36results about How to "Increase irreversible capacity" patented technology

The invention discloses a preparation method of a silicon and carbon-coated graphene composite cathode material. The technical problem to be solved is to enhance the electronic conductivity of the silicon-based cathode material, buffer the volume effect produced in the process of deintercalation of the lithium in the silicon-based cathode material and enhance the structure stability in the circulation process of the material at the same time. The material is prepared by using a spray drying-thermally decomposing treatment process in the invention. The preparation method comprises the following steps of: evenly dispersing nano silicon and graphite micro powder in a dispersion solution of oxidized graphene, carrying out thermal treatment under an inert protection atmosphere after spray drying, subsequently cooling along a furnace to obtain the silicon and carbon-coated graphene composite cathode material. The extra binder does not need to add in the process of manufacturing balls in the invention and the outer oxidized graphene is thermally reduced in situ to graphene in the thermal treatment process of the composite precursor, so that the process is simple and easy to operate; and the practical degree is high. The prepared composite material has the advantages of great reversible capacity, designable capacity, good cycling performance and high-current discharging performance, high tap density and the like.

Disclosed is a cathode active material providing a cell performance that is not adversely affected by overdischarge, and a lithium secondary cell using the same. More particularly, the cathode active material for a lithium secondary cell comprises a lithium-transition metal oxide capable of lithium ion intercalation/deintercalation, wherein the cathode active material further comprises a lithium manganese oxide having a layered structure represented by the following formula 1 as an additive:[formula 1] LiM_xMn_1-x0₂ wherein, x is a number satisfying 0.05 x<0.5, and M is at least one metal selected from the group consisting of Cr, Al, Ni, Mn and Co. The lithium manganese oxide of formula 1 used as an additive for a cathode active material of a lithium secondary cell provides lithium ions in such an amount as to compensate for an irreversible lithium ion-consuming reaction at an anode, or more, thereby providing a lithium secondary cell which is low in capacity loss by over-discharge.

The invention discloses a water-soluble three-dimensional network type electrode binding agent, comprising a water-soluble polymer polyelectrolyte. Molecular chains of the polyelectrolyte contain active groups; the molecular chains of the polyelectrolyte are cross-linked and bridged by a cross-linking agent to form a three-dimensional network type molecular structure. The invention also disclosesa preparation method of the binding agent, an electrode piece prepared by utilizing the binding agent, and electrochemical devices. In the water-soluble three-dimensional network type electrode binding agent disclosed by the invention, the water solubility is good, the viscosity is adjustable, and the tensile strength and the Young modulus are controllable; in the carbon electrode piece prepared by the electrode binding agent, the mechanical property is good, the phenomenon of common material falling of the electrode piece can be avoided, the irreversible capacity is low in the first chargingprocess, the reversible capacity is high, and electrochemical devices such as lithium-ion batteries and super capacitors and the like with excellent circulating performance can be manufactured.

The invention provides PC (Propylene Carbonate)-based high-voltage electrolyte. The PC-based high-voltage electrolyte comprises a non-aqueous solvent, and a lithium salt and an additive which are dissolved into the non-aqueous solvent; the non-aqueous solvent comprises propylene carbonate (PC) and linear carboxylate; the mass percent content of the propylene carbonate (PC) in the electrolyte is 15%-50%; the additive comprises fluoroethylene carbonate, ethylene sulfate and a dinitrile compound. A solvent system and the additive are optimally combined and used to generate a cooperative effect and are used for a lithium ion battery, so that good cycle life, low-temperature discharging properties and high-temperature storage properties of the battery can still be kept under high voltage.

