Aqueous Secondary Battery Electrolyte for Proton Exchange Suppression
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Solution Overview
Problem
Existing lithium secondary batteries using nonaqueous organic solvents face safety concerns due to flammability, high production costs due to dry environment requirements, and increased internal resistance due to low electrical conductivity of the electrolyte solution.
Innovation Solution
A secondary battery design utilizing a first aqueous electrolyte with a pH greater than 7, which suppresses proton exchange and oxygen generation, combined with a lithium-containing compound as the positive electrode active material with an average operating potential less than 4.0 V, to enhance cycle life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a nonaqueous organic solvent is used as the electrolyte solution, then high electromotive force (2V to 4.5V) and oxidation resistance are achieved, but safety deteriorates due to flammability
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte from nonaqueous organic solvent to aqueous solution, fundamentally altering the chemical composition while maintaining battery functionality. This parameter change eliminates flammability while enabling the use of lithium-containing compounds with operating potentials below 4.0V vs. Li/Li+
Solution Approach 2:
The patent converts the typically harmful proton exchange reaction into a beneficial mechanism by selecting specific lithium-containing compounds (operating potential < 4.0V) that are resistant to proton exchange. This transforms what was previously a degradation mechanism into a stable operating condition for aqueous batteries
2Stability of the object's composition
If a nonaqueous organic solvent is used as the electrolyte solution, then oxidation resistance is improved, but production cost increases due to dry environment requirements
Solution Approach 1:
The patent changes the electrolyte composition parameter from nonaqueous to aqueous, which fundamentally alters the manufacturing environment requirements. Aqueous electrolytes allow production in normal atmospheric conditions, eliminating the need for costly dry room facilities while maintaining sufficient oxidation resistance through proper electrode material selection
3Power
If a nonaqueous organic solvent is used as the electrolyte solution, then electromotive force is improved, but internal resistance increases due to low electrical conductivity
Solution Approach 1:
The patent changes the electrolyte's electrical conductivity parameter by using aqueous solution, which inherently has higher ionic conductivity than nonaqueous organic solvents. This parameter change directly reduces internal resistance while the selection of lithium-containing compounds with operating potentials below 4.0V maintains adequate electromotive force
4Reliability
If the electrolyte is converted to aqueous solution, then safety and production cost are improved, but capacity decreases due to proton exchange reaction
Solution Approach 1:
The patent changes the electrochemical stability window parameter by selecting lithium-containing compounds with operating potentials specifically below 4.0V vs. Li/Li+. This parameter selection ensures the electrode material operates in a potential range where proton exchange is minimized, thereby preserving capacity while using safe aqueous electrolyte
Solution Approach 2:
The patent converts the typically harmful proton exchange reaction into a non-issue by selecting electrode materials that are inherently resistant to proton exchange. This transforms the aqueous electrolyte's potential weakness into a stable operating condition, maintaining capacity while achieving safety
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 battery design achieves excellent cycle life characteristics by suppressing proton exchange and oxygen generation, thereby maintaining high discharge capacity and reducing the risk of safety issues associated with nonaqueous batteries.
Implementation Method 1
a first aqueous electrolyte held in at least the positive electrode. pH of the first aqueous electrolyte is more than 7. In the secondary battery, proton exchange for the positive electrode active material is suppressed
Implementation Method 2
pH of the first aqueous electrolyte is more than 7. In the secondary battery, proton exchange for the positive electrode active material is suppressed, and in addition, generation of oxygen in the positive electrodes is suppressed
Implementation Method 3
The positive electrode active material contains a lithium-containing compound that exhibits an average operating potential of less than 4.0 V based on lithium metal
Data Source
AI summary
A secondary battery that includes: a positive electrode containing a positive electrode active material; a negative electrode; a separator arranged between the positive electrode and the negative electrode; and a first aqueous electrolyte held in at least the positive electrode. pH of the first aqueous electrolyte is more than 7. The positive electrode active material contains a lithium-containing compound that exhibits an average operating potential of less than 4.0 V based on lithium metal.