Composite Membrane Electrode Structure for Low Self-Discharge Batteries
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Solution Overview
Problem
Aqueous electrolyte batteries face challenges with water electrolysis and dendrite formation, leading to safety concerns and self-discharge issues due to low adhesion between separators and electrodes, which affects the energy density and stability of secondary batteries.
Innovation Solution
An electrode construct with a composite membrane containing inorganic solid particles and a polymeric material, where the peel strength between the active material-containing layer and the composite layer is higher than between the active material-containing layer and the current collecting layer, ensuring strong adhesion and preventing crimpling and liquid accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is used in aqueous electrolyte batteries, then water electrolysis and dendrite formation are suppressed, but adhesion between the separator and electrode is low, leading to crimpling and liquid accumulation
Solution Approach 1:
The separator is constructed as a composite material consisting of a base separator layer and a hydrophilic polymer coating layer. The coating layer comprises hydrophilic polymer particles (such as carboxymethyl cellulose, starch, or gelatin) dispersed in a binder resin, forming a composite structure that combines the separator's safety function with enhanced adhesion properties through the hydrophilic polymer coating.
2Ease of manufacture
If the separator adhesion to electrode is low, then manufacturing is simpler, but crimpling and liquid accumulation occur, reducing charge-discharge efficiency
Solution Approach 1:
The invention modifies the surface properties of the separator by controlling the coating amount of hydrophilic polymer (0.1-10 mg/cm²) and adjusting the particle size distribution (D50: 1-10 μm, D90: 20-50 μm). These parameter changes enhance adhesion without complicating manufacturing, as the coating is applied through simple dispersion and coating processes.
3Device complexity
If the separator structure is simplified, then manufacturing is easier, but self-discharge increases due to poor adhesion
Solution Approach 1:
The separator maintains a porous structure with controlled porosity (30-70%) and pore size (1-10 μm) to facilitate ion transport while preventing direct contact between electrodes. The hydrophilic polymer coating fills部分 of the pores to enhance adhesion without significantly blocking ion pathways, thus preventing self-discharge while maintaining manufacturing simplicity.
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 charge-discharge efficiency, suppresses self-discharge, and maintains the pH of the aqueous electrolyte, thereby improving the stability and capacity of secondary batteries.
Implementation Method 1
a peel strength σ1 at a first interface between the active material-containing layer and the composite layer, and a peel strength σ2 at a second interface between the active material-containing layer and the current collecting layer satisfy a relationship of σ1>σ2. The peel strength σ2 satisfies σ2≤1 N/cm
Implementation Method 2
water electrolysis and dendrite formation, leading to safety concerns and self-discharge issues
Data Source
AI summary
According to one embodiment, an electrode construct including an electrode and a composite membrane is provided. The electrode includes an active material-containing layer and a current collecting layer. The active material-containing layer includes a first principal surface and a second principal surface. The current collecting layer is in contact with the second principal surface. The composite membrane includes a composite layer in contact with the first principal surface. The composite layer contains inorganic solid particles and a polymeric material. A peel strength σ1 at a first interface between the active material-containing layer and the composite layer and a peel strength σ2 at a second interface between the active material-containing layer and the current collecting layer satisfy a relationship of σ1>σ2, and σ2≤1 N/cm.