Hydrogen storage systems and method of making them

A method of making an alkali metal-carbon composition, said method comprising

• preparing a precursor mixture comprising a carbon material including graphite carbon, and one or more alkali metals selected from the group consisting of lithium, sodium and potassium under an atmosphere that is substantially inert to said alkali metal, the amount of said carbon material exceeding, on an atomic ratio basis, twelve parts of carbon per atom of lithium or sodium and twenty-four parts of carbon per atom of potassium,
• reacting said precursor mixture under such an atmosphere and at a temperature and pressure to form a precursor product comprising layers of carbon atoms with intercalated alkali metal atoms,
• treating said precursor product with alcohol to remove any unreacted alkali metal,
• preparing a second mixture comprising an additional amount of said one or more alkali metals, and said precursor product under an atmosphere that is substantially inert to said alkali metal, the amount of said additional metal being sufficient to reduce the atomic proportion of carbon to alkali metal to a value in the range of six to twelve parts carbon per atom of lithium or sodium and eight to twenty-four parts of carbon per potassium atom, and
• reacting said second mixture under such an atmosphere to form a reaction product comprising layers of carbon atoms with intercalated alkali metal atoms and further characterized by an absence of x-ray diffraction maxima for said carbon and said alkali metal.