invention provides a pre-lithiation treatment process of a silicon-based negative electrode. The pre-lithiation treatment process comprises the steps of paste uniformization, coating, metal lithium electrodeposition by a two-step constant-current pulse deposition method, DMC soaking, drying and the like. The invention simultaneously provides a pre-lithiation treatment device of the silicon-based negative electrode. The pre-lithiation treatment device comprises an electrolytic groove, a working electrode, two pieces of counter electrodes and a wire. With the adoption of the pre-lithiation treatment process and device, the initial charging and discharging efficiency of a silicon-carbon negative electrode can be effectively improved, and the cycle lifetime of the silicon-carbon negative electrode can be prolonged.

The invention provides a quick formation method for a lithium ion battery adapting to various cathode material systems. The formation method is divided into three stages, and in each stage, constant-current charging of the battery is realized through different currents, and the upper-limit cut-off voltage of each stage is controlled as the end condition. Currents selected in each stage gradually increase in a stepped manner, so that an SEI (Solid Electrolyte Interphase) film can be slowly and uniformly produced on the surface of a graphite negative pole; and selected upper-limit cut-off voltages are in different ranges respectively according to different cathode material systems, so that the SEI film can be effectively produced while the excessive lithium ion consumption is avoided. Besides, after each stage finishes, a certain standing time is set, so that the SEI films formed in each stage can be in steady states as far as possible According to the invention, not only is the production efficiency of the formation procedure improved, but also the quality of the SEI films in the formation process is guaranteed, and further, the comprehensive electrochemical performance of the lithium ion battery is improved.

The invention provides a lithium ion secondary cell, in particular a long-life fast-charging cell. The long-life fast-charging cell comprises a positive electrode material, a negative electrode material, a diaphragm and a nonaqueous electrolyte, wherein the active substance of the negative electrode material comprises at least one of hard carbon and soft carbon; the nonaqueous electrolyte contains a film-forming additive and a lithium salt; the film-forming additive comprises vinylene carbonate; and the lithium salt comprises lithium difluorosulfonylimide. Due to excellent performance, the long-life fast-charging cell has broad market prospects.

The invention discloses a silicon-carbon composite anode comprising a silicon source and a carbon source, wherein silicon source is monatomic silicon, the particle size distribution is 100 nm to 80 microns, and the mass of the silicon source accounts for 10-80% of the total mass of the silicon-carbon composite anode; the carbon source comprises a carbon anode material and a conductive agent, the carbon anode material is one or more of carbon fiber, graphite and mesocarbon microbead, and the mass of the carbon anode material accounts for 10-90% of the total mass of the carbon source. According to the silicon-carbon composite anode disclosed by the invention, one-step coating forming, hot pressing flaking, carbonization treatment and high-temperature calcination are carried out on anode slurry prepared by mixing the silicon source with the carbon source, so as to guarantee that the silicon material is effectively dispersed in a carbon skeleton, the prepared silicon-carbon anode can effectively relieve the volume expansion of the silicon material in charging and discharging processes in a circulation process and guarantee excellent cycle performance of the battery; the silicon-carbon composite anode is prepared by one-step coating forming, and no current collector is needed, so that the production process is simplified and the battery is guaranteed to have high energy density; meanwhile, the invention further provides a lithium ion battery containing the silicon-carbon composite anode.

The invention relates to a graphite silicon-based composite anode material for a lithium ion battery and a preparation method thereof. The graphite silicon-based composite anode material comprises a nano-silicon cracked carbon composite material, graphite and a carbon material coating layer. The preparation method comprises the following steps: firstly, nano-silicon is obtained by a high-energy wet mechanical milling method; secondly, nano-silicon and a polymer with high carbon residue are compounded by dispersion polymerization so as to form a polymer/nano-silicon composite microsphere emulsion with nano-silicon inlaid in polymeric microspheres; thirdly, the microsphere emulsion and graphite are compounded; and finally, solid-phase coating is carried out by the use of an organic carbon source, and heat treatment is conducted to obtain the graphite silicon-based composite anode material for a lithium ion battery. By the above method, the problem that nano-silicon is liable to agglomeration, especially agglomeration of nano-silicon from a liquid disperse state to a dry state, due to low granularity and high specific surface energy is solved. The anode material has characteristics of high specific capacity (greater than 550mAh/g), high initial charge discharge efficiency (greater than 80%) and high conductivity.

