Dual-Electrolyte Secondary Battery for High-Voltage Stability
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Solution Overview
Problem
Secondary batteries face performance degradation when using high-voltage electrode materials due to electrolyte decomposition in the positive or negative electrodes.
Innovation Solution
A secondary battery design with separate positive and negative electrode electrolytic solutions, using solvents with specific reduction and oxidation potentials to suppress decomposition, and optionally incorporating polymers to gel the solvents, thereby maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-voltage electrode materials are used to increase battery voltage, then battery voltage is improved, but electrolyte decomposition occurs at the electrodes causing performance deterioration
Solution Approach 1:
The patent divides the electrolytic solution into separate positive electrode electrolytic solution and negative electrode electrolytic solution, each optimized for its respective electrode's voltage potential. The positive electrode electrolytic solution uses solvents with high oxidation potential to resist oxidative decomposition, while the negative electrode electrolytic solution uses solvents with low reduction potential to resist reductive decomposition. This segmentation allows each electrolytic solution to be tailored for its specific electrode environment, preventing decomposition even at high voltages.
Solution Approach 2:
The patent applies different solvent compositions locally to each electrode region. The positive electrode electrolytic solution contains solvents specifically selected for their resistance to oxidation at high positive potentials, while the negative electrode electrolytic solution contains solvents selected for their resistance to reduction at negative potentials. This local optimization of electrolyte composition ensures that each electrode operates within its stable voltage window without causing electrolyte decomposition.
2Power
If the electrolytic solution is used in a wide voltage range, then battery voltage is improved, but oxidative decomposition occurs at the positive electrode
Solution Approach 1:
The patent changes the chemical parameters of the electrolytic solution by selecting specific solvents with appropriately high oxidation potentials for the positive electrode electrolytic solution. This parameter optimization allows the electrolyte to remain stable at high positive voltages where conventional electrolytes would undergo oxidative decomposition.
3Power
If the electrolytic solution is used in a wide voltage range, then battery voltage is improved, but reductive decomposition occurs at the negative electrode
Solution Approach 1:
The patent changes the chemical parameters of the electrolytic solution by selecting specific solvents with appropriately low reduction potentials for the negative electrode electrolytic solution. This parameter optimization allows the electrolyte to remain stable at negative voltages where conventional electrolytes would undergo reductive decomposition.
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 design effectively prevents electrolyte decomposition, maintaining battery performance even at increased voltages, enhancing safety through solvent retention.
Implementation Method 1
The second solvent is a solvent having a reduction potential that is lower (less noble) than a potential of negative electrode. By using the second solvent, the reductive decomposition of the electrolytic solution in the negative electrode can be suppressed
Implementation Method 2
The first solvent is a solvent having an oxidation potential that is higher (nobler) than a potential of positive electrode. By using the first solvent, the oxidative decomposition of the electrolytic solution in the positive electrode can be suppressed
Data Source
Figure 1
Figure 2(a)~2(b)
AI summary
Disclosed is a secondary battery comprising: a positive electrode current collector; a negative electrode current collector; a positive electrode electrolytic solution part provided between the positive electrode current collector and the negative electrode current collector so as to be in contact with the positive electrode current collector, the positive electrode electrolytic solution part comprising a positive electrode electrolytic solution; and a negative electrode electrolytic solution part provided between the positive electrode current collector and the negative electrode current collector so as to be in contact with the negative electrode current collector, the negative electrode electrolytic solution part comprising a negative electrode electrolytic solution. The positive electrode electrolytic solution comprises an electrolyte salt and a non-aqueous solvent comprising a first solvent. The negative electrode electrolytic solution comprises an electrolyte salt and a non-aqueous solvent comprising a second solvent. The second solvent is a solvent having a reduction potential that is lower than a potential of the negative electrode.