Researchers have been trying everything they can think of to eke more performance out of lithium-ion batteries. One approach has been to increase the mobility of lithium ions between the battery's electrodes. Another tack is to replace the graphitic anode materials into which lithium intercalates in most of today's lithium-ion batteries with metallic alloys that can host more ions in the same amount of space and therefore accommodate more of the current-generating electrochemical reaction between the anode and cathode. Early last year, for example, Sony unveiled its Nexelion line of lithium-ion batteries, which includes an anode made of an amorphous tin-based metal alloyed with cobalt, carbon, and other ingredients. The quest for practical alloys that can work well as an anode in lithium-ion batteries has been tough because the materials most often expand and contract dramatically as lithium ions move in and out.
by Ivan Amato |
February 13, 2006