Hydrogen Adsorbents in the Vacuum Layer of Liquid Hydrogen Containers: Materials and Applications

Hydrogen serves as a key clean-energy carrier, with the main hurdles lying in safe, efficient transport and storage (gas or liquid) and in end-use energy conversion. Liquid hydrogen (LH), as a high-density method of storage and transportation, presents cryogenic insulation as its key technical issues. In LH storage tanks, the performance of high vacuum multilayer insulation (HVMLI) will decline due to hydrogen release and leakage from the microscopic pores of steel, which significantly destroy the vacuum layer. The accumulation of residual gases will accelerate thermal failure, shorten the service life of storage tanks and increase safety risks. Adsorption is the most effective strategy for removing residual gases. This review aims to elucidate materials, methods, and design approaches related to hydrogen storage. First, it summarizes adsorbents used in liquid hydrogen storage tanks, including cryogenic adsorbents, metal oxides, zeolite molecular sieves, and non-volatile compounds. Second, it explores experimental testing methods and applications of hydrogen adsorbents in storage tanks, analyzing key challenges faced in practical applications and corresponding countermeasures. Finally, it proposes research prospects for exploring novel adsorbents and developing integrated systems.