Concentration gradient monocrystal positive electrode material and preparation method thereof

Abstract

The invention discloses a concentration gradient monocrystal positive electrode material and a preparation method thereof, and the preparation method comprises the following steps: placing nickel hydroxide particles as a carrier in a reaction kettle, adding sodium hydroxide solution as a precipitant, adding ammonia water as a complexing agent, and controlling the temperature in the reaction kettleto be 50-60 DEG C, wherein the pH value is 10-12, and the atmosphere is nitrogen; pumping manganese salt solution into the reaction kettle at a first feeding rate and pumping cobalt salt solution into the reaction kettle at a second feeding rate, so that the manganese salt and the cobalt salt are deposited into pores of the nickel hydroxide particles to synthesize a precursor; mixing the precursor with lithium salt, and carrying out roasting treatment to obtain the concentration gradient monocrystal positive electrode material. The preparation method is simple in process, low in cost, stablein material structure and the like; the prepared monocrystal positive electrode material has the advantages of a concentration gradient material and a monocrystal material, can solve the problem thatparticles of the material are broken, and effectively improves the cycle performance and the safety performance of the material.

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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