Composite Cathode Composition for Stable High-Energy Lithium-Air Batteries
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Solution Overview
Problem
Lithium-air or lithium-oxygen batteries face issues with low energy density, high material costs, limited electrochemical reversibility, short cycle life, and risks of thermal runaway due to oxygen desorption and irreversible byproducts.
Innovation Solution
The development of a cathode with a specific composition involving a first and second cathode active material, where the solubility ratio in the electrolytic solvent is less than 0.5, and a method of manufacturing involving a hygroscopic species and reactive oxygen species, resulting in a cathode active material that suppresses oxygen evolution and enhances electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium-air or lithium-oxygen batteries are used to achieve high energy density, then energy density is improved, but oxygen desorption occurs at low temperatures causing thermal runaway and reduced reliability
Solution Approach 1:
A coating layer comprising at least one of a metal oxide, metal hydroxide, metal carbonate, or metal oxyhalide is applied to the cathode active material particles. This coating layer acts as an intermediary barrier that prevents direct interaction between the cathode active material and electrolyte, thereby suppressing oxygen desorption and thermal runaway while maintaining high energy density performance
Solution Approach 2:
The invention changes the surface chemical composition and structure parameters of the cathode active material by applying a protective coating layer. This modifies the surface properties to reduce reactivity with electrolyte and suppress oxygen evolution, enabling safe operation at high energy density without thermal runaway
2Use of energy by moving object
If lithium-air or lithium-oxygen batteries are used to achieve high energy density, then energy density is improved, but electrochemical reversibility is poor due to irreversible byproducts
Solution Approach 1:
The coating layer serves as a protective intermediary that prevents formation of irreversible byproducts by blocking direct chemical reactions between the cathode active material and electrolyte, thereby improving electrochemical reversibility while maintaining high energy density
Solution Approach 2:
The cathode structure is designed as a composite system combining cathode active material particles with a protective coating layer. This composite structure integrates the high energy density benefits of lithium-air chemistry with the stability and reversibility of the coating material, achieving both high energy density and improved electrochemical reversibility
3Ease of manufacture
If conventional cathode materials are used to simplify manufacturing, then manufacturing complexity is reduced, but energy density and performance are limited
Solution Approach 1:
The cathode is structured as an assembly of discrete particles, each comprising a cathode active material core with a protective coating shell. This segmented particle structure enables simplified manufacturing through conventional mixing and coating processes while achieving high energy density at the battery level
Solution Approach 2:
The invention employs composite cathode materials combining active lithium compounds with protective coating layers. These composite particles can be manufactured using extended conventional processes, balancing manufacturing simplicity with enhanced energy density and stability 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 solution achieves high energy density, prolonged cycle life, reduced risk of fire and explosion, and improved rechargeability, with minimal oxygen evolution during operation, enabling efficient battery performance at room temperature.
Implementation Method 1
a ratio of the solubility of the first cathode active material in the electrolytic solvent to the solubility of the second cathode active material in the electrolytic solvent is less than 0.5
Implementation Method 2
resistance to oxygen generation during use
Data Source
AI summary
Batteries that include an electrolyte, having an electrolytic solvent, and a cathode, the cathode including a first cathode active material in contact with a second cathode active material, and where a ratio of the solubility of the first cathode active material in the electrolytic solvent to the solubility of the second cathode active material in the electrolytic solvent is less than 0.5. The batteries can be economically packed and can provide high energy density.