Surface chemistry and physics of deuterium retention in lithiated graphite

C. N. Taylor, Purdue University
Jean Paul Allain, Birck Nanotechnology Center, Purdue University
B. Heim, Purdue University
P. S. Krstic, Oak Ridge National Laboratory
C. H. Skinner, Princeton University
H. W. Kugel, Princeton University

Abstract

Lithium wall conditioning in TFTR, CDX-U, T-11M, and NSTX is found to yield enhanced plasma performance manifest, in part, through improved deuterium particle control. X-ray photoelectron spectroscopy (XPS) experiments examine the affect of D irradiation on lithiated graphite and show that the surface chemistry of lithiated graphite after D ion bombardment (500 eV/amu) is fundamentally different from that of non-Li conditioned graphite. Instead of simple LiD bonding seen in pure liquid Li, graphite introduces additional complexities. XPS spectra show that Li-O-D (533.0 +/- 0.6 eV) and Li-C-D (291.4 +/- 0.6 eV) bonds, for a nominal Li dose of 2 mu m, become "saturated" with D at fluences between 3.8 and 5.2 x 10(17) cm(-2). Atomistic modeling indicate that Li-O-D-C interactions may be a result of multibody effects as opposed to molecular bonding. (C) 2010 Elsevier B.V. All rights reserved.

Discipline(s)

Nanoscience and Nanotechnology