Silicon-Based Negative Electrode for High-Capacity Lithium-Ion Batteries: "SiO"-Carbon Composite

The silicon-based materials were prepared and examined in lithium cells for high-capacity lithium-ion batteries. Among the materials examined, "SiO"-carbon composite showed remarkable improvements on capacity fading. "SiO" is composed of nanosized silicon crystallites highly dispersed in an amorphous silicon dioxide matrix. The "SiO"-carbon composite materials consisting of "SiO," graphite, and carbon fiber with carbon coatings show the smallest irreversible capacity at the first cycle and the best capacity retention among the other silicon-based materials examined, such as carbon-coated silicon, the one-to-one mixture of "SiO" and graphite, or one-to-one mixture of carbon-coated "SiO" and graphite. Capacity of more than 85% compared to capacities observed for initial ten cycles is retained after 100 cycles when the laminate-type cell with a positive electrode is examined in voltage ranging from 2.5 to 4.2 V, which meets the requirement on the negative electrodes for practical high-capacity lithium-ion batteries. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3551539]