The invention discloses a method for removing salt by using a fluid battery and application thereof. According to the method, salt removal is performed by a salt-removing fluid battery device, whereinthe salt-removing fluid battery device uses a positive active material as a positive electrode of the fluid battery, a negative active material as a negative electrode of the fluid battery and a saltsolution as an intermediate fluid electrolyte of the fluid battery. According to the invention, organic or inorganic active materials are used as the positive and negative electrode materials of thefluid battery, a salt-removing fluid battery is built in a fixed order, and the salt removing purpose is achieved through charging and discharging; during charging, through respective redox reactionsof the organic active positive and negative electrode materials, under an interfacial effect of an ion exchange membrane, electrodialysis is coupled to remove anions and cations in the salt solution,so that the purposes of removing the salt and removing other ions are achieved. The salt-removing fluid battery used in the invention is simple, low in cost and environment-friendly, shows excellent electrochemical performance, good cycle stability and salt removing capacity, and is applicable to the field of seawater salt removal and the like.

The invention belongs to the field of battery negative electrode materials, and particularly discloses a preparation method of silicon @ carbon composite material with egg yolk shell structure, whichis characterized in that the preparation method comprises the following steps: step 1) mesoporous nano SiOX, molten salt and magnesium powder are mixed and calcined to obtain mesoporous nano silicon;2) mesoporous nano-silicon powder, the surfactant and the aluminum salt prepared in the step 1) are added into a solution at a pH value of 2, and the mesoporous nano-silicon powder, the surfactant andthe aluminum salt are added into the solution at a pH value of 2; 7, coat aluminum hydroxide colloid on that surface of nano silicon to obtain silicon/aluminum hydroxide colloid composite material; 3) silicon/aluminum hydroxide colloidal composite material is mixed with an organic carbon source, carbon is coated on the surface of the silicon/aluminum hydroxide colloidal composite material, and then the silicon/aluminum hydroxide colloidal/carbon composite material is acuquried by carbonizing operation; 4) aluminum hydroxide colloid of the material obtained in the step 3) is removed by using an acid solution and/or an alkali solution to prepare the silicon @ carbon composite material with the egg yolk shell structure. The invention can stably prepare the silicon @ carbon composite materialwith the egg yolk shell structure, and the material has excellent electrical performance.

The invention provides a modification method of a lithium nickelate, cobaltate and manganate ternary material. The method comprises the step that after a lithium nickelate, cobaltate and manganate material is subjected to vapor phase deposition under the conditions of carbon source gas and protective gas, a carbon-coated modified lithium nickelate, cobaltate and manganate material is obtained. The modification method provided by the invention has the benefits that carbon deposits on the surface of the lithium nickelate, cobaltate and manganate ternary material through a vapor phase deposition method, so that carbon coating is realized; by adopting simpler processes, with the aid of the protective gas, the ternary material is carbon-coated, so that the problem of lithium nickelate reduction in the coating process of a traditional ternary material is effectively solved, and the coating of a carbon layer on the surface of the ternary material is realized; through the lithium nickelate, cobaltate and manganate ternary material coating carbon, the first-time charging and discharging efficiencies are improved, the lithium ion diffusion coefficients and the electronic conductivity of the material are improved, and the electrochemical performance of the NCM material is improved. According to the modification method provided by the invention, equipment is relatively simple, the process is less, and the structure is controllable; the material has higher battery capacity, cycle performance and rate capability.

The invention provides a positive electrode material of a lithium cell. The positive electrode material is characterized by comprising a layered composite solid solution and SnO2 dispersed in the layered composite solid solution; the layered composite solid solution is xLi2MnO3*yLiMO2, wherein the M is selected from one or more of Mn, Ni, Co, Cr, Ti and Al, the x and the y are mole contents, and (2x+y)/(x+y) is larger than or equal to 1.2 and also smaller than or equal to 1.6; and in the layered composite solid solution, the content of the Mn is not less than 50% based on the total mole content of the Mn and the M. The invention further provides a preparation method of the positive electrode material of the lithium cell, and the lithium cell utilizing the positive electrode material. A cell prepared from the positive electrode material disclosed by the invention has high cycle performance and high first charge and discharge efficiency simultaneously.

The invention relates to a flexible package lithium ion battery silicon negative pole. The flexible package lithium ion battery silicon negative pole consists of a current collector and an active substance layer coating the surface of the current collector, wherein the active substance layer consists of the following substances in percentage by mass: 10-92 percent of silicon-carbon composite material, 2-70 percent of a conductive agent and 5-20 percent of an adhesive; the adhesive refers to polyimide; the porosity of the active substance layer is 30-65 percent, and the compaction density is 1.1-2.0g/cm<3>. Polyimide is dispersed by adopting a proper solvent, and the adhesive subjected to high-temperature polyacylation treatment has extremely high adhesive force, so that the prepared silicon negative pole piece has ultra-strong tension stress, the structure is kept stable in the repeated lithium-ion embedding and separating process, the first charge-discharge efficiency of the silicon negative pole can be obviously improved, and the cycling stability is improved.

