Composite Positive Electrode Layers for High-Voltage Battery Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high average voltage, and excellent lifetime while maintaining economic viability.
Innovation Solution
A positive electrode active material comprising a combination of olivine-structured and layered-structured lithium compounds, with specific elemental compositions and particle sizes, is used to enhance energy density and voltage while improving structural stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single positive electrode active material is used, then the electrode structure is simple and manufacturing is easier, but energy density and voltage performance are limited
Solution Approach 1:
The patent combines two different positive electrode active materials with distinct crystal structures (olivine and layered) into a single composite electrode. The olivine-based material (LiFe0.4Mn0.5Ti0.1PO4) provides structural stability and safety, while the layered-based material (LiNi0.8Co0.1Mn0.1O2) delivers high capacity and voltage. This merging of materials with complementary properties resolves the contradiction by achieving high energy density without excessive structural complexity.
Solution Approach 2:
The patent employs a composite material system consisting of olivine-based lithium iron manganese titanium phosphate and layered lithium nickel cobalt manganese oxide. This composite structure leverages the advantages of both material types: the olivine phase contributes to thermal stability and long cycle life, while the layered phase provides high specific capacity. The composite approach enables simultaneous optimization of energy density, voltage, and structural stability.
2Quantity of substance
If high nickel content layered material is used to increase energy density, then voltage and capacity improve, but structural stability and lifetime deteriorate
Solution Approach 1:
The patent applies local quality by creating a heterogeneous electrode structure where different regions contain materials with specialized functions. The layered LiNi0.8Co0.1Mn0.1O2 particles (with high nickel content for high capacity) are distributed among olivine-based LiFe0.4Mn0.5Ti0.1PO4 particles (with high structural stability). This spatial distribution of different material properties allows the high-nickel layered material to deliver energy density while the olivine material provides structural support and stability throughout the electrode.
Solution Approach 2:
The composite material system specifically addresses the stability issue of high-nickel layered materials by combining them with olivine-based material. The olivine phase acts as a structural buffer that maintains electrode integrity during cycling, preventing the structural degradation that would otherwise occur with high-nickel content. This composite approach enables the use of high-capacity layered material while maintaining long-term structural stability and extended battery lifetime.
3Reliability
If olivine-based material with high structural stability is used, then lifetime and safety improve, but energy density and average voltage decrease
Solution Approach 1:
The patent merges olivine-based material (LiFe0.4Mn0.5Ti0.1PO4) known for structural stability with layered-based material (LiNi0.8Co0.1Mn0.1O2) known for high energy density. The olivine component ensures long cycle life and thermal stability, while the layered component contributes high capacity and voltage. By combining these materials in a composite electrode structure, the patent achieves both extended lifetime and high energy density simultaneously.
Solution Approach 2:
The patent optimizes the compositional parameters of both materials to achieve the desired balance. The olivine-based material uses specific doping ratios (Fe0.4Mn0.5Ti0.1) to maximize structural stability while maintaining acceptable capacity. The layered material uses high nickel content (0.8) to maximize energy density. The overall electrode composition and particle size distribution are also optimized parameters that enable both high energy density and long lifetime performance.
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 electrode material achieves high energy density, high average voltage, and extended battery life, thereby enhancing the performance and efficiency of rechargeable lithium batteries.
Implementation Method 1
a positive electrode and a negative electrode, each including an active material that allows intercalation and deintercalation of lithium ions
Implementation Method 2
produce electrical energy from redox reactions that take place as lithium ions are intercalated into or deintercalated from the positive electrode and the negative electrode
Data Source
AI summary
Provided are a positive electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same, and for example, a positive electrode for a rechargeable lithium battery, including a current collector, a first positive electrode active material layer on the current collector, and a second positive electrode active material layer on the first positive electrode active material layer. The first positive electrode active material layer includes a first particle having an olivine structure, and a second particle having a layered structure, and the second positive electrode active material layer includes a third particle having an olivine structure. The first particle is a single particle, the third particle is in the form of a secondary particle in which a plurality of third primary particles are aggregated, and the second particle has a greater average particle diameter than each of the first particle and the third particle.