Lithium Air Battery Composite Cathode Electrolyte Optimization
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Solution Overview
Problem
Lithium air batteries face challenges in reducing the amount of electrolyte in the cathode, which affects their energy density and manufacturing feasibility due to limitations in the cathode preparation process.
Innovation Solution
A lithium air battery with a composite cathode comprising a porous material and a first electrolyte, where the weight ratio of the porous material to the electrolyte is less than 1:3, and an oxygen blocking layer is introduced to optimize the electrolyte content, reducing it to less than 75 weight percent, thereby improving charging/discharging characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large amount of electrolyte is used to fill pores of the cathode, then the cathode preparation is easier, but the weight of the whole battery increases and energy density decreases
Solution Approach 1:
The patent changes the electrolyte content parameter from conventional high amounts (typically 80-90 wt%) to a reduced amount (less than 75 wt%, preferably 5-70 wt%). This parameter change resolves the contradiction by achieving both easier cathode preparation (maintaining sufficient electrolyte for ion conduction) and reduced battery weight (lower electrolyte content), thereby improving energy density.
2Ease of manufacture
If a large amount of electrolyte is used to fill pores of the cathode, then the cathode preparation is easier, but the energy density of the lithium air battery significantly decreases
Solution Approach 1:
The patent optimizes the electrolyte content parameter to be less than 75 wt% (preferably 5-70 wt%) of the total cathode weight. This parameter optimization resolves the contradiction by maintaining sufficient electrolyte for proper cathode preparation and ion conduction while significantly reducing the weight penalty, thereby improving energy density from theoretical 3,500 Wh/kg to practical achievable levels.
3Use of energy by moving object
If the electrolyte content is reduced, then the energy density improves, but the cathode preparation becomes more difficult
Solution Approach 1:
The patent identifies an optimal electrolyte content range of 5-70 wt% (of total cathode weight) that balances both requirements. Within this parameter range, the cathode maintains sufficient electrolyte for proper preparation and ion conduction while achieving reduced weight for improved energy density. This resolves the contradiction by finding the optimal parameter window.
Solution Approach 2:
The patent creates a composite cathode structure combining porous material (carbon-based materials with specific pore structures) and electrolyte in optimized ratios. This composite approach allows reduced electrolyte content (improving energy density) while the porous material structure provides the necessary framework for ion conduction and electrochemical reactions, making cathode preparation feasible.
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 optimized electrolyte content enhances the battery's capacity retention rate and energy density, improving the lithium air battery's lifespan and manufacturing efficiency by minimizing electrolyte squeeze-out and maintaining high performance.
Implementation Method 1
a composite cathode including a porous material and a first electrolyte, wherein a weight ratio of the porous material to the first electrolyte is less than 1:3
Implementation Method 2
an anode capable of incorporating and deincorporating lithium ions
Data Source
AI summary
A lithium air battery includes: a composite cathode including a porous material and a first electrolyte; an anode including lithium metal, and an oxygen blocking layer disposed between the composite cathode and the anode, wherein a weight ratio of the porous material and the first electrolyte in the composite cathode is less than about 1:3. Also a method of manufacturing the lithium air battery.