Preparation method of sulfur anion doped lithium-rich cathode material

Abstract

The invention discloses a preparation method of a sulfur anion doped lithium-rich cathode material. The preparation method comprises the steps of weighing quantitative nickel sulfate (NiSO4) and manganese sulfate (MnSO4) according to a molar ratio and dissolving the NiSO4 and the MnSO4 in de-ionized water; then slowly adding an NaOH solution to the abovementioned solution for sedimentation so as to obtain a mixed metal salt sediment in a certain proportion; uniformly mixing a small amount of lithium sulfide powder and lithium salt powder with the mixed metal salt sediment; then putting the mixture in a muffle furnace and heating to 200-500 DEG C for pre-sintering and then heating to 600-1000 DEG C for calcinations so as to obtain sintered powder; and adding an activating agent to the sintered power for activation, drying and then putting the sintered powder to the muffle furnace for sintering at 200-500 DEG C for 3-5 h so as to obtain the sulfur anion doped lithium-rich cathode material. The preparation method of the sulfur anion doped lithium-rich cathode material is simple in operation, the obtained lithium-rich cathode material has relatively good cycling stability and rate discharge performance, and the first efficiency is more than 95%.

Description

technical field [0001] The invention relates to a preparation method of a lithium-rich cathode material doped with sulfur anions, belonging to the field of lithium ion battery manufacturing. Background technique [0002] The market demand for lithium-ion batteries is increasing year by year, and the rapid promotion and use of new energy vehicles has put forward higher requirements for the energy density and power density of lithium-ion batteries. In recent years, lithium-rich cathode materials with higher capacity (capacity greater than 250mAh / g) have been explored, but there are problems of rapid capacity decay, rapid voltage decay, and low initial efficiency during cycling. [0003] At present, the main ways to improve the cycle stability of lithium-ion battery cathode materials are surface coating and ion doping. The main function of surface coating is to coat a thin and stable barrier on the surface of the cathode material, so that the cathode The isolation of the liqui...

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Problems solved by technology

[0006] Chinese patent CN201310087241.X discloses "polyanion-doped lithium-rich layered oxide cathode material and its preparation and application". The gaps are occupied by other metal ions, so that the polyanion compound has a crystal phase structure different from that of the metal oxide cathode material and various outstanding properties determined by this structure. However, the lithium-rich cathode materials doped with polyanions are ubiquitous. The conductivity is low, which causes the capacity decay too fast during the cycle, and the first-time efficiency is not high

[0007] Chinese patent CN200980138690.4 discloses "lithium-rich fluorine-doped metal oxide positive electrode battery material and corresponding battery with high specific capacity". , will cause the initial discharge capacity of the battery to decrease

[0008] Chinese patent CN201210216042.X discloses "Chlorine element-doped modified lithium-ion battery lithium-rich cathode material and its preparation method", although this method successfully solves the problems of rapid initial specific capacity decline and poor rate performance of lithium-rich cathode materials, However, due to the low discharge capacity at room temperature after chlorine doping, lithium-rich materials have low efficiency for the first time.

[0009] Chinese patent CN201310498055.5 discloses "anion-doped manganese-based solid solution positive electrode material and preparation method", which uses anion S 2- , PO4 3- , SiO4 4- , BO3 3- , SO4 2- As a doping element added to the structure of manganese-based solid solution materials, it forms a more stable chemical bond with O to stabilize the position of O in the crystal structure, which significantly improves the stability of the crystal structure, thereby obtaining better electrochemical stability, but , the doping material is limited to manganese-based solid solution materials, and it does not target most of the lithium-ion battery cathode materials, nor does it improve the problem of low initial efficiency of the battery cycle

[0010] In summary, the above-mentioned prior art has largely solved the problems of too fast cycle decay and poor rate cycle of lithium-ion battery cathode materials, but still has not solved the problem of low efficiency of lithium-rich materials for the first time.

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