Applicable Scenarios:

Liquid hydrogen storage tanks, liquid hydrogen tank trucks, airborne liquid hydrogen storage & supply systems, cryogenic heat exchange / adsorption buffer units

Preface

Liquid hydrogen is stored at an ultra-low temperature of -253 °C with an extremely low latent heat of vaporization. Minor heat leakage will lead to liquid hydrogen boil-off loss. Other prevalent industry pain points include uneven temperature distribution inside tanks, local overpressure, poor heat transfer for adsorption hydrogen storage, and insufficient cryogenic shock absorption.

Metallic nickel foam (open-cell 3D interconnected nickel skeleton) features outstanding cryogenic toughness, tunable thermal conductivity, high specific surface area, hydrogen embrittlement resistance, porous fluid diversion and energy absorption & cushioning properties. It can be applied to insulation interlayers of liquid hydrogen tanks, inner liner heat exchange supports, filling media for adsorption hydrogen storage, pipeline flow restriction buffers, and cryogenic catalytic impurity removal units. It effectively cuts liquid hydrogen boil-off rate, improves storage & transportation safety, and reduces equipment weight. This specification comprehensively elaborates on material properties of nickel foam, its application forms in liquid hydrogen storage and transportation, assembly processes, cryogenic operation standards, fault management and acceptance criteria.

Fundamental Cryogenic Properties of Metallic Nickel Foam (Adapted to -253 °C Liquid Hydrogen Service)

① Structural Parameters of the Material

● Structure: Fully connected open-cell mesh nickel foam; porosity adjustable from 70% to 95%; pore size ranging 0.2–3 mm; rib thickness 10–50 μm

● Material: High-purity electrolytic nickel (Ni ≥ 99.95%); low impurity content, no carbon precipitation to avoid blockage of flow channels by precipitated impurities at cryogenic temperatures

● Cryogenic mechanical performance: No cold brittleness at 20 K (-253 °C); no cracking or skeleton fracture after repeated temperature cycling

● Hydrogen resistance: Nickel-based material resists hydrogen embrittlement and hydrogen permeation; no hydrogen-induced lattice cracking after long-term immersion in liquid hydrogen

● Thermal conductivity: Continuous 3D metallic network with equivalent thermal conductivity of 8–90 W/(m·K); heat transfer capacity can be precisely adjusted by varying porosity

● Specific surface area: Up to 6000 m³/m³, suitable for cryogenic adsorption, gas-liquid separation and catalytic purification

② Core Advantages for Liquid Hydrogen Storage & Transportation

● Uniform temperature heat transfer to reduce boil-off loss

Filled between tank inner liners and adsorption hydrogen storage media to form a full-range 3D heat conduction network. It eliminates local hot spots inside tanks, quickly equalizes temperature during hydrogen charging and discharging, suppresses vaporization from local overheating, and drastically lowers the daily boil-off rate of liquid hydrogen.

● Fluid diversion + gas-liquid separation

Porous channels guide vaporized hydrogen to prevent gas blockage; tiny liquid hydrogen droplets are trapped by pore channels to reduce flash vaporization loss and raise effective hydrogen storage volume utilization.

● Energy absorption and vibration damping against cryogenic impact

The porous nickel foam skeleton dissipates energy via buckling under compression. Used as internal buffer supports for tanks and vibration-damping liners for pipelines, it mitigates shocks from transportation jolts and cryogenic thermal cycling, protecting insulation layers and welds of inner liners.

● Heat transfer carrier for adsorption hydrogen storage

Composite filling with MOF and activated carbon solid adsorbents solves the problem of concentrated heat release/absorption during adsorption and desorption, greatly boosting adsorption capacity and hydrogen charging/discharging speed.

● Carrier for cryogenic catalytic purification

Its high specific surface area supports loaded noble metal catalytic layers, which remove trace oxygen and nitrogen impurities from liquid hydrogen at cryogenic temperatures to guarantee high-purity liquid hydrogen storage and transportation.

●Lightweight composite structure

With equivalent heat exchange and load-bearing performance, its weight is only 1/5 to 1/3 of solid metal components, meeting lightweight requirements for aerospace and vehicle-mounted liquid hydrogen equipment.

Typical Application Forms of Nickel Foam in Liquid Hydrogen Storage & Transportation Systems

① Heat Exchange Filling Layer for Liquid Hydrogen Tank Inner Liners

● Layout: Gradient-porosity nickel foam filled in layers at the bottom, side walls and top of liners (high-porosity foam at the bottom for liquid hydrogen diversion, medium-porosity foam on side walls for uniform heat conduction)

● Functions: Rapid cold distribution during liquid filling and uniform heat supplementation during liquid discharge, avoiding local supercooling icing and sudden pressure spikes

● Applicable equipment: Large stationary liquid hydrogen storage tanks, vehicle-mounted liquid hydrogen tank containers, aerospace liquid hydrogen Dewars

② Insulation Support & Buffer Components in Vacuum Interlayers

Cut-to-size nickel foam spacers replace conventional solid supports to separate inner and outer tanks, absorb vibration shocks during transportation, and reduce solid heat leakage. Used together with multi-layer insulation films, they balance thermal insulation and structural protection.

