Bipolar Electrodialysis Membrane Thickness for Lithium Hydroxide Yield
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Solution Overview
Problem
Existing electrodialysis methods for producing lithium hydroxide using bipolar membranes suffer from low production amounts and significant energy inefficiencies due to inappropriate ion exchange membrane combinations, leading to decreased lithium hydroxide yield.
Innovation Solution
A bipolar electrodialysis device is designed with specific membrane thicknesses and operational parameters, including anion and cation selective dialysis membranes of 70 to 170 µm and bipolar membranes of 140 to 255 µm, and an applied voltage of 2.5 V or less, to enhance lithium hydroxide production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional electrodialysis methods with bipolar membranes are used to manufacture lithium hydroxide, then the process is environmentally friendly and produces no by-products, but the production amount is low and energy efficiency drops significantly
Solution Approach 1:
The patent optimizes the thickness parameters of ion exchange membranes to resolve the contradiction between environmental friendliness and productivity. Specifically, the anion selective dialysis membrane thickness is set to 70-170 μm and the cation selective dialysis membrane thickness is set to 70-170 μm, which improves ion transport efficiency and lithium hydroxide production amount while maintaining the environmentally friendly electrodialysis process
2Object-generated harmful factors
If conventional electrodialysis methods with bipolar membranes are used, then the process avoids by-product formation, but the production amount of lithium hydroxide is low compared to electrical energy used
Solution Approach 1:
The patent changes the thickness parameters of the ion exchange membranes to improve energy efficiency. The anion selective dialysis membrane is optimized to 70-170 μm and the cation selective dialysis membrane to 70-170 μm, which reduces electrical resistance and improves current efficiency, thereby reducing energy loss while maintaining by-product-free operation
Solution Approach 2:
The patent uses a composite membrane structure combining bipolar membranes with ion selective dialysis membranes in a multi-layer configuration. This composite structure improves overall membrane performance and energy efficiency while maintaining the environmental benefits of bipolar membrane electrodialysis
3Device complexity
If inappropriate ion exchange membrane combination is used in electrodialysis device, then the device structure is simpler, but the production amount of lithium hydroxide is low and energy efficiency drops
Solution Approach 1:
The patent optimizes the thickness parameters of each membrane layer to improve productivity without significantly increasing device complexity. The anion selective dialysis membrane thickness of 70-170 μm and cation selective dialysis membrane thickness of 70-170 μm are carefully selected to balance structural simplicity with high lithium hydroxide production efficiency
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 device achieves a lithium hydroxide production current efficiency of 50% or more, with improved energy efficiency and economic feasibility through optimized membrane properties and process conditions.
Implementation Method 1
a bipolar electrodialysis device using a bipolar membrane... anion selective dialysis membrane... cation selective dialysis membrane
Implementation Method 2
separate specific ions using current... applying voltage to the bipolar electrodialysis device
Implementation Method 3
produce acid and alkaline solutions without occurrence of by-products... forming an acidic aqueous solution... forming a lithium hydroxide aqueous solution
Data Source
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AI summary
The present invention relates to a bipolar electrodialysis device for manufacturing lithium hydroxide, having a structure in which a positive electrode cell including a positive electrode, a first bipolar membrane, an anion selective dialysis membrane, a cation selective dialysis membrane, a second bipolar membrane, and a negative electrode cell including a negative electrode are sequentially arranged, wherein the anion selective dialysis membrane has a thickness of 70 to 170 µm.