ADVANCED ANODES FOR LITHIUM ION BATTERIES FROM SILICON MODIFIED NANOFIBERS

摘要

Owing to their relatively high energy density and specific energy, lithium ion batteries are the most attractive energy storage option for applications which have weight and size constraints. However, for certain applications, such as soldier power, unmanned vehicles, directed energy weapons, and all-electric vehicles, the existing state-of-the-art technology is not sufficient to meet current needs. Advances in the anode, cathode, and electrolyte are needed. Carbon and graphite materials are commonly used as the anode in lithium ion batteries owing to their high cycle life and low cost but typically have an energy capacity of 250 mAh/g and significant irreversible charge capacity of approximately 20%. Because of increased power demand and the perceived high potential from Li-ion chemistry, a worldwide competition is underway for development of materials with enhanced energy density and power capabilities for Li-ion batteries, to enable a three-fold or higher increase in battery performance. Recent research into materials that form alloys with lithium is showing significant improvement in the energy density (ED) and specific energy (SE) of current anode materials made from carbon alone. This paper reports a method of achieving a charge capacity of 1000 mAh/g in a Si/CNF anode, a four-fold improvement in charge capacity over existing graphitic anodes for lithium ion batteries.