Electrodes comprising lithium alloyed with nanostructured silicon materials exhibit improved capacities, cycle lives, and/or cycling rates compared with similar electrodes made from bulk silicon. The electrodes do not require a conductive diluent such as carbon black. These electrodes are useful as anodes for secondary electrochemical cells, for example, batteries and electrochemical supercapacitors.
 Some aspects of the disclosed invention were made with the support of the Department of Energy of the U.S. Government under Basic Energy Sciences Grant No. DE-FG03-00ER15035. The U.S. Government may have certain rights in the invention.