Positive Electrode Material Composition for High-Voltage Li Batteries
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, and improved low-temperature characteristics.
Innovation Solution
A positive electrode active material comprising a compound represented by Formula 1, with specific compositional ranges, is used, along with a conductive material and binder, to form a positive electrode layer, enhancing conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity positive electrode materials are used to increase energy density, then the battery capacity increases, but the operating voltage decreases and low-temperature performance deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode material by controlling the molar ratios of Fe, Mn, and Ti elements, as well as the particle size parameters. Specifically, it uses materials with Fe:Mn:molar ratio of 0.8-1.2:0.1-0.3:0.001-0.05 and particle diameter of 3-10 μm, which changes the material properties to achieve high capacity while maintaining low-temperature performance and operating voltage.
Solution Approach 2:
The patent creates a composite positive electrode material by combining multiple elements (Fe, Mn, Ti) in specific ratios to form a multi-element compound. This composite structure leverages the advantages of each element: Fe provides high capacity, Mn improves voltage stability, and Ti enhances low-temperature performance, thereby resolving the contradiction between capacity and temperature performance.
2Power
If the positive electrode material composition is optimized for high voltage, then operating voltage increases, but energy density and low-temperature characteristics deteriorate
Solution Approach 1:
The patent optimizes the compositional parameters by precisely controlling the molar ratios of Fe, Mn, and Ti, as well as the particle size distribution. This parameter optimization allows the material to achieve high operating voltage (3.0-4.5V) while maintaining high energy density through the synergistic effect of the multi-element composition.
3Ease of manufacture
If conventional positive electrode materials are used, then manufacturing is simpler, but energy density, operating voltage, and low-temperature performance are insufficient
Solution Approach 1:
The patent maintains manufacturing simplicity by using conventional solid-state reaction methods while only changing the compositional parameters (element ratios and particle size). This approach avoids complex manufacturing processes while achieving superior energy density and performance characteristics through optimized material composition.
4Quantity of substance
If high-capacity materials are used to increase battery capacity, then the battery can store more energy, but the operating voltage decreases
Solution Approach 1:
The patent employs a composite material strategy by integrating Fe (for capacity), Mn (for voltage stability), and Ti (for structural stability) in a multi-element compound. This composite structure enables the material to simultaneously achieve high capacity and maintain high operating voltage through the synergistic contribution of each element.
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 results in a rechargeable lithium battery with improved energy density, operating voltage, and low-temperature performance, while preventing manganese dissolution and facilitating easier electrode processing.
Implementation Method 1
Electrical energy is produced by oxidation and reduction reactions when the lithium ions are intercalated into and deintercalated from the positive electrode and the negative electrode.
Data Source
AI summary
A positive electrode active material for a rechargeable lithium battery, a positive electrode containing the same, and a rechargeable lithium battery including the same are disclosed. A positive electrode active material includes a first particle containing a compound represented by Formula 1 and having a first average particle diameter:where, in Formula 1, 0.8≤a≤1.2, 0.79≤x≤0.9, 0.1≤y≤0.2, 0.001≤z≤0.05, 0≤b≤0.05, and 0.995≤x+y+z≤1.01.