Porous carbon produced by reduction of supercritical carbon dioxide with alkali metals was used as anode material of lithium (Li) ion batteries. X-ray diffraction, field-emission scanning electron microscope, transmission electron microscope, and electron diffraction were used to characterize the structure of the products. It is shown that the products are consisted of graphite particles with relatively low graphitization and hold regular porous morphology. The porous carbon materials were evaluated as Li ion battery anodes. It exhibits a giant first discharge capacity of 1704 mAh/g at a constant current density of 0.20 mA/cm(2), while the reversible capacity decreased to 200 mAh/g. The possible origins of the irreversible capacity of porous carbons and improvement method were discussed.