Amine-Nitrile Redox Cell for Ambient Hydrogen Storage
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Solution Overview
Problem
Current hydrogen storage methods, such as compressed gas and cryogenic liquid, are inefficient and costly, failing to meet the U.S. Department of Energy's target of 5.5 wt. % hydrogen storage below 85° C. and 12 bar by 2025, and existing chemical conversion methods face thermodynamic challenges and high costs.
Innovation Solution
An electrochemical cell system using amine/nitrile redox couples for reversible hydrogen storage and release, operating at ambient conditions, where hydrogen is stored by hydrogenating nitriles at the anode and released by dehydrogenating amines, with catalysts like platinum and ion exchange membranes facilitating the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If compressed gas or cryogenic liquid methods are used for hydrogen storage, then hydrogen can be stored, but the energy storage density is insufficient and extreme storage conditions are required leading to increased cost and risks
Solution Approach 1:
The patent changes the storage mechanism from physical containment (compressed gas/cryogenic liquid) to chemical bonding (metal hydrides). This parameter change allows hydrogen to be stored at ambient temperature and pressure conditions while achieving high storage density through chemical conversion, resolving the contradiction between storage density and extreme temperature requirements
Solution Approach 2:
The patent replaces the mechanical storage system (high-pressure tanks, cryogenic containers) with a chemical storage system (metal hydrides). This substitution eliminates the need for extreme mechanical conditions while achieving superior storage density, directly addressing the contradiction between storage density and temperature/pressure requirements
2Ease of operation
If physisorption methods using materials like carbon nanotubes, zeolites, MOFs, or COFs are used, then hydrogen can be adsorbed to the surface, but the storage capacity is relatively low (less than 2 wt. %)
Solution Approach 1:
The patent replaces the physical adsorption mechanism (physisorption) with chemical conversion mechanisms (hydrogenation/dehydrogenation reactions). This substitution enables much higher storage capacities (exceeding 2 wt. %) while maintaining ease of operation under ambient conditions, resolving the contradiction between storage capacity and operational simplicity
3Quantity of substance
If traditional thermal strategies of LOHC are used, then hydrogen can be stored in liquid organic hydrogen carriers, but elevated temperature and pressure are required
Solution Approach 1:
The patent replaces thermal energy input with electrical energy input for the hydrogenation process. By using electrochemical cells with metal hydrides, the system achieves hydrogen storage without the elevated temperature and pressure requirements of traditional thermal LOHC methods, significantly reducing energy consumption while maintaining high storage capacity
4Productivity
If dehydrogenation reactions are used to release hydrogen from stored materials, then hydrogen can be released, but the reactions require higher applied cell potential that cannot avoid oxygen evolution reaction
Solution Approach 1:
The patent applies local quality by using different catalysts at different electrodes. The anode uses catalysts optimized for hydrogen evolution that suppress oxygen evolution, while the cathode uses catalysts for efficient dehydrogenation. This localized optimization allows high productivity hydrogen release while minimizing harmful oxygen evolution reactions
Solution Approach 2:
The patent introduces metal hydrides as intermediaries in the hydrogen release process. Instead of direct water electrolysis that produces oxygen, the system uses metal hydride dehydrogenation as an intermediate step that releases hydrogen without oxygen evolution, eliminating the harmful side reaction while maintaining high release rates
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 system achieves high-density hydrogen storage exceeding the DOE target with 5.5 wt. % hydrogen at ambient conditions, reducing costs and energy consumption, and allows for efficient energy generation from stored hydrogen.
Implementation Method 1
hydrogen is oxidized via a hydrogen oxidation reaction at the anode
Implementation Method 2
nitrile is hydrogenated to thereby store the hydrogen in a hydrogenation product amine
Implementation Method 3
the amine is converted to a generated nitrile at the anode and hydrogen is released via a hydrogen evolution reaction at the cathode
Implementation Method 4
hydrogen is released via a hydrogen evolution reaction at the cathode
Implementation Method 5
a microporous separator
Data Source
AI summary
A method and system for releasably storing hydrogen and generating electricity including an electrochemical cell including a cathode, an anode, an electrolyte, a microporous separator, an electrical connection between the cathode and the anode, an amine source, a nitrile source, a hydrogen source, and an oxygen source, wherein the electrochemical cell is configured to be operated in a hydrogen storage mode, a hydrogen release mode, and electrical generation mode. The amine/nitrile redox couple provides for full cycle electrochemical conversion of hydrogen under mild conditions.