| abstract |
A method of preparing a substantially homogenous, alkali-metal silicon clathrate composition containing the silicon clathrate M x Si 136 (3≦x≦24). The silicon clathrate is prepared by rapidly heating an alkali-metal silicide under a high vacuum to a decomposition temperature of at least 365° C. The produced silicon clathrates are in a substantially homogenous M x Si 136 phase with only small amounts of a metallic silicon clathrate phase, M y Si 46 . A method of reducing the alkali-metal content of a silicon clathrate M x Si 136 (x>0) is also provided. |