Structural observation of energy storage materials prepared by MA

Mechanical alloying (MA) was employed to synthesize hydrogen storage materials and cell materials as anodes of secondary lithium-ion batteries. Amorphous MgNi alloy was prepared by MA. The structures of dilutely and fully deuterated MgNi alloys (MgNiD0.1, MgNiD1.6) were observed using a combination of X-ray and neutron diffractions. The radial distribution functions RDF(r) of the amorphous MgNiDx alloys provided us information that deuterium atom occupies the tetrahedral site composed of nearly 2Mg(2)Ni. Hexagonal graphite was found out to absorb deuterium during the MA process, It changed into the nano-crystalline one after milling. Two types of the location of deuterium atoms for CD0.661 powder were found in RDF(r) observed by neutron diffraction. One is the C-D covalent bond and the other is due to deuterium located between layers of the graphite. Lithium-graphite intercalation compound was obtained from graphite and lithium mixed powders by MA. The short-range structure around a Li atom was observed by using the advantage of neutron diffraction. The coordination number of the C-Li correlation indicates the formation of LiC3.1 intercalation compound. (C) 2002 Elsevier Science B.V. All rights reserved.