Nickelic cathode material rich in lithium and preparation method thereof

Abstract

The invention discloses a nickelic cathode material rich in lithium and a preparation method thereof. The character chemical formula of the nickelic cathode material rich in lithium is Lil+nNi0.7+xCo0.3-x-y-zMnyMzO2, wherein x is larger than 0.00 and less than 0.3, y is larger than 0.01 and less than 0.1, z is larger than or equal to 0.00 and less than 0.03, the sum of x, y and z is less than 0.3, and n is larger than 0.00 and less than 0.25. The nickelic cathode material rich in lithium is synthesized under the state rich in lithium, so that the cation mixing phenomenon can be effectively inhibited, and reliance on oxygen in the sintering process is reduced. Meanwhile, Li left on the surface of a particle is washed away with a washing coating agent solution, and therefore, the content and the pH value of the impurity Li of a finished product are reduced. The nickelic cathode material rich in lithium prepared by the method is uniformly distributed in grain size and regular in the crystal shape, the content and the pH value of the impurity Li of the finished product are low, the high-temperature ballooning rate of batteries at 85 DEG C is low, the reversible capacity between 3.0 V-4.3 V is larger than 180 Ah/g, and the nickelic cathode material rich in lithium has a good cycling performance.

Description

technical field [0001] The invention relates to a lithium-ion battery cathode material, in particular to a lithium-rich and high-nickel cathode material and a preparation method thereof. Background technique [0002] There are three characteristics of the current development of the battery industry in the world. One is the rapid development of green and environmentally friendly batteries, including lithium-ion batteries, nickel-hydrogen batteries, etc.; the second is the transformation of primary batteries into batteries, which is in line with the sustainable development strategy; Light and thin direction development. Among commercialized rechargeable batteries, lithium-ion batteries have the highest volume specific energy and mass specific energy, are rechargeable and pollution-free, and have three characteristics of the current battery industry development, so they have a relatively rapid growth in developed countries. The development of telecommunications and information...

AI Technical Summary

Problems solved by technology

Solid-phase synthesis is generally sintered by mixing nickel-cobalt-manganese compounds, lithium sources, and doping element compounds, but this solid-phase mixing method cannot achieve uniformity at the atomic level, and the performance is difficult to fully exert; although liquid-phase methods can solve this problem problems, but the process is complicated and the output is low

From the perspective of actual production, the preparation of positive electrode materials by the solid phase method is undoubtedly more suitable for large-scale production, but the production conditions are harsh and difficult to control, especially the strict requirements on the sintering atmosphere, which must be sintered in an oxygen atmosphere

In addition, the control of the sintering temperature is also difficult, because the temperature fluctuation range is narrow, the reaction will not be sufficient if the temperature is low, and the decomposition will occur if the temperature is high, and it is difficult to completely react.

Moreover, Ni exists in the synthesis of high-nickel cathode materials. 2+ Difficult to fully submit to Ni 3+ Transformation, will lead to Ni during high temperature sintering 2+ and Li + The phenomenon of cation mixing will also lead to poor thermal stability and high initial irreversible capacity of the material.

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