In this paper the electrochemical characterization of a composite electrode based on β-lithium nitride (β-Li3N), iron, and synthetic graphite is reported. β-Li3N, the high pressure form of Li3N, was obtained by ballmilling a mixture of Li3N and iron metal. The electrochemical behavior of β-Li3N/Fe mixtures and pure graphite electrodes was also studied. It was found that lithium can be extracted from the β-Li3N in the presence of iron at a flat potential of 1.1 V vs. Li. A specific capacity as high as 612 mAh g-1 was recorded during the first lithium extraction. A drastic reduction of the capacity was observed on further cycling. The β-Li 3N was used as a source of lithium for the lithiation of graphite composite electrodes. A composite electrode was prepared assuming that all the lithium extracted from β-Li3N was reinserted into the graphite during cycling. Upon cycling, a progressive decrease in the β-Li 3N contribution to the electrode capacity and, concurrently, an increase in the graphite contribution were observed and after 320 cycles lithium was intercalated exclusively into the graphite. The electrode cycled for 500 cycles with a specific capacity of 315 mAh g-1 (based on the graphite weight) without any capacity loss. © 2003 The Electrochemical Society. All rights reserved.
All Science Journal Classification (ASJC) codes
- Surfaces, Coatings and Films
- Surfaces and Interfaces