③ Composite Skeleton for Solid-State Adsorption Hydrogen Storage

Low-temperature adsorbents are filled inside nickel foam pores to form an integrated core combining heat conduction skeleton and adsorption media. It addresses the drawbacks of poor heat transfer and slow hydrogen charging/discharging in adsorption hydrogen storage, suitable for small mobile auxiliary liquid hydrogen storage units.

④ Flow Restrictors & Gas-Liquid Separation Filter Elements for Liquid Hydrogen Pipelines

Thin nickel foam is fabricated into cryogenic filters installed on liquid outlet and pressure relief pipelines to trap liquid hydrogen droplets while allowing hydrogen gas to pass through, cutting liquid hydrogen loss during pressure relief. It also buffers gas flow surges and stabilizes pipeline pressure.

⑤ Carrier for Cryogenic Impurity Removal Catalysts

Surface modification generates Cu²⁺-rich nickel-based catalytic layers, which catalyze the removal of trace air impurities during liquid hydrogen vaporization at low temperatures to ensure hydrogen purity, for aerospace-grade high-purity liquid hydrogen storage and transportation systems.

Pre-Treatment Process (Mandatory for -253 °C Cryogenic Service)

Nickel foam has a high specific surface area and readily absorbs oil stains, dust and moisture. Direct deployment without pre-treatment will cause pore blockage by ice at cryogenic temperatures and impurity contamination of liquid hydrogen. The three-step pre-treatment process is as follows:

① Visual Sorting

Inspect nickel foam for broken skeletons, powder shedding, oxidation rust spots and stamping deformation; reject parts with surface oil stains or residual resin.

② Deep Ultrasonic Cleaning

Ultrasonically clean sequentially with anhydrous ethanol and high-purity deionized water for 15–30 minutes to remove processing grease and metallic dust. Chlorine-containing detergents are strictly prohibited to avoid cryogenic chloride corrosion.

③ High-Temperature Vacuum Drying & Activation

Dry at 200–280 °C under high-purity nitrogen shielding, hold under vacuum for 1–2 hours to completely remove adsorbed moisture inside pores. Cool to room temperature and seal under vacuum packaging to isolate air and moisture before assembly.

Assembly & Filling Specifications

① Dimensional Matching

Cut nickel foam with a reserved compression allowance of 0.5%–1%. After filling, slight compression ensures full contact with liner walls for continuous thermal conduction of the skeleton; suspension is not allowed. Over-compression that collapses pores and blocks fluid channels is forbidden.

② Layered Gradient Filling

Tank sections adopt nickel foam with different porosities:

● Bottom: 90%–95% porosity (liquid hydrogen diversion)

● Middle: 75%–85% porosity (uniform heat conduction)

● Top: 70%–75% porosity (vaporized gas buffering)

③ Sealing & Isolation

Seal the tank immediately after filling, evacuate and replace with high-purity nitrogen at least three times to expel air from interlayers and pores. Open-air assembly in humid environments is prohibited.

④ Composite Filling Process (Adsorption Hydrogen Storage Units)

Impregnate solid adsorbents uniformly into nickel foam pores under negative vacuum pressure, followed by low-temperature curing to avoid local voids that degrade heat transfer performance.

Material Acceptance Technical Indicators

Conclusion

With superior ultra-low temperature mechanical stability, tunable 3D thermal conductivity, porous fluid regulation and impact energy absorption capabilities, metallic nickel foam systematically addresses core bottlenecks of liquid hydrogen storage and transportation tanks including uneven heat transfer, gas-liquid separation, vibration protection and poor heat transfer of solid-state adsorption hydrogen storage.

Strict implementation of pre-filling cleaning & drying, gradual temperature change control, layered filling and regular inspection standards enables long-term stable operation on stationary liquid hydrogen storage tanks, vehicle-mounted liquid hydrogen tank trucks, airborne liquid hydrogen storage & supply equipment. It effectively reduces liquid hydrogen boil-off loss, improves overall safety and stability of storage & transportation systems, and meets the scaled development demands of cryogenic liquid hydrogen storage and transportation in the hydrogen energy industry.

References

If you would like to order custom metal foam or porous metal, please call Huayan Intelligent Technology at +8613661985902，Email: 13661985902@163.com