Key Takeaways & Executive Findings
- •• V–Ti-based solid solution alloys exhibit reversible hydrogen storage capacity exceeding 2 wt% at ambient temperatures, making them promising for solid-state hydrogen storage. • Hydrogen storage performance is critically influenced by elementary composition, phase structure, and homogeneity of the alloy. • Micro-strain accumulation during cycling is identified as a primary cause of capacity degradation in V–Ti-based alloys. • Future development should focus on low-cost, high-performance alloys with enhanced cyclic durability and activation performance for practical MH tank applications.
Abstract
This review details the advancement in the development of V–Ti-based hydrogen storage materials for using in metal hydride (MH) tanks to supply hydrogen to fuel cells at relatively ambient temperatures and pressures. V–Ti-based solid solution alloys are excellent hydrogen storage materials among many metal hydrides due to their high reversible hydrogen storage capacity which is over 2 wt% at ambient temperature. The preparation methods, structure characteristics, improvement methods of hydrogen storage performance, and attenuation mechanism are systematically summarized and discussed. The relationships between hydrogen storage properties and alloy compositions as well as phase structures are discussed emphatically. For large-scale applications on MH tanks, it is necessary to develop low-cost and high-performance V–Ti-based solid solution alloys with high reversible hydrogen storage capacity, good cyclic durability, and excellent activation performance.
1. Introduction
Solid-state hydrogen storage technology has received widespread attention because of the application of hydrogen energy in full swing and the requirement of high volumetric and gravimetric density candidates [1–3]. For on-board hydrogen storage, the vehicle-mounted hydrogen storage device is a reservoir that supplies hydrogen to fuel cells, which also requires a suitable hydrogen absorption/desorption rate at ambient temperature [4], as shown in Fig. 1. Consequently, acceptable economic cost, long cycle life, and safety for complex working conditions are more necessary for on-board hydrogen storage devices. In view of these, solid-state hydrogen storage technology provides an option to store hydrogen under non-extreme conditions (e.g., avoid 70 MPa or −253 °C) [5].
Traditional hydrogen storage alloys, such as AB5-type, AB-type, and AB2-type alloys, typically have hydrogen capacities of less than 2.0 wt% [6, 7]. Despite the magnesium-based alloys having a higher hydrogen capacity (7.6 wt%), their high dehydrogenation temperature limits their application in on-board hydrogen storage devices [8–12]. Of course, by adding catalysts or applying nanoscale techniques, the dehydrogenation temperature can be effectively reduced while maintaining a hydrogen storage capacity above 6 wt% [13–15]. However, the actual dehydrogenation temperature is still difficult to match with the fuel cell module [16–18]. Metal borohydrides face a similar dilemma, and there is also the cost to consider [19]. Although the cost can be reduced by regenerating metal borohydrides from hydrolyzed products, further research is needed in terms of high dehydrogenation temperature, slow dehydrogenation kinetics and poor reversibility [20–22]. Reassuringly, V–Ti-based solid solution alloys exhibit a reversible hydrogen storage capacity of over 2.0 wt% at temperatures below 100 °C and are expected to be used on solid-state hydrogen storage devices [23, 24].
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Shaoyang Shen, Yongan Li, Liuzhang Ouyang, Lan Zhang, Min Zhu, Zongwen Liu (2025). V–Ti-Based Solid Solution Alloys for Solid-State Hydrogen Storage. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01672-w
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Frequently Asked Questions
What are V–Ti-based solid solution alloys?
V–Ti-based solid solution alloys are hydrogen storage materials composed primarily of vanadium and titanium, often with additional metallic elements, that can reversibly absorb and desorb hydrogen at ambient temperatures, with capacities exceeding 2 wt%.
Why are V–Ti-based alloys promising for solid-state hydrogen storage?
They offer high reversible hydrogen storage capacity (over 2 wt%) at relatively low temperatures (below 100 °C), suitable hydrogen equilibrium pressure, and good anti-pulverization performance, making them suitable for metal hydride tanks in fuel cell applications.
What factors affect the hydrogen storage performance of V–Ti-based alloys?
The performance is influenced by elementary composition, phase structure, and homogeneity of the alloy. Micro-strain accumulation during cycling is also responsible for capacity degradation.
What are the challenges for large-scale application of V–Ti-based alloys?
Challenges include low effective hydrogen storage capacity, uneven plateau area, limited cyclic durability, and the need for low-cost and high-performance alloys with good activation performance.
How can the performance of V–Ti-based alloys be improved?
Improvement methods include adding multiple metallic elements to tailor composition and phase structure, optimizing preparation methods, and addressing micro-strain accumulation to enhance cyclic stability.
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