Lithium-Oxygen Coating for Cathode Materials With Stable Discharge Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing batteries face challenges in maintaining high discharge voltage due to increased interfacial resistance and oxidized layer formation at the positive-electrode active material and solid electrolyte interface.
Innovation Solution
A positive-electrode material is developed with a coating layer containing oxygen and lithium, maintaining a Li/O atomic ratio of 0.26 or less, which improves the potential stability of the coating layer and reduces interfacial resistance, thereby enhancing discharge voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the positive-electrode active material, then potential stability is improved and interfacial resistance is reduced, but the discharge voltage decreases due to oxidized layer formation
Solution Approach 1:
The patent changes the compositional parameters of the coating layer by strictly controlling the Li/O atomic ratio to be 0.26 or less, and specifying the content of alkali salts (0.1-10 wt%) and oxide materials. This parameter optimization resolves the contradiction by achieving both potential stability and high discharge voltage simultaneously
Solution Approach 2:
The coating layer is designed as a composite material containing both alkali salts and oxide materials in specific proportions. This composite structure provides both the potential stability from the oxide material and the ionic conductivity from the alkali salt, while the controlled Li/O ratio prevents oxidized layer formation that would reduce discharge voltage
2Reliability
If the Li/O ratio in the coating layer is increased, then ionic conductivity is improved, but oxidized layer formation increases and discharge voltage decreases
Solution Approach 1:
The patent establishes an optimal parameter range for the Li/O atomic ratio (0.26 or less) that balances ionic conductivity with prevention of oxidized layer formation. This precise parameter control allows the coating to maintain low interfacial resistance without generating harmful oxidation products that would reduce discharge voltage
3Use of energy by moving object
If alkali salt content in the coating layer is increased, then discharge voltage is improved, but thermal stability decreases
Solution Approach 1:
The coating layer combines alkali salts with oxide materials in a composite structure where the oxide component provides thermal stability while the alkali salt contributes to ionic conductivity and discharge voltage. The specific composition range (0.1-10 wt% alkali salt with controlled Li/O ratio) optimizes this balance between electrical performance and thermal stability
Data Source
AI summary
A positive-electrode material according to the present disclosure includes a positive-electrode active material and a coating layer covering the positive-electrode active material, wherein the coating layer contains oxygen and lithium, the positive-electrode active material and the coating layer constitute a coated active material, and the ratio Li/O of the lithium content to the oxygen content in a surface layer portion of the coated active material is 0.26 or less based on the atomic ratio.