Despite the great interest in the safe and compact storage of hydrogen in the form of metal-hydrides, obtaining alloys capable of reversibly and rapidly storing large amounts of hydrogen at ambient conditions represents a challenge. High-entropy alloys (HEAs) have great potential for hydrogen storage (HS) applications because of their broad compositional design space. In this study, we designed and synthesized V₃₅Ti₃₅Cr₁₀Fe_20−xMn_x (x = 6, 8, 10, 12, and 14) alloys based on high entropy engineering for room temperature HS. With an increase in the Mn/Fe ratio, the abundance of the body-centered cubic (BCC) phase gradually increased until the formation of a single-phase BCC-structured solid-solution alloy. The V₃₅Ti₃₅Cr₁₀Fe₆Mn₁₄ alloy reached 3.79 wt.% of hydrogen absorption at 298 K, which is the highest capacity reported for HEAs. All alloys were fully activated in one hydrogen ab/desorption cycle and saturated with hydrogenation within 100 s. Quasi-in situ X-ray diffraction characterization of the hydrogenation of HEAs revealed a phase transition from BCC to face-centered cubic (FCC) with an intermediate pseudo-BCC structure. The cycling characteristics of the alloys evidenced that their stability gradually increased with decreasing Mn content. The microstructural analysis revealed that the capacity decay of HEAs during cycling is mainly caused by lattice deformation from repeated expansion and contraction. In addition, the HS properties of HEAs were investigated by a combination of first-principles simulation and experiments. Moreover, the thermal conductivity of the alloys was investigated. This work provides new perspectives for the design of HS alloys that can rapidly absorb large amounts of hydrogen under ambient conditions.

High density and safe storage of hydrogen are the preconditions for the large-scale application of hydrogen energy. Herein, the hydrogen storage properties of Ti_0.6Zr_0.4Cr_0.6Mn_1.4 alloys are systematically studied by introducing Y element instead of Ti element through vacuum arc melting. After the partial substitution of Y, a second phase of rare earth oxide is added in addition to the main suction hydrogen phase, C14 Laves phase. Thanks to the unique properties of rare earth elements, the partial substitution of Y can not only improve the activation properties and plateau pressure of the alloys, but also increase the effective hydrogen storage capacity of the alloys. The comprehensive properties of hydrogen storage alloys are improved by multidimensional regulation of rare earth elements. Among them, Ti_0.552Y_0.048Zr_0.4Cr_0.6Mn_1.4 has the best comprehensive performance. The alloy can absorb hydrogen without activation at room temperature and 5 MPa, with a maximum hydrogen storage capacity of 1.98 wt.%. At the same time, it reduces the stability of the hydride and the enthalpy change value, making it easier to release hydrogen. Through theoretical analysis and first-principle simulation, the results show that the substitution of Y element reduces the migration energy barrier of hydrogen and the structural stability of the system, which is conducive to hydrogen evolution. The alloy has superior durability compared to the original alloy, and the capacity retention rate was 96.79% after 100 hydrogen absorption/desorption cycles.

All-solid-state lithium batteries (ASSLBs) are promising for safety and high-energy-density large-scale energy storage. In this contribution, we propose a Li_3–4xZr_xPS₄ (LZPS) by Zr-doped β-Li₃PS₄ (LPS) as a novel solid electrolyte (SE) for ASSLBs based on experimental and simulation methods. The structure, electronic property, mechanical property, and ionic transport properties of LZPS (x = 0, 0.03, 0.06, and 0.1) are investigated with first-principles calculations. Meanwhile, LZPS is prepared by solid states reaction method. By combining experimental analysis and first-principles calculations, it is confirmed that a small amount of Zr⁴⁺ can be successfully doped into the framework of β-LPS composites without significantly compromising structural integrity. When the Zr⁴⁺ concentration is x = 0.03, the doped material Li_2.88Zr_0.03PS₄ exhibits the highest ionic conductivity (5.1 × 10⁻⁴ S·cm⁻¹) at 30 °C, and the Li-ion migration energy barrier is the lowest. The Li_2.88Zr_0.03PS₄ SE has obtained the best mechanical properties, the good ductility, and shear deformation resistance, which can better maintain the structural stability of the battery. In addition, the Li/Li symmetrical cell is assembled, which shows excellent electrochemical stability of electrolyte against lithium. The constructed all-solid-state batteries (LiCoO₂-Li₆PS₅Cl|Li_2.88Zr_0.03PS₄|Li-In) delivers an initial discharge capacity of 130.4 mAh·g⁻¹ at 0.2 C and a capacity retention of 85.1% after 100 cycles at room temperature. This study provides a promising electrolyte for the application of ASSLBs with high ionic conductivity and excellent stability against lithium.