Method for coating nickel cobalt lithium manganate positive-electrode material with calcium fluophosphate

Abstract

The invention provides a method for coating a nickel cobalt lithium manganate positive-electrode material with calcium fluophosphate. The method comprises the following steps: a) dissolving the nickel cobalt lithium manganate positive-electrode material in deionized water for dispersion; b) first adding calcium nitrate solution and then adding ammonium fluoride solution into the nickel cobalt lithium manganate positive-electrode material dispersed by the step a), with the molar ratio of the calcium nitrate solution to the ammonium fluoride solution being 1:2, and reacting to produce the calcium fluophosphate; c) stirring a suspension liquid obtained in the step b) for 2-4 hours at the temperature of 75-85 DEG C, evaporating the suspension liquid to dryness, and thermostatically drying for 12 hours at the temperature of 120 DEG C; d) putting the dried material of the step c) into a muffle furnace for baking heat treatment, and then naturally cooling to obtain the calcium fluophosphate coated nickel cobalt lithium manganate positive-electrode material. According to the method, the nickel cobalt lithium manganate positive-electrode material is coated with the calcium fluophosphate, higher initial capacity of the nickel cobalt lithium manganate positive-electrode material itself can be maintained, dissolving in electrolyte of transition metals in the nickel cobalt lithium manganate positive-electrode material during a charge-discharge cycle process can be inhibited, and capacity retention rate of the nickel cobalt lithium manganate positive-electrode material can be improved.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a method for coating nickel-cobalt lithium manganese oxide cathode material with calcium fluorophosphate. Background technique [0002] Lithium-ion battery is a new generation of green high-energy battery, which has outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge, and no memory effect, so it is very popular among people. In lithium-ion batteries, the positive electrode material is the most important part. At present, the most studied positive electrode materials are lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel oxide and lithium nickel cobalt manganese oxide. It has the advantages of high specific capacity, good discharge rate, excellent cycle performance, good safety, low cost, and relatively low price, so it is very popular. However, during the charge and discharge process of nickel ...

AI Technical Summary

Problems solved by technology

However, during the charge and discharge process of nickel-cobalt lithium manganate cathode material, the electrolyte will dissolve the transition metal in the cathode material, resulting in poor cycle performance and unstable electrochemical performance of the battery. Therefore, this problem needs to be solved urgently.

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