Lithium-rich manganese-based anode material and preparation method thereof

Abstract

The invention relates to a lithium-ion secondary battery anode material technology, in particular to a lithium-rich manganese-based anode material Li(Li(1-2x) / 3Nix-aMyMn(2-x) / 3-b)O2 (M is Co, Al, Ti, Mg and Cu) and a preparation method thereof. A general formula of the lithium-rich manganese-based anode material is as follows: Li(Li(1-2x) / 3Nix-aMyMn(2-x) / 3-b)O2 (M is Co, Al, Ti, Mg and Cu), wherein x is more than 0 and less than or equal to 0.5, when M is Co and Al, y is more than 0 and less than 2x, a is equal to b, and b is equal to y / 2; when M is Ti, y is more than 0 and less than (2-x) / 3, a is equal to 0, and b is equal to y; and when M is Mg and Cu, y is more than 0 and less than x, a is equal to y, and b is equal to 0. The invention has high specific discharge capacity, excellent normal temperature and high temperature cycle performance, good safety, low raw material cost and production cost, and very high cost-performance ratio.

Description

technical field [0001] The present invention relates to lithium-ion secondary battery anode material technology, particularly lithium-rich manganese-based anode material Li[Li (1-2x) / 3 Ni x-a m y mn (2-x) / 3-b ]O 2 (M=Co, Al, Ti, Mg, Cu) and its preparation method. Background technique [0002] Lithium-ion battery cathode material is the key raw material of lithium-ion batteries. Its performance determines the performance of lithium-ion batteries, and its price determines the cost of lithium-ion batteries. At present, the cathode materials on the market are mainly lithium cobalt oxide. , materials such as spinel lithium manganate, nickel cobalt lithium manganese oxide, nickel cobalt lithium oxide, and lithium iron phosphate also occupy a certain market share. Lithium cobaltate is the first positive electrode material to be commercialized. It has stable performance, simple preparation, and mature technology. However, the global cobalt resources are in short supply, and my...

AI Technical Summary

Problems solved by technology

Li[Li (1-2x) / 3 Ni x mn (2-x) / 3 ]O 2 The material is Li 2 MnO 3 with LiMn 0.5 Ni 0.5 o 2 The solid solution is a composite structure, which has a high specific capacity at a higher charging voltage. It has been reported in the literature that Li 1.2 Ni 0.2 mn 0.6 o 2 The initial discharge specific capacity of the material is 288mAh / g when charged and discharged at 2-4.8V with a current of 20mA / g, but its cycle stability is very poor, and the discharge specific capacity drops to 213mAh / g after 30 cycles

From the reported Li[Li (1-2x) / 3 Ni x mn (2-x) / 3 ]O 2 From the perspective of materials, there are obvious defects. First, the Li [Li (1-2x) / 3 Ni x mn (2-x) / 3 ]O 2 The high specific capacity of the material is obtained by charging and discharging at a very low rate. When the rate increases, the specific capacity drops rapidly, and the rate performance of the material is poor; second, Li[Li (1-2x) / 3 Ni x mn (2-x) / 3 ]O 2 The material can only get a higher specific capacity when it is charged above 4.5V. If it is charged at a lower voltage, the specific capacity obtained is much lower than that of lithium cobalt oxide and other materials.

To sum up, the current Li[Li (1-2x) / 3 Ni x mn (2-x) / 3 ]O 2 The performance of the material does not meet the requirements of practical applications, so it is urgent to improve its performance so that it can have better performance and realize industrial production as soon as possible

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