The development of nanoporous hydrogen storages

Сентябрь 9, 2022

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The development of nanoporous hydrogen storages

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2. Conventional and nonconventional hydrogen storages. Storage in high-pressure tanks – up to 700 atmospheres. Disadvantages –
3. d=3-5 nm, D=5-7 nm d=5-8 nm, D=8-10 nm Porosity – 20% The initial stage of film
4. Nanocrystalline porous complex hydrides (V, Ti)NxHy
5. Structural changes in VNx films by absorption and desorption of hydrogen. Scanning and transmission microscopy. Initial
6. Hydrogen absorption by TiNx, (V, 0,1Ti)Nx films TiNx Porosity – 32% Porosity – 9% (V, 0,1Ti)Nx
7. The diagram of hydrogen absorption by nanoporous structures Adsorption & diffusion Nano pores filling Hydrogen dissociation
8. Hydrogen desorption by TiN, VN and VN+Ni films The hydrogen desorption starts at 50°С. The maximum
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Conventional and nonconventional hydrogen storages.
Storage in high-pressure tanks – up to

700 atmospheres.
Disadvantages – spontaneous leak of hydrogen and high risk of depressurization.
Storage in liquid state– (-252°С).
Disadvantages – thigh cost of equipment for hydrogen storage and cooling, evaporation and high risk of depressurization.

Hydrogen storage in solid state.
Requirements.
Gravimetric capacitance- > 6 weight % H2, Hydrogen pressure at its saturation - < 3 МPа,
Hydrogenation time - < 5 minutes, Temperature of hydrogen desorption - < 85°С

Porous
(physical adsorption)
1. Carbon nanostructures
Nanotubes (single-layer, multilayer),
nanofibers, fullerene, graphene,
activated carbon.
2. Metal - organic structures
MOF-5,177 (Zn4O-[O2C-C6H4-CO2]2),
MIL-53,101(Cr,Al,O [O2C-C6H4-CO2]2),
IMOF-1,3,12 (Zn4O-CxHy(CO2)2)

Compact
(chemical adsorption)
Mg - based hydrides
MgH2 – (Ti, V, Ni, Cu, Fe, Mn),
MgH2 – (V2O5, Nb2O5, Fe2O3, Al2O3, TiO2)
Complex hydrides
NaAlH6, LiAlH4, KAlH4
3. LiN - based hydrides
LiNH2, Li2NH, Li2MgN2H2, Li3BN2H8
4. Intermetallic compounds
LaNi5, FeTi, TiVCr, TiZrNi, TiCrMn

So far none of the solid-state hydrogen accumulators satisfy
the necessary requirements.

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d=3-5 nm,
D=5-7 nm
d=5-8 nm,
D=8-10 nm
Porosity – 20%
The initial stage

of film deposition.
The thickness – 10 nm

The thickness – 1 µm

Porosity – 32%

Porosity – 9%

Our idea To create such a material, which would be able to accumulate hydrogen both in its atomic and molecular states. Complex hydrides (V, Ti, Mg)Ny

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Nanocrystalline porous complex hydrides (V, Ti)NxHy

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Structural changes in VNx films by absorption and desorption of hydrogen.

Scanning and transmission microscopy.

Initial state

H2, 0,3 MPa, 1 hour, 20oC

Annealing 250oC

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Hydrogen absorption by TiNx, (V, 0,1Ti)Nx films
TiNx
Porosity – 32%
Porosity

– 9%

(V, 0,1Ti)Nx

Gravimetric capacity of nanoporous structures is determined not only by porosity, but also
by average pore size.
Relatively large pores (>8-10 nm) do not retain
hydrogen at room temperature and
atmospheric pressure.
The main part of hydrogen is accumulated
within nano grains.

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The diagram of hydrogen absorption by nanoporous structures
Adsorption & diffusion
Nano

pores filling

Hydrogen dissociation

Vacancy traps filling

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Hydrogen desorption by TiN, VN and VN+Ni films
The hydrogen desorption starts

at 50°С.
The maximum speed of hydrogen release is observed at 250°С.
2. The application of protective nickel layer of 10 nm
thick lowers the temperature of maximum
hydrogen release by 50°С and increases its total
absorbed amount by 10%.