Abstract: A method of making a eutectic alloy body by silicothermic reduction is provided. The method can include heating a mixture including silicon and a metal oxide comprising one or more metallic elements M and oxygen, forming a eutectic alloy melt from the mixture, and removing heat from the eutectic alloy melt, thereby forming the eutectic alloy body having a eutectic aggregation of a first phase comprising the silicon and a second phase being a silicide phase.

Abstract: Silicon eutectic alloy compositions and methods for making the same are disclosed. In one approach, a method may include using a glass carbon container to restrict contamination of the eutectic alloy melt. In an alternative approach, a method may include using a container having aluminum. The aluminum in the container may provide aluminum that is incorporated into the silicon eutectic alloy. Silicon eutectic bodies made by such methods are also disclosed.

Abstract: To carry out a rotational casting method of preparing a silicon eutectic alloy composition, silicon and one or more metallic elements M are melted together to form a eutectic alloy melt comprising the silicon and the one or more metallic elements M. A mold containing the eutectic alloy melt is rotated about a longitudinal axis thereof at a speed sufficient to form a rotating volume of the eutectic alloy melt in contact with an inner surface of the mold. Heat is directionally removed from the rotating volume of the eutectic alloy melt to directionally solidify the eutectic alloy melt, and a eutectic alloy composition, which includes the silicon, the one or more metallic elements M, and a eutectic aggregation of a first phase comprising the silicon and a second phase of formula MSi2, where the second phase is a disilicide phase, is formed.

Abstract: An electrode composition comprises a silicon powder comprising non-crystalline and crystalline silicon, where the crystalline silicon is present in the silicon powder at a concentration of no more than about 20 wt. %. An electrode for an electrochemical cell comprises an electrochemically active material comprising non-crystalline silicon and crystalline silicon, where the non-crystalline silicon and the crystalline silicon are present prior to cycling of the electrode. A method of controlling the crystallinity of a silicon powder includes heating a reactor to a temperature of no more than 650° C. and flowing a feed gas comprising silane and a carrier gas into the reactor while maintaining an internal reactor pressure of about 2 atm or less. The silane decomposes to form a silicon powder having a controlled crystallinity and comprising non-crystalline silicon.