Related Experiment Video
Updated: Jun 19, 2026
10:59
Mass Cytometry: Protocol for Daily Tuning and Running Cell Samples on a CyTOF Mass Cytometer
Published on: November 2, 2012
22.7K
Tuning TiFe1- Ni Hydride Thermodynamics through Compositional Tailoring
Evans Pericoli1, Viola Ferretti1, Dario Verna1
1Department of Physics and Astronomy A. Righi, University of Bologna, Bologna 40127, Italy.
ACS Applied Energy Materials
|February 28, 2025
Summary
Nickel substitution in Titanium Iron (TiFe) alloys effectively lowers hydrogen plateau pressure for better solid-state storage. This modification enhances hydride formation thermodynamics, making TiFe alloys more suitable for near-ambient conditions.
Area of Science:
- Materials Science
- Physical Chemistry
- Solid-State Physics
Background:
- Titanium Iron (TiFe) intermetallic alloys are promising for reversible solid-state hydrogen storage.
- Reducing the plateau pressure of TiFe is critical for applications under near-ambient conditions (e.g., <150 °C, <50 bar).
- Structural modifications can tune the thermodynamic properties of metal hydrides.
Purpose of the Study:
- To investigate the effect of Nickel (Ni) substitution for Iron (Fe) in TiFe alloys on hydride formation and decomposition thermodynamics.
- To determine if Ni incorporation can lower the plateau pressure of TiFe.
- To analyze the thermodynamic stabilization of hydrides and the enthalpy-entropy compensation effect.
Main Methods:
- Synthesis of TiFe1-xNix alloys (x ≤ 0.30) via arc melting.
- Characterization of structural and morphological properties using powder X-ray diffraction (PXRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS).
- Thermodynamic property investigation using volumetric measurements (Sieverts' apparatus) and high-pressure differential scanning calorimetry (HP-DSC).
Main Results:
- Ni incorporation effectively reduces the plateau pressure of TiFe alloys.
- The enthalpy of hydride formation becomes more negative with increasing Ni content, stabilizing the hydride.
- The entropy of hydride formation increases with Ni content, showing a linear correlation between enthalpy and entropy values.
- Analysis suggests a genuine enthalpy-entropy compensation effect in the Ni-substituted TiFe system.
Conclusions:
- Nickel substitution is an effective strategy to tune the thermodynamic properties of TiFe alloys for hydrogen storage.
- The observed enthalpy-entropy compensation effect warrants further investigation into its origin.
- Optimized TiFe-Ni alloys show potential for improved reversible solid-state hydrogen storage applications.
Related Concept Videos
02:59Enthalpy
Chemists ordinarily use a property known as enthalpy (H) to describe the thermodynamics of chemical and physical processes. Enthalpy is defined as the sum of a system’s internal energy (E) and the mathematical product of its pressure (P) and volume (V):
01:23Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
01:16Thermal Sigmatropic Reactions: Overview
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
01:34Radical Halogenation: Thermodynamics
The thermodynamic favorability of a reaction is determined by the change in Gibbs free energy (ΔG). ΔG has two components- enthalpy (ΔH) and entropy (ΔS). The entropy component is negligible for alkane halogenation because the number of reactants and product molecules are equal. In this case, the ΔG is governed only by the enthalpy component. The most crucial factor that determines ΔH is the strength of the bonds. ΔH can be determined by comparing the energy between bonds broken and bonds...
01:06Thermodynamic Systems
A thermodynamic system is a set of objects whose thermodynamic properties are of interest. The system is considered to be embedded in its surroundings or the environment. The system and its environment can exchange heat and do work on each other through a boundary that separates them. However, the immediate surroundings of the system interact with it directly and therefore have a much stronger influence on its behavior and properties.
Consider an example of tea boiling in a kettle. The tea and...
Consider an example of tea boiling in a kettle. The tea and...
01:25Thermodynamic Processes
A thermodynamic process is a path through a sequence of states that takes a system from an initial state to a final state. In a cyclic process, the system returns to its initial state, so the changes in state properties and state functions (ΔT, Δp, ΔV, ΔU, ΔH) over one complete cycle are zero. However, heat and work transfers can still occur during the cycle, and the net heat and net work over the cycle need not be zero.A reversible process occurs when the system is infinitesimally close to...