NOVELTY - Preparation of hydrogen storage metal alloy composition comprises cooling a quantity of solid metal alloy composition to a first predetermined temperature below 0 degrees C, while soaking the solid composition for a predetermined time under an atmosphere comprising hydrogen at a predetermined pressure for hydrogen absorption into the solid composition; and heating the solid metal alloy composition from the first temperature to a second predetermined temperature at greater than or equal to 100 degrees C, while removing the hydrogen atmosphere, and reducing the pressure on the solid metal alloy composition.    USE - The method is for preparing hydrogen storage metal alloy composition for repeated absorption and desorption of hydrogen in a hydrogen storage application (claimed). The hydrogen storage metal alloy composition is useful for yielding hydrogen on demand to a fuel cell or other hydrogen consuming device for use on-board a vehicle or automotive vehicle to power it. The method is useful for titanium chromium manganese-containing Laves phase high pressure hydrogen storage alloy, AB2 type hydrogen storage material, and other metal hydride composition.    ADVANTAGE - The hydrogen storage metal alloy composition more readily stores hydrogen; and is capable of rapidly absorbing, holding, and releasing hydrogen at working temperatures, typically within 50 or above or below representative ambient temperatures of 20-30 degrees C, and holds hydrogen under hydrogen gas pressure e.g. of up to 200 bars at these temperatures. The hydrogen-containing solid metal hydride is capable of holding more hydrogen than a plain gas-filled vessel of the same volume and under the same pressure. The cooling and heating process comprises less extreme processing than prior art activation at 700 degrees C. Less energy is required and less expensive processing equipment is used. The temperature cycling method provides an industrially viable and scalable activation process to activate transition metal based hydrogen storage alloys. It eliminates the difficulties and cost of high pressure and high temperature steps by using relatively low hydrogen pressure (compared to compressed hydrogen storage at 350 bars) and low temperature cycles. The use of alloy ingots, instead of ball milled alloy powders, eliminates time and energy required for forming small micron sized particles for hydrogen storage.    DETAILED DESCRIPTION - Preparation of hydrogen storage metal alloy composition comprises:    (A) determining if a solid metal alloy composition material fails to absorb an amount of hydrogen expected to be absorbed by such metal alloy composition;    (B) cooling a quantity of the solid metal alloy composition to a first predetermined temperature below 0 degrees C, while soaking the solid composition for a predetermined time under an atmosphere comprising hydrogen at a predetermined pressure for hydrogen absorption into the solid composition;    (C) heating the solid metal alloy composition from the first temperature to a second predetermined temperature at greater than or equal to 100 degrees C, while removing the hydrogen atmosphere, and reducing the pressure on the solid metal alloy composition to promote desorption of absorbed hydrogen from the solid metal alloy composition, where first predetermined temperature, predetermined hydrogen soaking time, predetermined pressure for hydrogen absorption, and second predetermined temperature are selected for increasing the capacity of the metal alloy composition material to subsequently absorb and desorb hydrogen;    (D) determining the amount of hydrogen desorbed from the solid metal alloy composition; and    (E) optionally subjecting the solid metal alloy composition to repeated cooling, hydrogen soaking, and hydrogen absorption, followed by heating and hydrogen desorption until the determined amount of hydrogen desorbed from the solid metal alloy composition reaches a predetermined amount.