Concentration gradient single crystal cathode material and preparation method thereof

Abstract

The invention discloses a single-crystal cathode material with a concentration gradient and a preparation method thereof. The preparation method comprises: placing nickel hydroxide particles in a reaction kettle as a carrier, adding sodium hydroxide solution as a precipitant, and adding ammonia water as a complexing agent. agent, and control the temperature in the reactor to be 50-60 degrees Celsius, the pH value to be 10-12, and the atmosphere to be nitrogen; pump the manganese salt solution into the reactor with the first feed rate, and pump the cobalt into the reactor with the second feed rate Salt solution, so that manganese salts and cobalt salts are deposited into the pores of nickel hydroxide particles to synthesize precursors; the precursors are mixed with lithium salts and then roasted to obtain single-crystal cathode materials with a concentration gradient. The preparation method has the advantages of simple process, low cost, and stable material structure. The prepared single-crystal cathode material with a concentration gradient has the advantages of both the concentration gradient material and the single-crystal material, and can avoid the particle breakage of the material while effectively improving the material. Cycle performance and safety performance.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, in particular, the invention relates to a single-crystal cathode material with a concentration gradient and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used as efficient energy storage and conversion devices. However, the specific capacity of cathode materials is low, which restricts the improvement of specific energy of lithium-ion batteries. Among the current several cathode materials, ternary cathode materials have obvious advantages in discharge specific capacity, voltage and structural stability. At present, there are two main types of ternary cathode materials: secondary particles and single crystals. Compared with single crystal materials, secondary granular materials have poor structural stability, are easy to pulverize during circulation, and have more side reactions with electrolyte. By synthesizing the secondary particle mat...

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Problems solved by technology

Compared with single crystal materials, secondary granular materials have poor structural stability, are easy to pulverize during circulation, and have more side reactions with electrolyte

However, as the cycling progresses, the Ni on the surface of the single crystal cathode material tends to form the non-electrochemically active phase NiO, resulting in a decrease in the material capacity.

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