Composite Coated Ternary Precursor for Uniform Cathode Protection
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Solution Overview
Problem
Ternary cathode materials for lithium-ion batteries face safety performance issues despite high specific capacity and cycle performance, with existing coating methods increasing sintering stages, labor costs, and material segregation risks, while achieving limited improvement in safety and stability.
Innovation Solution
A composite coated ternary precursor is developed, comprising a ternary precursor with a coating layer formed by a precipitation reaction between specific metal ions and polyanions, which is evenly distributed to enhance material stability and electrochemical performance, using a one-step precipitation method that reduces material segregation and increases particle sphericity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coating elements are added in a sintering stage, then coating can be formed on ternary cathode materials, but the number of sintering times increases and coating material uniformity deteriorates
Solution Approach 1:
The coating layer is formed on the precursor particles before the sintering process. The precipitation reaction occurs during precursor preparation, creating a coating that will be incorporated into the final cathode material during sintering. This eliminates the need for separate post-sintering coating steps and multiple sintering cycles.
Solution Approach 2:
The coating formation process is merged with the precursor preparation process. Both the precursor synthesis and coating deposition occur in the same precipitation reaction step, combining two previously separate operations into one integrated process that improves efficiency and uniformity.
2Reliability
If single element coating is applied on precursor surface, then coating can be formed, but improvement effect is limited and labor cost increases due to multi-stage coating
Solution Approach 1:
The coating layer comprises multiple elements (Mg, Sc, Ti, V, Cr, Cu, Zn, Ge, Zr, Nb, In, Sb, Tb, Ta, Re, Ir, Pb, Bi combined with SiO3, AlO2, B4O7, SO4, PO4, BO3, MoO4, or WO4) that work synergistically to improve both safety and electrochemical performance. This multi-element composite coating achieves superior results compared to single-element coatings while requiring only one coating step.
Solution Approach 2:
The multi-element coating layer performs multiple functions simultaneously: it improves safety by stabilizing the crystal structure, enhances electrochemical performance through synergistic effects of different elements, and reduces manufacturing complexity by achieving all these benefits in a single coating operation rather than multiple sequential coatings.
3Reliability
If multi-stage coating is performed, then coating coverage can be improved, but operation difficulty increases and material segregation risk increases
Solution Approach 1:
The coating is formed on the precursor particles before sintering, ensuring that the coating material is already in place and uniformly distributed on the particle surfaces before the final material synthesis. This preliminary coating action prevents material segregation that could occur if coating were attempted after sintering.
Solution Approach 2:
The precipitation reaction conditions (pH control, temperature, stirring speed, reactant concentrations) are optimized to ensure uniform nucleation and growth of the coating layer across all precursor particles. This homogeneous coating process eliminates the need for multiple coating stages and prevents material segregation during subsequent handling and sintering.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite coating improves the stability and cycle performance of ternary materials by forming a protective layer and inhibiting phase transitions, reducing oxygen defects and side reactions, while maintaining energy density and capacity.
Implementation Method 1
the coating layer is obtained by a precipitation reaction between a first metal ion and a first polyanion
Data Source
AI summary
A compositely coated ternary precursor, and a preparation method therefor and use thereof are provided. The material includes a ternary precursor and a coating layer attached to a surface of the ternary precursor, wherein the coating layer is obtained from a precipitation reaction of a first metal ion and a first polyanion. The metal ion and the polyanion can undergo a precipitation reaction to form a precipitate, to form a uniformly distributed coating layer on the surface of the ternary precursor. After the coated precursor is sintered into a cathode material, part of the coating can form a protective layer on the surface of the material; and the other part of the coating can permeate into the material to form bulk phase doping.