The invention provides a cathode of a lithium-ion secondary battery, which comprises a current collector and a cathode material layer covered on the current collector. The cathode material layer is prepared by adopting magnetron sputtering technology under the sputtering power of 1,000 to 5,000 W. By greatly improving the target sputtering power of magnetron sputtering, the prepared lithium-ion secondary battery has high charge/discharge capacitance and excellent cycle performance, and improves the production efficiency of the material, has simple manufacturing process and operation and good electrochemical performance, and greatly improves the primary charge/discharge efficiency and the discharge capacity compared with the reported silicon-based film cathode material.

The invention discloses a lithium battery silicon-carbon nanotube composite cathode material as well as a preparation method and application of the lithium battery silicon-carbon nanotube composite cathode material. The preparation method of the lithium battery silicon-carbon nanotube composite cathode material comprises the following steps of: mixing and uniformly stirring an organic carbon source and nanometer silicon based on the mass ratio of (0.4-9): 1, adding a catalyst to obtain mixed slurry, drying by a closed circulation spray dryer to obtain a precursor, insulating the precursor for 1-5 hours at the temperature of 300-700 DEG C to obtain a sample, feeding the sample in a tube furnace, increasing the temperature to 500-900 DEG C under the mixed gas of gaseous organic carbon source and N2 and Ar2, and naturally cooling to obtain the lithium battery silicon-carbon nanotube composite cathode material. The lithium battery silicon-carbon nanotube composite cathode material has excellent electrochemical properties, high first charge-discharge efficiency up to more than 2000mAh/g, reversible specific capacity of about 1100mAh/g after cycle of 50 weeks, and good specific capacity and cycle performance, and the problems of low first efficiency, large irreversible capacity loss and poor conductivity of silicon when being used to prepare a lithium ion battery cathode are successfully solved.

The invention discloses a preparation method of a silicon-carbon anode material and a lithium ion battery. The preparation method includes: mixing nano-silicon with graphite solid phase, sieving the mixture, mixing the mixture with an amorphous carbon precursor solid phase, sieving the mixture, performing vibrating shaping, and sintering the product to obtain the silicon-carbon anode material. Bymeans of sieving, the graphite, nano-silicon and amorphous carbon precursor are dispersed, so that the surface of graphite can be uniformly coated with the nano-silicon and the surface of nano-siliconcan be uniformly coated with the amorphous carbon precursor; through the vibrating shaping, surface-to-surface contact between the amorphous carbon precursor and the nano-silicon and between the nano-silicon and the graphite is achieved without existence of a gap; through the sintering step, a volatile substance can be slowly volatilized from interior to exterior, so that a problem of forming pores since a huge gas pressure is generated from the volatile substance can be avoided. The silicon-carbon anode material, when being used for producing the lithium ion battery, shows excellent electrochemical cyclic stability.

The invention belongs to the technical field of lithium ion batteries and in particular discloses a positive active material and a preparation method thereof. The positive active material comprises ternary composite oxides, the general formula of the ternary composite oxides is LiaNibCocMndMeO2, wherein M is a doped chemical element, a is more than or equal to 0.97 and less than or equal to1.06, b+c+d+e=1 and e/d is more than or equal to 0.05 and less than or equal to 0.15. The preparation method for the positive active material comprises the following steps: carrying out step S: adding a solution A and a solution C to a base solution for depositing in parallel, and adding a solution B and the solution C to the base solution for depositing in parallel; repeating the step S, then carrying out aging and finally sintering with a lithium source to obtain the positive active material. The element-doped ternary material provided by the invention is improved greatly in the first charge-discharge efficiency and the cycle performance. The preparation method of the positive active material is simple and practicable and is applied to mass production.

Disclosed is a modification method for native graphite materials used for lithium ion batteries. The method comprises the following steps that native graphite powders are placed into an autoclave, dense oxidizing acid, oxidizing salt and hydrochloric acid are used for oxidation treatment, wherein the oxidation treatment proceeds at a temperature ranging from 180 to 250 DEC G, the native graphite materials which are washed or not are centrifugalized, then native graphite materials which are centrifugalized are calcined, semi-modified native graphite materials are gained, silanization film forming treatment is completed on the semi-modified native graphite materials, then tetrahydrofuran is used to wash and dry the native graphite materials, thereby obtaining modified native graphite materials. The modified native graphite materials are capable of satisfying the application of the lithium ion batteries, have the advantages of high cost performance, low costs, large specific capacity, perfect circulative property and higher initial charge and discharge efficiency, and simultaneously are adapted to the negative pole application of high-current charge and discharge lithium ion batteries.