104results about How to "Good high temperature cycle performance" patented technology

The invention discloses a high-voltage cathode material for a lithium ion battery. The high-voltage cathode material is a clad material, the core material has the general formula of [LiaNibCocMdO2]; the shell material has the general formula of [LipNixCoyMnzO2]; the cathode material of the lithium ion secondary battery has the general formula of[LiaNibCocMdO2] [LipNixCoyMnzO2]; the content of the core material is 50-99.5wt%, the content of the shell material is 0.05-50wt%. The preparation method comprises the steps of preparing the core material; preparing the precursor [NixCoyMnz (OH)2] of the shell material; cladding; and carrying out sintering twice or many times. According to high-voltage cathode material disclosed by the invention, advantages of Ni and Co elements can be given a full play, the high-voltage cathode material has the advantages of high operation voltage and high energy density as well as excellent high-temperature cycle performance and the dissolution amount of Co can be controlled well.

The invention discloses electrolyte for improving a high-temperature property of a lithium manganate battery, and belongs to the technical field of electrolytes for lithium ion secondary batteries. The electrolyte comprises a nonaqueous organic solvent, lithium salt and a cathode film formation additive; and the electrolyte is characterized by further comprising a cyanophenyl fluoride additive and a fluorocarbon surfactant. In the primary charging process, a layer of protection film is formed on the surface of an anode by cyanophenyl fluoride, the decomposing and gas forming of the electrolyte on the surface of the anode are reduced, the dissolving of Mn<2+> ions in positive active materials can be restrained in subsequent processes of charging and discharging, and the high-temperature property of the lithium manganate battery is improved; and by virtue of adding the fluorocarbon surfactant, the surface tension of the electrolyte of the lithium ion secondary battery is reduced, the adsorption and infiltration of a positive sheet, a negative sheet and a membrane on the electrolyte are effectively improved, the stable and uniform state of the electrolyte in the battery is quickly achieved, and the cycle life of the battery can be prolonged. By utilizing the cyanophenyl fluoride additive and the fluorocarbon surfactant, the lithium manganate battery has an excellent high-temperature cycle property.

The invention provides an electrolyte and a secondary lithium battery. The electrolyte comprises a lithium salt, an organic solvent and additives. The additives include fluoroborate and lithium difluorophosphate. When the electrolyte is applied to the secondary lithium battery, the secondary lithium battery simultaneously has excellent high-temperature cycle performance, high-temperature storage performance, low-temperature discharge performance and large-rate charge performance, and the low-temperature lithium precipitation of the secondary lithium battery is also significantly suppressed.

The invention discloses electrolyte of a lithium ion battery. The electrolyte comprises an organic solvent, electrolyte lithium salt and additives, wherein the additives include butanedinitrile, fluorobenzene and lithium tetrafluoroborate; the mass percentage of the fluorobenzene in the electrolyte is 0.1 to 15 percent; the mass percentage of the butanedinitrile in the electrolyte is 0.1 to 10 percent; the mass percentage of the lithium tetrafluoroborate in the electrolyte is 0.01 to 1 percent. By adopting the electrolyte, while the charging upper limit voltage and high temperature intermittent cycling performance of the lithium ion battery are improved, simultaneously the expansion rate of the battery is reduced, the internal resistance is reduced, and the stability and the safety of the lithium ion battery can be improved.

The invention discloses a positive active material and a preparation method and application thereof, and belongs to the technical field of lithium-ion batteries. The positive active material is prepared from LiNi0.82Co0.15Al0.03O2 and LiNi0.34Co0.32Mn0.34O2 at the ratio in mass percent of (60%-85%):(15%-40%), and D50 of the LiNi0.82Co0.15Al0.03O2 and the LiNi0.34Co0.32Mn0.34O2 is 10-15 microns and 1-6 microns respectively. Due to the presence of a grain size difference, the two active materials can be evenly mixed; on one hand, high discharge specific capacity of nickel-cobalt lithium aluminate is kept; and on the other hand, high safety performance and cycle performance of nickel-cobalt lithium manganate are fully developed. Compared with the lithium-ion battery of individually using a nickel-cobalt lithium aluminate or nickel-cobalt lithium manganate positive electrode material and the positive electrode material in a comparative example, the lithium-ion battery prepared from the positive electrode material disclosed by the invention has higher discharge capacity, excellent high-temperature cycle performance and excellent low-temperature performance and safety performance.

The invention discloses a preparation method of a lithium manganate anode material. The preparation method comprises the following steps: (1) preparing a salt-mixture solution; (2) preparing a precipitant solution; (3) slowly pumping the salt-mixture solution and the precipitant solution into a reaction kettle at a pH value of 7-13; (4) weighing manganese dioxide in proportion, adding the manganese dioxide to a mixed solution obtained in the step (3), continuously stirring, ageing for 5-20 hours, then separating solid-liquid products, and washing an obtained precursor with deionized water to alkalescence; (5) adding a lithium source and the washed precursor to a ball-milling tank, carrying out ball-milling for 2-5 hours, and then drying at the temperature of 80-120 DEG C, thus obtaining a precursor material; and (6) respectively roasting the obtained precursor material two times, breaking the material obtained by sintering, and sieving, thus obtaining the lithium manganate anode material. The preparation method is simple; the prepared lithium manganate anode material has high capacity and excellent high-temperature cycle performance.

The invention discloses a coated-modified lithium manganese positive electrode material and the preparation method thereof. A manganese source compound, an M source compound and a lithium source compound are taken as raw material for preparing LiaMn2 -bMbO4 particles, and then are mixed with molten solvent and A-source compound, so as to obtain coated-modified lithium manganese positive electrode material. Compared with the prior art, the LiaMn2-bMbO4 particles are similar to spheres in shape and are in crystal face connection through curved surfaces which have no clear edges; on one hand, the LiaMn2 -bMbO4 particles have very small specific surface area, so that molten solvent and coating material are more evenly dispersed on the surfaces of the particles, and the control to average thickness of a coating is facilitated; on the other hand, the features have very small surface energy, the coating material is enabled to be more easily to be combined with the LiaMn2 -bMbO4 particles to form the coating. Therefore, the coated-modified lithium manganese positive electrode material has an excellent high temperature cycling performance.

The invention provides a preparation method of a negative electrode with high compaction, excellent high-temperature performance and high energy density. Carbon is deposited in holes and a surface ofnatural spherical graphite by pyrolysis of organic alkane, the defects in the natural spherical graphite and on the surface of the natural spherical graphite are recovered, high-speed stirring and uniform dispersing are performed after mixing with asphalt, and the negative electrode material with high compaction and high energy density is obtained by carbonization. The negative electrode materialprepared by the method has excellent high-temperature cycle performance, and the problem of poor high-temperature cycle property in the prior art is solved.