Cathode material for lithium ion batteries and preparation method thereof

Abstract

The invention discloses a cathode material for lithium ion batteries. The cathode material is a core-shell structure. The ''core'' of the core-shell structure is a cathode active material, and the ''shell'' of the core-shell structure is a carbon layer containing discontinuous nano-LixMOy. The carbon layer uniformly coats the cathode active material. The LixMOy is one or more of LiAlO2, Li2TiO3 or Li2ZrO3. The cathode active material is one or more of lithium cobalt oxide, LiNixCoyMn1-x-yO2, lithium manganate, lithium nickel manganese oxide and LiNi_(0.7)Co_(0.3-x)Al_xO_2. A preparation method of the cathode material comprises the following steps: adding the cathode active material, nano-LixMOy, phenol, aldehyde and a catalyst into a surfactant and uniformly dispersing, carrying out vacuum filtration, washing and drying, calcining in the inert atmosphere and cooling to prepare the cathode material. The cathode material for lithium ion batteries has good electrochemical stability. A battery prepared from the cathode material has excellent cycle and rate performance, and capacity retention ratio of the battery is high.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a positive electrode material of a lithium ion battery and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, wide operating temperature range, no memory effect, and long cycle life. They are widely used in digital products and power tools, and are considered to be ideal power sources for next-generation electric vehicles. The development of lithium-ion batteries with high energy density, high power density, and high safety has broad market prospects. Cathode material is one of the key materials restricting the performance of lithium-ion batteries. Due to the high potential of the positive electrode material, the positive electrode material in the delithiated state has strong oxidative properties, and is prone to side reactions with organic electrolytes to generate gas, causing safety hazards ...

AI Technical Summary

Problems solved by technology

Commonly used coating substances are mostly metal or nonmetal oxides, metal fluorides, phosphates, carbon materials and conductive polymers, etc., which can prevent the positive electrode material particles from directly contacting the electrolyte. However, the oxidation of metal or nonmetal Although compounds, fluorides, and phosphates have certain electronic conductivity, they have no ion conductivity; carbon materials and conductive polymers have good electronic conductivity, but relatively poor ion conductivity.

After coating the positive electrode material particles with the above materials, although the safety and cycle performance of the battery are improved to a certain extent, the capacity and rate performance of the battery decrease significantly, and the ideal electrical performance cannot be achieved.

Images