High-Nickel Positive Electrode Material With Rare-Earth Surface Network
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Solution Overview
Problem
High-nickel layered materials in lithium-ion batteries suffer from poor cycling stability during deep charging and discharging, limiting their commercial applications.
Innovation Solution
A positive electrode material is modified with a rare earth element and/or a refractory metal element, forming a fast ion conductive network on the surface and a stable structure with high bond energy within the bulk phase, improving cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-nickel layered material is used as positive electrode material, then capacity and cost are improved, but cycling stability deteriorates
Solution Approach 1:
The patent applies composite materials by combining high-nickel layered material with a coating layer containing rare earth elements and/or refractory metal elements. This composite structure allows the core high-nickel material to provide high capacity while the coating layer provides structural stability and resistance to degradation during cycling, thus resolving the contradiction between high capacity and poor cycling stability
Solution Approach 2:
The patent changes the chemical composition parameters of the positive electrode material by introducing rare earth elements (such as La, Ce, Pr, Nd) and/or refractory metal elements (such as Ti, Zr, Nb, Mo, W) into the material structure. These parameter changes modify the material's properties to enhance cycling stability while maintaining high capacity, directly addressing the technical contradiction
2Ease of manufacture
If high-nickel layered material is used as positive electrode material, then cost is reduced, but cycling stability deteriorates
Solution Approach 1:
The patent uses a composite material strategy where a thin coating layer of rare earth and/or refractory metal elements is applied to the high-nickel material surface. This approach maintains the cost advantage of high-nickel material while adding only a small amount of expensive elements in the coating layer to achieve the required cycling stability
Solution Approach 2:
The patent optimizes the concentration parameters of modifying elements in the coating layer to achieve the minimum effective amount needed for improving cycling stability. By controlling the content of rare earth elements and/or refractory metal elements at optimized levels, the patent reduces material costs while still achieving the desired reliability improvement
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 modification enhances the cycling stability and structural integrity of high-nickel ternary particles, leading to improved cycle life and storage performance.
Implementation Method 1
Rare earth metal atoms (which may be referred to as element A in the following) can enter the surface structure of the positive electrode material to form a fast ion conductive network rich in element A on the surface of high-nickel ternary particles, isolating the electrolyte and reducing side reactions
Implementation Method 2
The refractory metal element (which may be referred to as element B in the following) can enter the high-nickel positive electrode bulk phase and form a stable structure with high bond energy, reducing undesirable phases formed such as rock salt phase under high voltage
Data Source
AI summary
A positive electrode material, a preparation method thereof, a positive electrode plate, a secondary battery, and an electric apparatus. The positive electrode material includes positive electrode material particles. The positive electrode material particle includes a matrix and a modifying element, where the matrix includes LiNixCoyMnzO2, where x≥0.8, y≤0.12, and x+y+z=1. The modifying element includes a rare earth element and/or a refractory metal element.