Layered Cathode Material Doping for Stable High-Energy Battery Cells
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Solution Overview
Problem
The performance of positive electrode materials in battery cells is crucial for the overall performance of the battery, but existing materials face issues with structural stability and energy density due to lithium ion deintercalation, leading to structural collapse and stress-induced cracking.
Innovation Solution
A positive electrode material comprising a layered lithium-containing metal oxide with larger radius cations (L ions) is introduced, which weakens electrostatic repulsion and widens oxygen layer spacing, improving structural stability and reducing the risk of cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium ion deintercalation is performed to increase energy density, then the energy density of the battery cell is improved, but the structural stability deteriorates leading to structural collapse and stress-induced cracking
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode material by introducing larger radius cations (L ions) such as Na+, K+, Ca2+, Sr2+, Ba2+, Y3+, or La3+ that occupy lithium sites in the layered structure. This parameter change in ionic radius and charge state fundamentally alters the electrostatic interactions and structural properties, enabling the material to maintain stability during lithium ion deintercalation while preserving high energy density capability
Solution Approach 2:
The patent creates a composite doped structure where larger radius cations are incorporated into the lithium-containing metal oxide lattice. This composite approach combines the high capacity characteristics of lithium-rich layered oxides with the structural stabilizing effects of heteroatom doping, resulting in a material that exhibits both high energy density and enhanced structural stability during cycling
2Quantity of substance
If the amount of nickel is increased to improve capacity, then the energy density is improved, but the structural stability worsens due to layer transition and cracking
Solution Approach 1:
The patent changes the compositional parameters by incorporating larger radius cations that preferentially occupy lithium sites rather than transition metal sites. This parameter change in cation distribution and charge balance allows for high nickel content (0.5 ≤ b ≤ 0.96) while maintaining layered structure stability, as the doped cations provide electrostatic stabilization that prevents Ni-O bond weakening and layer transition
Solution Approach 2:
The larger radius cations act as intermediary stabilizing agents within the layered structure. These cations serve as structural mediators that buffer the inherent instability of high-nickel compositions by providing electrostatic balance and structural support, thereby enabling the material to achieve high capacity without suffering from the typical layer transition and cracking issues associated with high nickel content
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 solution enhances the structural stability and cycling performance of the positive electrode material, allowing for higher energy density and service voltage in battery cells.
Implementation Method 1
L ions, which are cations having a radius larger than a radius of a Li ion, are doped, thereby weakening electrostatic repulsion and widening spacing between oxygen layers
Data Source
AI summary
A positive electrode material, a positive electrode plate, a battery cell, a battery, and an electric apparatus are described. The positive electrode material includes a layered lithium-containing metal oxide, and the layered lithium-containing metal oxide is represented by a general formula LiaLxNibCocMndM(1−b−c−d)OeNf, where an L ion is a cation having a radius larger than a radius of a Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, and N includes at least one of F, S, and P, where 0<a<2, 0≤b<1, 0≤c<1, 0≤d<1, 0<b+c+d≤1, 0<e≤2, 0≤f<2, and 0<x≤0.8. The technical solutions provided in the embodiments of this application help to improve performance of the positive electrode material and performance of the battery cell.