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 (MgNiD_0.1, MgNiD_1.6) were observed using a combination of X-ray and neutron diffractions. The radial distribution functions RDF(r) of the amorphous MgNiD_x alloys provided us information that deuterium atom occupies the tetrahedral site composed of nearly 2Mg₂Ni. 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 CD_0.661 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 LiC_3.1 intercalation compound.