NOVELTY - The hydrogen tank (1) comprises a material such as a metal hydride capable of absorbing hydrogen via natural chemical bonds (4), and a compressible material (3) for covering a part of internal walls of the tank. The walls of reservoir are made of polymer. The compressible material includes elastomers and hollow microspheres (10-90%) made of polymers or glass, and is present in the form of cavities inside the tank. The hollow microspheres have a diameter of 100-1000 mu m.    USE - The hydrogen tank is useful for supplying hydrogen to a fuel cell, and for nomadic and mobile applications.    ADVANTAGE - The hydrogen tank can store a large amount of hydrogen in good conditions in terms of security (low pressure), energy efficiency (no compression and a temperature close to ambient temperature) and reliability, and avoids the generation of mechanical stress during the phases of absorption and desorption of hydrogen and associated cycles without diminishing the kinetic performance of intermetallic compounds or assigning an ergonomics of device.    DETAILED DESCRIPTION - The hydrogen tank (1) comprises a material such as a metal hydride capable of absorbing hydrogen via natural chemical bonds (4), and a compressible material (3) for covering a part of internal walls of the tank. The walls of reservoir are made of polymer. The compressible material includes elastomers and hollow microspheres (10-90%) made of polymers or glass, and is present in the form of cavities inside the tank. The hollow microspheres have a diameter of 100-1000 mu m. The metal hydride is expressed as ABn, where A represents a metallic element with high affinity for hydrogen and comprising an alkaline metal, an alkaline earth metal, a primary transition metal, a rare earth metal or an actinide, B denotes an element of low affinity for hydrogen and consisting of a middle or final transition metal, or an element p.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a hydrogen tank.    Tank (1)    Auto-sealing pump (2)    Compressible material (3)    Natural chemical bonds. (4)