Low Counter-Ion Permeability Layer for Battery Concentration Polarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional batteries face a tradeoff between energy density and charge/discharge rate due to concentration polarization, where counter-ions accumulate or deplete near electrodes, reducing performance and potentially causing damage.
Innovation Solution
Incorporating a low counter-ion permeability layer between the separator and positive electrode in battery cells, using materials like LATP, LLZO, or LiPON, to impede counter-ion movement and maintain ion concentration, thereby reducing concentration polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of active material in the electrodes is increased by decreasing the pore space occupied by the electrolyte or increasing the thickness of the electrode, then the energy density of the battery is improved, but the charge/discharge rate decreases
Solution Approach 1:
The invention divides the electrolyte space into two distinct regions: a first electrolyte region adjacent to the positive electrode and a second electrolyte region adjacent to the negative electrode, separated by a low counter-ion permeability layer. This segmentation allows each region to be optimized independently for its respective electrode's charge/discharge characteristics, enabling high energy density while maintaining high charge/discharge rates.
Solution Approach 2:
The low counter-ion permeability layer acts as an intermediary barrier between the two electrolyte regions. It selectively restricts counter-ion transport while allowing active ions to pass, thereby preventing harmful concentration polarization effects and enabling both high energy density and high charge/discharge rate performance simultaneously.
2Productivity
If conventional batteries attempt to reduce concentration polarization by increasing the mobility of the reactive ions, then the charge/discharge speed is improved, but the electrolyte redesign increases cost and reduces efficiency in other ways
Solution Approach 1:
Instead of modifying the entire electrolyte composition to increase ion mobility, the invention introduces a low counter-ion permeability layer as an intermediary component. This layer selectively manages counter-ion transport without requiring comprehensive electrolyte redesign, thereby improving charge/discharge speed while maintaining electrolyte simplicity and efficiency.
Solution Approach 2:
The invention applies a specific functional property (low counter-ion permeability) to a localized region (the layer between electrolyte regions) rather than modifying the entire electrolyte system. This allows targeted control of counter-ion transport to reduce concentration polarization without compromising overall electrolyte performance or incurring extensive redesign costs.
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
This configuration enhances charging and discharging speeds and capacities by maintaining steady ion concentrations, reducing undesirable reactions, and allowing for different counter-ions and solvents at each electrode, leading to improved battery efficiency and stability.
Implementation Method 1
a low counter-ion permeability layer interposed between the separator and the positive electrode. The separator has a first permeability to counter-ions, which do not participate in the battery electrode reactions, and the low counter-ion permeability layer has a second permeability to the counter-ions that is less than the first permeability
Implementation Method 2
positive ions, for example lithium ions in a lithium-ion battery, travel within the battery from the negative electrode, through an electrolyte, to the positive electrode
Implementation Method 3
The counter-ions, or the ions that do not participate in the reactions at the negative electrode and positive electrode, tend to migrate in the direction opposite of the direction the active ions are moving
Data Source
AI summary
An electrode configuration for a battery cell includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a low counter-ion permeability layer interposed between the separator and the positive electrode. The separator has a first permeability to counter-ions, which do not participate in the battery electrode reactions, and the low counter-ion permeability layer has a second permeability to the counter-ions that is less than the first permeability. The separator includes a first salt concentration adjacent to the low counter-ion permeability layer and a second salt concentration adjacent to the negative electrode, and the second salt concentration is greater than the first salt concentration.