To provide a lithium-ion secondary battery including a first electrode including a first electrode active substance and a second electrode including a second electrode active substance and a third electrode active substance. The second electrode active substance has higher charge and discharge efficiency than the first electrode active substance. The third electrode active substance has lower charge and discharge efficiency than the second electrode active substance. The product of the capacity of the second electrode active substance and the difference between the charge and discharge efficiency of the second electrode active substance and charge and discharge efficiency of the first electrode active substance is greater than the product of the capacity of the third electrode active substance and the difference between the charge and discharge efficiency of the first electrode active substance and the charge and discharge efficiency of the third electrode active substance. The compounding proportion of the second electrode active substance in the total of the second electrode active substance and the third electrode active substance is less than the compounding proportion of the third electrode active substance in the total of the second electrode active substance and the third electrode active substance.

The invention discloses a sodium ion battery negative electrode material and a preparation method thereof, and the preparation method comprises a preparation method (1) or a preparation method (2). The preparation method (1) is: firstly activating the soft carbon and then coating the hard carbon; the preparation method (2) is: firstly activating the hard carbon and then coating the soft carbon. The preparation method firstly introduces a large number of developed pore structures by activating the soft carbon/hard carbon to provide more storage space for sodium ions, which is favorable for theincrease of material capacity; then the coating of a hard carbon/soft carbon precursor can effectively cover the defects and edge faces caused by the activation, reduce the irreversible capacity losscaused by the insertion and removal of sodium ions, and effectively improve the first-week coulomb efficiency. The sodium ion battery negative electrode material of the invention has the advantages oflow cost, high capacity and high first-week coulomb efficiency, and high cost performance; in addition, the preparation method of the invention is simple and suitable for commercial application.

The invention discloses a submicron copper sulfide/sisal fiber carbon anode material for a lithium ion battery and a preparation method thereof. The preparation method comprises the following steps of carbonizing, grinding and sieving the sisal fibers into a tubular atmosphere oven, uniformly mixing with copper nitrate and thiourea in the solution, transferring into a reaction kettle to carry out hydrothermal reaction, and filtering, cleaning and drying an obtained sample to obtain the submicron copper sulfide/sisal fiber carbon anode material for the lithium ion battery. Copper sulfide particles with irregular shapes and the particle sizes of 200-500 nm are uniformly dispersed in the surface and holes of sisal fiber carbon with a multilevel pore structure in the anode material, and a mass ratio of the copper sulfide to a compound is 1 to 5. The submicron copper sulfide/sisal fiber carbon anode material for the lithium ion battery, which is prepared by the invention, has better cycle performance and rate performance.

The invention discloses a high-performance carbon negative electrode PTCDA hard carbon material and a preparation method thereof, a product can be prepared by solid-phase sintering of perylenetetracarboxylic dianhydride, i.e., a blocky carbon material is obtained by high-temperature sintering of a perylenetetracarboxylic dianhydride negative electrode material under an inert gas, and the perylenetetracarboxylic dianhydride is directly sintered into a carbon material, so that the used raw materials are simple, other doping materials, such as graphite, etc., are not needed, the industrial production cost is low, raw materials are easy to obtain, and the preparation method is simple, environment-friendly and non-toxic. The carbon material is obtained by directly sintering perylenetetracarboxylic dianhydride, the preparation process is low in sintering temperature, is easier to realize, is simple to control and is easier for industrial production, and the obtained PTCDA organic carbon shows good cycle performance and capacity property when being used as a negative electrode material of a lithium ion battery and has better cycle stability compared with the traditional graphite.

The invention provides a non-aqueous electrolyte of a lithium ion battery and the lithium ion battery containing the non-aqueous electrolyte. The lithium ion battery non-aqueous electrolyte comprisesa lithium salt, a non-aqueous organic solvent and an additive. The additive comprises a compound having a structural formula represented by a formula I, R1 is C or N, R2 is a hydrogen or alkali metalelement, and R3 and R4 are alkali metal elements. The additive can optimize a positive electrode/electrolyte interface under a 4.4 V high-voltage system. A stable CEI film is formed on the surface ofa positive electrode to effectively prevent dissolution of transition metal, and the additive is further complexed with F<->, so that HF can be effectively removed, oxygen free radicals generated fromthe positive electrode material are absorbed, the stability of the positive electrode material is improved, and the charge-discharge reversibility in a cycle is improved. Meanwhile, the substituted alkali metal element can prevent active hydrogen connected to the nitrogen-containing heterocyclic nitrogen from reacting with a large amount of lithium ions in the electrolyte to consume the lithium ions. Therefore, by adopting the additive, the first coulombic efficiency, the cycle performance and the high-temperature performance of the lithium ion battery can be improved.

