Method for preparing anode active substance, anode active substance, anode and battery

Abstract

The invention provides a method for preparing an anode active substance, the anode active substance prepared by the method, an anode comprising the anode active substance and a battery comprising the anode. The method for preparing the anode active substance comprises the step of sintering a mixture which comprises a raw material 1 and a raw material 2; the raw material 1 comprises a lithium source, an iron source and a phosphorus source; and the raw material 2 is one or more of compounds represented by LiDcO2, LiiNi1-d-eCodMneO2, LiNi1-f-gCofAlgO2, LixNi1-yCoO2 and LimMn2-nEnOj, wherein D is one of B, Mg, Al, Ti, Cr, Fe, Cu, Zn, Ga, Y, La and V; c is more than 0 and less than or equal to 3, i is more than or equal to 0.9 and less than or equal to 1.2, d is more than or equal to 0 and less than or equal to 0.5, e is more than 0 and less than or equal to 0.3, f is more than or equal to 0 and less than or equal to 0.5, g is more than or equal to 0 and less than or equal to 0.3, x is more than or equal to 0.9 and less than or equal to 1.1, and y is more than or equal to 0 and less than or equal to 1; E is one of boron, magnesium, aluminum, gallium and transition metallic elements except Mn; m is more than or equal to 0.9 and less than or equal to 1.1, n is more than or equal to 0 and less than or equal to 1, and j is more than 1 and less than 6; and due to the sintering condition, the prepared anode active substance comprises a lithium ferrous phosphate crystal. The battery made of the anode active substance prepared by the method provided by the invention has good specific capacity of quality and good cycle performance.

Description

technical field [0001] The present invention relates to a preparation method of a positive electrode active material, a positive electrode active material prepared by the preparation method, a positive electrode comprising the positive electrode active material and a battery comprising the positive electrode, in particular to a positive electrode activity of a lithium secondary battery The preparation method of the material, the positive electrode active material prepared by the preparation method, the positive electrode including the positive electrode active material and the battery including the positive electrode. Background technique [0002] Lithium secondary batteries using lithium intercalation compounds as positive active materials have been widely used in various portable electronic products and communication tools due to their advantages such as high battery voltage, high specific energy, long cycle life, and small self-discharge. Developed as a clean power source...

AI Technical Summary

Problems solved by technology

[0003] LiCoO is currently used as the positive electrode active material of lithium secondary batteries 2 Due to the advantages of high open circuit voltage, large specific capacity, and long cycle life, it has been widely used, but its application is limited due to the lack of cobalt resources, high price and certain toxicity; spinel LiMn 2 o 4 Due to the fast decay of charge-discharge capacity at high temperature, LiNiO 2 Due to the difficulty of synthesis and the existence of safety problems, the two have not been used in large quantities at present.

[0004] LiFePO with olivine structure 4 Since it was discovered in 1997 that it can be used as the positive electrode active material of lithium-ion batteries, it has received extensive attention; it has a stable discharge voltage platform around 3.4V, and has a wide range of raw materials, good thermal stability, high theoretical capacity, and environmental friendliness. Pure LiFePO 4 The electronic conductivity is low, and the current common improved LiFePO 4 The electron conductivity method has the LiFePO 4 Medium-doped LiCoO 2 and so on to form a new positive electrode active material, although the electronic conductivity of the positive electrode active material has improved, the improvement effect is still not ideal

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