Lithium-Rich Composite Cathode for High Energy Density Batteries
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Solution Overview
Problem
Lithium ion batteries face limitations in energy density and cycling performance due to high irreversible capacity loss and limited utilization of theoretical capacity, particularly in high power applications.
Innovation Solution
Development of specific ranges of metal oxide compositions, such as Li1+bNiαMnβCoγO2-zFz, with optional metal and fluorine dopants, integrated in a layer-layer superlattice structure, and coatings like MgO or AlF3 to enhance specific capacity, cycling performance, and reduce irreversible capacity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional cathode materials like LiCoO2 are used, then the battery can deliver high current for high power applications, but the energy density is reduced and only roughly 50% of theoretical capacity can be utilized
Solution Approach 1:
The patent employs composite cathode materials combining LiCoO2, LiMn2O4, and LiFePO4 in specific ratios, along with surface coating materials, to achieve both high power delivery and high energy density. The composite structure allows each material to contribute its strengths while mitigating individual weaknesses.
Solution Approach 2:
The patent optimizes the stoichiometric ratios of metal elements (Co, Mn, Fe, Ni) and controls particle size distribution to enhance both power delivery capability and energy density. By adjusting composition parameters and structural characteristics, the cathode material achieves improved utilization of theoretical capacity.
2Adaptability or versatility
If LiMn2O4 or LiFePO4 are used as cathode materials, then alternative to LiCoO2 is provided, but no significant improvement in energy density is achieved
Solution Approach 1:
The patent merges multiple cathode materials (LiCoO2, LiMn2O4, LiFePO4) into a composite structure, combining their advantages to achieve both material versatility and enhanced energy density that neither material can achieve alone.
Solution Approach 2:
The composite cathode material integrates different lithium-based compounds with complementary properties, creating a synergistic effect that surpasses the energy density of individual materials while maintaining adaptability.
3Power
If high power battery design is implemented, then high current delivery is achieved, but total energy that can be delivered is reduced
Solution Approach 1:
The patent adjusts key parameters including the ratio of high-voltage to low-voltage materials, particle size distribution, and surface area-to-volume ratio to optimize the balance between power delivery and total energy capacity.
Solution Approach 2:
The composite structure enables the battery to deliver both high current (from LiCoO2 component) and high total energy (from LiFePO4 and LiMn2O4 components), resolving the trade-off between power and energy.
4Use of energy by moving object
If high energy battery design is implemented, then higher total capacity is achieved, but the battery is lower in power for high current applications
Solution Approach 1:
The patent combines high-capacity materials (LiFePO4, LiMn2O4) with high-power materials (LiCoO2) in a composite structure, enabling the battery to deliver both high total capacity and high current capability simultaneously.
Solution Approach 2:
The composite cathode material integrates materials with complementary power and energy characteristics, creating a synergistic effect that achieves both high total capacity and high power delivery capability.
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 improved balance of high specific capacity, low DC-resistance, and excellent cycling performance, suitable for high energy applications like electric vehicles, with reduced irreversible capacity loss and increased energy and power density.
Implementation Method 1
a positive electrode active material that can intercalate and deintercalate lithium
Implementation Method 2
a positive electrode comprising a lithium-containing composite oxide
Data Source
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AI summary
Lithium rich and manganese rich lithium metal oxides are described that provide for excellent performance in lithium-based batteries. The specific compositions can be engineered within a specified range of compositions to provide desired performance characteristics. Selected compositions can provide high values of specific capacity with a reasonably high average voltage. Compositions of particular interest can be represented by the formula, x Li2MnO3 ° (1-x) Li Niu+?Mnu-?CowAyO2. The compositions undergo significant first cycle irreversible changes, but the compositions cycle stably after the first cycle.