Porous Inorganic Separator for Aqueous Battery Electrolysis Control
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Solution Overview
Problem
Nonaqueous electrolyte batteries face safety concerns due to combustible solvents, while aqueous electrolyte batteries suffer from low charge/discharge efficiency due to water electrolysis, particularly at the negative electrode during initial charge.
Innovation Solution
A separator comprising an inorganic particle layer with a polymeric binder and fiber substance is positioned between the negative and positive electrodes, allowing alkali metal ions to pass while restricting aqueous solvent movement, maintaining pH and preventing water electrolysis, thus enhancing charge/discharge efficiency and battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nonaqueous electrolyte is used, then charge/discharge efficiency and electromotive force are improved, but safety deteriorates due to combustible solvent
Solution Approach 1:
A separator comprising an inorganic particle layer is introduced as an intermediary component between the negative and positive electrodes. The inorganic particle layer acts as a mediator that restricts the movement of combustible nonaqueous electrolyte while maintaining ion conductivity, thereby preventing internal short circuits and improving safety without compromising charge/discharge efficiency
Solution Approach 2:
The separator is constructed as a composite material consisting of inorganic particles (such as alumina, silica, or boehmite) combined with a polymeric binder. This composite structure provides both mechanical integrity and functional properties: the inorganic particles form a porous network that physically restricts electrolyte movement while allowing ion transport, and the polymeric binder holds the structure together, creating a safe yet efficient barrier
2Reliability
If aqueous electrolyte is used, then safety is improved due to non-combustible solvent, but charge/discharge efficiency deteriorates due to water electrolysis
Solution Approach 1:
The separator's physical and chemical parameters are optimized to create a selective barrier. The pore size, surface area, and hydrophobicity of the inorganic particle layer are controlled to allow efficient ion transport while restricting water movement. By changing these parameters, the separator enables aqueous electrolyte systems to achieve high charge/discharge efficiency comparable to nonaqueous systems while maintaining the safety advantage of using water-based electrolytes
3Stability of the object's composition
If separator restricts solvent movement, then pH stability and prevention of water electrolysis are improved, but ion conductivity may deteriorate
Solution Approach 1:
The inorganic particle layer is designed with a controlled porous structure where the pore size is smaller than the diameter of solvent molecules but larger than dehydrated ions. This porous configuration allows dehydrated ions to pass through freely while restricting bulk solvent movement, thereby maintaining both high ion conductivity and pH stability. The porosity enables selective transport based on molecular size differences
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 separator effectively suppresses water electrolysis at the negative electrode, improving charge/discharge efficiency and extending battery life by maintaining a high pH and reducing internal resistance, while also preventing short circuits and increasing energy density.
Implementation Method 1
a separator comprising an inorganic particle layer with a polymeric binder and fiber substance, in which a mass ratio of the fiber substance with respect to a total mass of the inorganic particles, the polymeric binder, and the fiber substance is 0.1 mass % or more and 40 mass % or less
Implementation Method 2
maintaining pH and preventing water electrolysis, thus enhancing charge/discharge efficiency and battery life
Data Source
AI summary
A separator includes an inorganic particle layer including an inorganic particle, a polymeric binder and a fiber substance. A mass ratio of the fiber substance with respect to a total mass of the inorganic particle, the polymeric binder and the fiber substance is 0.1 mass % or more and 40 mass % or less.