A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode material will be able to accommodate significant volume changes expected upon alloying and de-alloying with lithium. The mesoporosity will be created without the aid of a surfactant template using a novel high volume synthetic process. The anode composite based on this material is designed to have a reversible Li-ion capacity exceeding 600 mAh/g or nearly twice that obtainable with graphite anodes; indeed much higher capacities could be practically attainable. Coupled with our advanced polymer electrolyte and a high voltage cathode, we expect a fully developed battery to have a specific energy of >150 Wh/Kg, and energy density of >300 Wh/l and the capability to produce >1000 deep charge/discharge cycles and thus makes it very desirable for space power applications of NASA. The work plan will include the materials synthesis, fabrication of electrode structures, evaluating rechargeability and cyclability of the anode, and reporting results.