The invention relates to a preparation method of lithium ion battery cathode slurry, and belongs to the technical field of lithium ion battery slurry. According to the main technical scheme, the preparation method comprises the following steps of: (1) adding 1-10 parts of a conductive agent and 100 parts of an active substance into a stirring tank for uniform stirring; (2) adding 20-80 parts of absolute ethyl alcohol into the stirring tank, and performing stirring until the absolute ethyl alcohol is completely infiltrated; (3) adding 20-80 parts of an N-methyl pyrrolidone solution into the stirring tank for uniform stirring; and (4) adjusting the viscosity. According to the preparation method, the conductive agent and the active substance powder are premixed, then the absolute ethyl alcohol is added for dispersion, then the dissolved polyvinylidene fluoride solution is added, and the obtained slurry is good in dispersion effect; and compared with a traditional process, absolute ethyl alcohol and N-methyl pyrrolidone are used as solvents, the use amount of the N-methyl pyrrolidone is reduced, the cost is saved, the emission of harmful substances is reduced, and the method has important significance in environmental protection.

The invention discloses a lithium ion battery pre-lithiation agent and a preparation method and application thereof, the chemical formula of the lithium ion battery pre-lithiation agent is Li5FeO4 (at) C, the structure of the lithium ion battery pre-lithiation agent is secondary particles agglomerated by Li5FeO4 primary particles, and the surfaces of the Li5FeO4 primary particles are coated with carbon. The carbon source and the soluble salt of Fe are mixed, Fe ions are attached to the carbon source, hydroxide with small particles and good dispersity can be formed after ammonia water is added, then nanoscale oxide is obtained through solvothermal reaction, the carbon source plays a role in blocking among the particles in the subsequent sintering process, growth of primary particles is slowed down, and the performance of the catalyst is improved. The pre-lithiation agent prepared by the method is relatively small in primary particle, relatively short in Li < + > removal path during charging and good in rate capability. The pre-lithiation agent can provide enough Li < + > when the battery is charged for the first time, so that an SEI film is generated on the surface of a negative electrode, the loss of Li < + > in a positive electrode material is reduced, and the coulombic efficiency and the capacity of the lithium ion battery are improved.

The invention discloses an explosion-proof forklift lithium battery and a preparation method thereof, and belongs to the technical field of lithium batteries. The explosion-proof forklift lithium battery comprises an explosion-proof shell, and a positive electrode, a negative electrode, an electrolyte and a diaphragm which are arranged in the explosion-proof shell. The positive electrode comprises a positive electrode material and a positive current collector, the negative electrode comprises a negative electrode material and a negative current collector, and the positive electrode material comprises a positive electrode active material, a positive electrode conductive agent and a positive electrode binder; the negative electrode material comprises a negative electrode active material, a negative electrode conductive agent and a negative electrode adhesive; the positive electrode active material is modified lithium manganate, the positive electrode conductive agent and the negative electrode conductive agent are different in component, the positive electrode binder and the negative electrode binder are different in component, and the negative electrode active material is graphene. According to the present invention, the positive and negative active materials, the conductive agents, the binders, the electrolyte and the like of the lithium battery are optimized, so that the cycle capacity retention ratio of the battery is remarkably improved, and the service life of the lithium battery is greatly prolonged.

The present invention relates to: a cathode additive for a lithium secondary battery, which has a high irreversible capacity and thus can be effectively applied to a high capacity battery involving the use of an anode having a high energy density; and a manufacturing method therefor.