The present invention relates to a composite material for hydrogen storage based on metal hydrides and to a method of operating a hydrogen storage system based on metal hydrides capable of releasing and absorbing hydrogen. Such hydrogen storage systems based on metal hydrides may be applicable as a fuel source for a fuel cell. The composite material for hydrogen storage comprises a powder or pellets of a hydride and a phase changing material (PCM), wherein the PCM is an encapsulated phase changing material (EPCM) which is homogeneously dispersed within the powder or pellets of the hydride.