Synthesis and anode behavior of lithium storage intermetallic compounds with various crystallinities

An anode active material, Mg2.0Ge, was synthesized using mechanical alloying (MA). Electrochemical performance of the compounds having different crystallinities was examined. It was found that the first discharge capacity of the Mg2.0Ge with a 90% crystallinity (MA treatment for 25 h) was ca. 320 mA h g(-1). The lattice expansion at the insertion of Li was decreased with decreasing crystallinity, suggesting the prolongation of cycle life. On the other hand, the discharge capacity of Mg2.0Ge with the lower crystallinity (MA treatment for 100 h) showed an insignificant value, being ca. 25 mA h g(-1), but the cycle dependence of capacities was favorable. (C) 1999 Elsevier Science S.A. All rights reserved.