A negative electrode material for a nonaqueous electrolyte secondary
battery having a high discharge capacity and a good cycle life is made
from alloy particles having an average particle diameter of 0.1-50 .mu.m
and including Si phase grains 40 and a phase of a solid solution or an
intermetallic compound of Si and other element selected from Group 2A
elements, transition elements, Group 3B elements, and Group 4B elements
from the long form periodic table (for example, an NiSi.sub.2 phase 42 and
an [NiSi.sub.2 +NiSi] phase 41) at least partially enveloping the Si phase
grains. 5-99 wt % of this material is Si phase grains. The alloy particles
can be manufactured by rapid solidification (such as atomization or roller
quenching) of a melt including Si and the other element, or by adhering
the other element to Si powder by electroless plating or mechanical
alloying and then performing heat treatment. Even if rapid solidification
is carried out, a negative electrode material having a good discharge
capacity and cycle life is obtained without heat treatment.
