Hydrogen Storage Materials Using Liquid Electrolytes
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Solution Overview
Problem
Current hydrogen storage methods for fuel cell applications face challenges such as high energy requirements for compression, low storage densities, impractical release temperatures, and slow hydrogen exchange rates, limiting their efficiency and practicality for commercial use.
Innovation Solution
A hydrogen-storage material formulation comprising a solid hydrogen-storage material bonded ionically, covalently, or interstitially with a metal or metalloid, combined with a liquid electrolyte that is ionically conductive, enhancing hydrogen evolution rates and allowing for reversible dehydrogenation-hydrogenation cycles at practical temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrogen is stored as compressed gas, then storage density is improved, but high pressure requirements increase energy consumption and safety challenges
Solution Approach 1:
The patent changes the storage mechanism from physical compression to chemical bonding, fundamentally altering the parameters of hydrogen storage. By forming metal hydrides where hydrogen is chemically bonded to metal atoms, the system achieves high storage density without requiring high compression pressures, thus resolving the contradiction between storage density and compression energy.
Solution Approach 2:
The patent replaces the mechanical compression system with a chemical bonding system. Instead of using mechanical pressure to increase storage density, the invention uses chemical reactions to form stable metal hydride compounds that store hydrogen at lower pressures, eliminating the need for high-pressure compression equipment and reducing energy consumption.
2Quantity of substance
If light metal hydrides are used for hydrogen storage, then storage density is improved, but release temperature becomes impractically high
Solution Approach 1:
The patent uses composite materials combining light metals (such as lithium, sodium, or magnesium) with hydrogen to form metal hydrides. These composite structures achieve high storage density while the specific composition allows for controlled release temperatures. The composite nature enables tuning of thermodynamic properties to balance storage density and release temperature requirements.
Solution Approach 2:
The patent applies local quality by selecting specific metal-hydrogen compositions that have favorable local thermodynamic properties. By choosing particular metal hydride formulations with appropriate bonding characteristics, the system achieves both high storage density and practical release temperatures, rather than using uniform storage approaches.
3Temperature
If transition metal hydrides are used, then release temperature is reduced, but storage density becomes too low
Solution Approach 1:
The patent inverts the conventional approach by using light metals instead of transition metals for hydrogen storage. This inversion achieves the opposite effect: while transition metals provide easy release, light metals provide high storage density. The patent compensates for the higher release temperature by using composite formulations and controlled release mechanisms.
Solution Approach 2:
The patent employs composite materials that combine light metals with hydrogen in specific ratios to optimize both storage density and release characteristics. These composite metal hydrides achieve storage densities exceeding 4 wt% while maintaining release temperatures that are practical for applications, resolving the contradiction between these two parameters.
4Quantity of substance
If hydride mixtures are used to tune thermodynamics, then storage density is improved, but hydrogen exchange rate becomes slow
Solution Approach 1:
The patent applies preliminary action by pre-forming the metal hydride compounds with optimized compositions before use. The hydride mixtures are prepared in advance with specific phase distributions and microstructures that facilitate rapid hydrogen exchange. This preliminary preparation ensures both high storage density and fast kinetics without requiring complex in-situ adjustments.
Solution Approach 2:
The patent utilizes porous materials and nanoscale structures to increase the surface area and reduce diffusion path lengths for hydrogen exchange. By incorporating porous supports or creating nanoscale hydride particles, the system maintains high storage density while dramatically improving hydrogen exchange rates through enhanced mass transport pathways.
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 formulation achieves higher hydrogen density storage and efficient hydrogen release at lower pressures, eliminating the need for cryogenic cooling and improving the kinetics of hydrogen exchange, making high-hydrogen-density storage materials practical for portable power and fuel cell applications.
Implementation Method 1
a liquid electrolyte that is ionically conductive for at least one ion derived from the hydrogen-storage material
Implementation Method 2
a solid hydrogen-storage material containing at least one metal and hydrogen that is bonded ionically, covalently, and/or interstitially
Data Source
AI summary
In some variations, a hydrogen-storage material formulation comprises: a solid hydrogen-storage material containing at least one metal and hydrogen that is bonded with the metal; and a liquid electrolyte that is ionically conductive for at least one ion derived from the hydrogen-storage material. The liquid electrolyte may be from 5 wt % to about 20 wt % of the hydrogen-storage material formulation, for example. Many materials are possible for both the hydrogen-storage material as well as the liquid electrolyte. The hydrogen-storage material has a higher hydrogen evolution rate in the presence of the liquid electrolyte compared to a hydrogen-storage material without the liquid electrolyte. This is experimentally demonstrated with a destabilized metal hydride, MgH2/Si system, incorporating a LiI—KI—CsI ternary eutectic salt as the liquid electrolyte. Inclusion of the liquid electrolyte gives a ten-fold increase in H2 evolution rate at 250° C., reaching 3.5 wt % hydrogen released in only 7 hours.