CO2 Electrolysis Diaphragm With Graded Pores for Gas Crossover Control
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Solution Overview
Problem
Existing carbon dioxide electrolytic devices face challenges in maintaining high efficiency and preventing side reactions due to improper gas and electrolyte management, leading to reduced performance over time.
Innovation Solution
The device employs a diaphragm with two porous surfaces of different average pore sizes, one larger on the anode side to form a liquid film for gas barrier and one smaller on the cathode side to prevent electrolyte migration, combined with specific catalyst materials and structures to enhance reaction efficiency and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform porous film is used in the diaphragm, then the structure is simple and easy to manufacture, but gas crossover occurs and electrolysis efficiency decreases
Solution Approach 1:
The diaphragm is designed with a porous film having different pore sizes at different locations: a first porous surface with larger average pore size facing the anode and a second porous surface with smaller average pore size facing the cathode. This local differentiation allows the larger pores to facilitate electrolyte supply while the smaller pores prevent gas crossover, thereby maintaining high electrolysis efficiency without compromising manufacturability
2Quantity of substance
If the pore size is increased to facilitate electrolyte flow, then electrolyte supply is improved, but gas crossover increases and efficiency is reduced
Solution Approach 1:
The porous film is designed with larger average pore size at the anode-facing surface to facilitate electrolyte supply and ion transport, while the cathode-facing surface has smaller average pore size to prevent gas crossover. This local differentiation resolves the contradiction by allowing sufficient electrolyte flow where needed while blocking gas migration where harmful
Solution Approach 2:
Instead of using a single uniform pore size throughout the film thickness, the invention introduces dimensional variation in pore size along the thickness direction of the porous film. The pore size transitions from larger at the anode side to smaller at the cathode side, creating a gradient structure that simultaneously satisfies electrolyte supply requirements and gas barrier requirements
3Reliability
If the pore size is decreased to prevent gas crossover, then gas barrier property is improved, but electrolyte migration to cathode increases causing side reactions
Solution Approach 1:
The porous film is designed with larger average pore size at the anode-facing surface to facilitate electrolyte supply and ion transport, while the cathode-facing surface has smaller average pore size to prevent gas crossover. This local differentiation resolves the contradiction by allowing sufficient electrolyte flow where needed while blocking gas migration where harmful
4Device complexity
If a single porous surface structure is used, then the device complexity is low, but both gas barrier and electrolyte management cannot be optimized simultaneously
Solution Approach 1:
The porous film is designed with larger average pore size at the anode-facing surface to facilitate electrolyte supply and ion transport, while the cathode-facing surface has smaller average pore size to prevent gas crossover. This local differentiation resolves the contradiction by allowing sufficient electrolyte flow where needed while blocking gas migration where harmful
Solution Approach 2:
Instead of using a single uniform pore size throughout the film thickness, the invention introduces dimensional variation in pore size along the thickness direction of the porous film. The pore size transitions from larger at the anode side to smaller at the cathode side, creating a gradient structure that simultaneously satisfies electrolyte supply requirements and gas barrier requirements
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 maintains high electrolysis efficiency and prevents side reactions, ensuring stable performance over long durations by effectively managing gas and electrolyte flow, thereby optimizing carbon dioxide reduction.
Implementation Method 1
a first porous surface provided on an anode side and having a first average pore size, and a second porous surface provided on a cathode side and having a second average pore size. The first average pore size being larger than the second average pore size
Implementation Method 2
an anode configured to oxidize water or a hydroxide ion and thus generate oxygen
Implementation Method 3
a cathode configured to reduce carbon dioxide and thus generate a carbon compound
Implementation Method 4
The first average pore size being larger than the second average pore size... to prevent electrolyte migration
Data Source
AI summary
A carbon dioxide electrolytic device includes an anode configured to oxidize water or a hydroxide ion and thus generate oxygen; an anode solution flow path configured to supply an anode solution to the anode; a cathode configured to reduce carbon dioxide and thus generate a carbon compound; a gas flow path configured to supply a gas to the cathode, the gas containing carbon dioxide; and a diaphragm provided between the anode and the cathode and including a porous film. The porous film includes a first porous surface provided on an anode side and having a first average pore size, and a second porous surface provided on a cathode side and having a second average pore size. The first average pore size is larger than the second average pore size.