NOVELTY - The hydrogen storage tank comprises a hydrogen inlet (21) and outlet (22) contacting with a solid body for exothermic absorption and endothermic desorption of hydrogen. The solid body is formed of a compact material comprising light metal hydride and a heat conductive matrix, and related with a material for heat recovery devoid of salt or molten salt compound and able to absorb heat produced by the absorption of hydrogen and for restoring the heat absorbed to provide heat for the hydrogen desorption. The heat storing material is a phase change material.    USE - Used as a hydrogen storage tank.    ADVANTAGE - The hydrogen storage tank is safe and easy to manufacture, allows rapid kinetics of hydrogen absorption at low cost and energy, and minimizes the variations in volume of hydrogen during storage.    DETAILED DESCRIPTION - The hydrogen storage tank comprises a hydrogen inlet and outlet contacting with a solid body for exothermic absorption and endothermic desorption of hydrogen. The solid body is formed of a compact material comprising light metal hydride and a heat conductive matrix, and related with a material for heat recovery devoid of salt or molten salt compound and able to absorb heat produced by the absorption of hydrogen and for restoring the heat absorbed to provide heat for the hydrogen desorption. The heat storing material is a phase change material, where the heat produced by the hydrogen absorption is stored in the phase change material when it passes from a first to a second phase and is restored to provide heat for hydrogen desorption when the phase change material transfers from second to first phase. The heat conductive matrix is constituted by expanded natural graphite, metal felt, non-oxide ceramics and non-oxide ceramic coated copper foams. The phase change material has a phase change temperature between a first temperature (T1) of adsorption/desorption equilibrium of the compact material at a first pressure (P1) of 1-4 bar and a second temperature (T2) of absorption/desorption equilibrium of the compact material at a second pressure (P2) of 10-20 bar. The phase change material has a heat conductivity of 100 W/mK. A tubular container is delimited by a heat conductive wall in which the solid body is arranged. The tubular containers are laid in the tank in spindle and around which the heat storage material is arranged. Each solid body has a pellet form comprising a central hole, and comprises two parts associated with a pressing unit of each part in heat contact with the container wall. The reservoir is further provided with the heat exchanger to transfer the heat from pellets to the heat storage material. A neutral gas inlet is arranged to ensure the presence of neutral gas contacting areas of heat recovery material exposed to air. The heat storage material comprises two reagents reacting with each other during an endothermic reaction using the heat for hydrogen absorption to generate a reaction product.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic side view of a hydrogen storage tank.    Inlet (21)    Outlet (22)    Porous tube (23)    Containers (30)    Wall. (31)