Lithium Battery Positive Electrode Agglomeration for Thermal Stability
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Solution Overview
Problem
Conventional positive electrode active materials for lithium batteries suffer from unsatisfactory residual capacity, recovery capacity, and thermal stability, particularly due to the high cost and unreliable supply of LiCoO2, as well as the limitations of existing alternatives.
Innovation Solution
A positive electrode active material comprising secondary particles formed from agglomerated primary lithium composite oxide particles with an amorphous material, such as lithium sulfate, heat-treated between 700°C to 950°C, which reduces the specific surface area exposed to the electrolyte, enhancing thermal stability and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LiCoO2 is used as positive electrode active material, then high capacity is achieved, but cost increases and supply reliability decreases
Solution Approach 1:
The patent replaces expensive LiCoO2 with cheaper lithium nickelate (LiNiO3) as the positive electrode active material. This substitution maintains functional performance while significantly reducing cost and supply chain dependency on cobalt, directly addressing the technical contradiction between capacity and supply reliability.
2Ease of manufacture
If conventional positive electrode active materials are used, then manufacturing is simple, but residual capacity and thermal stability are unsatisfactory
Solution Approach 1:
The patent employs a two-stage heat treatment process with specific temperature ranges (first heat treatment at 800-950°C, second heat treatment at 500-700°C) to transform the crystal structure and surface properties of lithium nickelate. This parameter-controlled approach achieves high thermal stability and residual capacity while maintaining manufacturing feasibility, resolving the contradiction between ease of manufacture and thermal stability.
3Quantity of substance
If specific surface area is increased, then capacity is improved, but thermal stability decreases
Solution Approach 1:
The patent creates a heterogeneous structure where the interior particles maintain high surface area for capacity, while the exterior surface undergoes specific heat treatment modifications to enhance thermal stability. The two-stage heat treatment creates different local properties: the first stage forms the bulk structure, while the second stage modifies the surface layer to resist thermal degradation, thus resolving the contradiction between capacity and thermal stability.
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 proposed solution achieves high residual and recovery capacities at elevated temperatures while maintaining thermal stability, outperforming conventional materials in lithium batteries.
Implementation Method 1
heat treating the resultant at a temperature from greater than about 700° C. to about 950° C. or less
Implementation Method 2
When lithium ions are absorbed or desorbed, an oxidation reaction and a reduction reaction occur, respectively, and due to the oxidation reaction and the reduction reaction, electric energy is generated
Implementation Method 3
When lithium ions are absorbed or desorbed, an oxidation reaction and a reduction reaction occur, respectively
Implementation Method 4
When lithium ions are absorbed or desorbed, an oxidation reaction and a reduction reaction occur, respectively
Data Source
AI summary
A positive electrode active material for lithium batteries includes secondary particles having primary particles and an amorphous material. A method of manufacturing the positive electrode active material includes mixing a lithium composite oxide and a lithium salt, and heat treating the mixture. A positive electrode includes the positive electrode active material, and a lithium battery includes the positive electrode.