The development of safe, efficient, and economical technologies of hydrogen storage is essential for advancing hydrogen energy utilization. Physisorption hydrogen storage materials, renowned for their high theoretical capacity, rapid adsorption/desorption kinetics, and superior reversibility, hold significant promise. However, despite impressive performance at cryogenic temperatures, their hydrogen storage capacity at or near room temperature remains a great challenge to satisfy practical demands due to their weak interaction with hydrogen molecules. In this review, recent important advancements in porous hydrogen storage materials are summarized, including porous carbon, MOFs, COFs, porous polymers, as well as porous BN and 2D porous materials. Furthermore, we elaborate on key terminologies related to these materials, highlighting the crucial balance between gravimetric and volumetric hydrogen storage capacity and the importance of enhancing the usable capacity for vehicular applications. To increase the hydrogen adsorption isosteric heat, several primary hydrogen storage mechanisms are summarized, followed by a detailed discussion on modification strategies to realize those mechanisms and the main challenges hindering their implementation. Finally, insights and potential research directions are provided in material design, mechanism exploration, engineering, and commercialization of physisorption hydrogen storage materials, aiming to inspire the development of next-generation hydrogen storage solutions.
Carbide ceramics (e.g. ZrC, B4C, SiC) have a wide range of applications in aerospace, machining, electronics, energy and chemical industry, catalysis, energy storage and other fields due to their exceptional hardness, high melting point, excellent high-temperature thermal stability, high chemical durability, and good electrical conductivity. With the rapid development of modern technology, carbide ceramics prepared by traditional methods have become increasingly difficult to meet the rising structural functionalization requirements. The advent of additive manufacturing technologies, which effectively reduce production costs and increase freedom of design, has made it possible to prepare carbide ceramic parts with complex geometries at low cost, high efficiency, and in large sizes. The performance of additive manufacturing components is closely related to the material composition, raw material preparation, structure design, additive manufacturing process, forming process, and post-processing method, etc. This paper summarizes the method for determining the intrinsic physical properties of carbide ceramics, systematically evaluates the main technologies currently used in the additive manufacturing of carbide ceramics (including laser powder bed fusion, VAT photopolymerization, direct ink writing and binder jetting), comprehensively reviews the current research progress on additive manufacturing of carbides, emphatically analyzes the formation mechanisms of various defects (e.g. porosity, cracks, delamination) in different processes and their intrinsic correlations with mechanical properties, carries out an in-depth analysis on the state-of-the-art technologies and difficulties in carbide ceramic additive manufacturing, and proposes a perspective on the development of the future carbide ceramic additive manufacturing and applications.
Inkjet printing (IJP) has emerged as a promising additive manufacturing (AM) route for oxide ceramics owing to its maskless digital deposition, high material utilization, non-contact patterning, and compatibility with multimaterial integration. However, achieving reproducible and dimensionally controlled printing of oxide ceramics remains challenging because the final printed geometry is governed by coupled processes from ink formulation and jetting to deposition, drying, and post-processing. Although substantial progress has been made in oxide ceramic ink formulation and functional applications, the relationships among ink properties, droplet dynamics, deposition behavior, pattern formation, and final ceramic performance remain insufficiently integrated. In this context, this review provides a critical overview of recent advances in oxide ceramic IJP, with particular emphasis on the relationships between material and process variables and measurable printing outcomes across the process chain. First, the fundamental principles of drop-on-demand (DOD) IJP and key printability criteria are introduced. Then, oxide ceramic ink design strategies are summarized, with emphasis on rheological regulation and dispersion stability. Next, droplet formation, satellite suppression, waveform optimization, deposition behavior, and drying-induced nonuniformity are discussed. Strategies for coffee ring suppression through solvent engineering, additive design, and substrate modification are further reviewed. Representative applications in structural components, electronics, energy devices, and sensors are summarized. Finally, current challenges and future prospects are discussed, particularly the printability of particle-loaded inks, long-term process reliability, dimensional control, scale-up, and closed-loop process optimization for reproducible oxide ceramic manufacturing.
High-entropy alloys (HEAs), characterized by their multi-principal element compositions, offer unprecedented opportunities to overcome the strength-ductility trade-off in structural materials. Despite their promising mechanical properties, the widespread application of HEAs remains limited by the difficulty of achieving simultaneous enhancement of strength and ductility. In response, various strengthening strategies have been adapted to enhance their mechanical performance. Due to the inherent compositional and microstructural complexity of HEAs, their strengthening mechanisms often differ from those of conventional alloys, making them a noteworthy subject for review. This review provides a comprehensive and critical assessment of recent progress in strengthening methods for HEAs, with particular emphasis on solid solution strengthening, dislocation strengthening, second-phase strengthening, grain-boundary and twin-boundary strengthening, twinning/phase transformation-induced plasticity, and hetero-deformation-induced strengthening. The interdependence between alloy composition, processing routes, microstructural evolution, and mechanical performance is systematically discussed. Special attention is given to the challenges in applying classical strengthening theories to HEAs and to the role of compositional design and thermomechanical processing in enabling tailored microstructures. Overall, this review not only clarifies the distinctive strengthening physics of HEAs and guides the design of high-performance HEAs via composition–processing–microstructure integration, but also offers transferable insights for extending and refining classical strengthening frameworks in conventional alloys.
