Monolayer 2D Material Membranes for Proton Conduction
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Solution Overview
Problem
Existing membranes, particularly those made from graphene, are impermeable to thermal protons and ions, limiting their application in hydrogen-based technologies and fuel cells due to high energy barriers and inefficient proton conduction.
Innovation Solution
Development of monolayer or few-layer membranes from graphene, hexagonal boron nitride (hBN), molybdenum disulfide (MoS2), and tungsten disulfide (WS2) with an ionomer coating, allowing for proton and deuteron conductivity through the material's crystal structure rather than defects, enabling thinner, more efficient membranes for fuel cells and hydrogen separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If monolayer graphene or 2D material membranes are used, then mechanical strength and barrier properties are improved, but proton conductivity deteriorates due to high energy barriers
Solution Approach 1:
The patent introduces an intermediary substance (ionomer or catalytic metal) between the proton source and the 2D material membrane. The ionomer coating on the membrane surface acts as a mediator that facilitates proton transfer by providing a lower energy pathway, while the catalytic metal particles (Pt, Pd, Au) serve as intermediaries that catalyze proton penetration through the membrane. This resolves the contradiction by maintaining the mechanical strength of the 2D material while enabling proton conductivity through the intermediary's facilitation.
Solution Approach 2:
The patent changes the energy parameter of the system by introducing catalytic metals that lower the activation energy barrier for proton penetration. The catalytic particles modify the energy landscape, creating favorable energy states that enable thermal protons to penetrate the otherwise impermeable 2D material. This parameter change (reducing energy barrier from eV scale to accessible levels) resolves the contradiction between barrier properties and proton conductivity.
2Reliability
If ionomer coating is applied to enhance proton conductivity, then proton conduction is improved, but device complexity increases
Solution Approach 1:
The patent employs an ultra-thin ionomer coating (nanometer to sub-nanometer scale) on the 2D material membrane surface. This thin film approach provides the necessary proton conduction functionality while minimizing the addition of structural complexity. The ionomer layer is sufficiently thin that it does not significantly add to the overall device complexity, yet it effectively enhances proton conduction by providing a favorable pathway for proton transport.
3Reliability
If catalytic metal particles are deposited to facilitate proton penetration, then proton penetration is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs a low coverage density of catalytic metal particles on the 2D material surface rather than requiring complete or uniform coverage. This partial action approach means that only a small number of strategically positioned catalytic particles are needed to provide sufficient proton conduction pathways. This significantly reduces the manufacturing precision requirements, as the system does not demand precise control over particle placement, size, or uniformity - random deposition at low coverage is sufficient to achieve the desired effect.
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 membranes achieve efficient proton and deuteron conduction at ambient temperatures, reducing electrical resistance and enabling selective barrier properties, improving fuel cell efficiency and hydrogen separation while preventing the diffusion of other species like water and methanol.
Implementation Method 1
monolayers of graphene and hexagonal boron nitride (hBN) which are surprisingly permeable to thermal protons, i.e. hydrogen ions under ambient conditions
Implementation Method 2
the protons move through the body of the material itself i.e. through its crystal structure
Implementation Method 3
an ionomer coating provided on at least one side of the 2D material... enabling selective barrier properties, improving fuel cell efficiency and hydrogen separation while preventing the diffusion of other species like water and methanol
Data Source
AI summary
The present invention relates to a graphene-based or other 2-D material membrane which allows the passage of protons and deuterons and to a method of facilitating proton or deuteron permeation through such a membrane. Monocrystalline membranes made from mono- and few-layers of graphene, hBN, molybdenum disulfide (MoS2), and tungsten disulfide (WS2) etc. are disclosed. In effect, the protons or deuterons are charge carriers that pass through the graphene or other 2-D material membrane. This process can be contrasted with the passage of gaseous hydrogen. Hydrogen is an uncharged gaseous species which is diatomic. In other words, the gas is in molecular form when considering the normal barrier properties whereas in the case of the present invention, the species which is being transported through the membrane is a charged ion comprising a single atom. Membranes of the invention find use in a number of applications such as fuel cells.