Provided is a novel production method for producing silicon clathrate II. In the production method for producing silicon clathrate II, in a reaction system in which a NaSi alloy containing Na and Si and an Na getter agent coexist so as not to be in contact with each other, the NaSi alloy is heated and Na evaporated from the NaSi alloy is thus caused to react with the Na getter agent to reduce an amount of Na in the NaSi alloy.

Provided is a negative electrode active material that contains silicon clathrate II and that is suitable for a negative electrode of a lithium ion secondary battery. The negative electrode active material includes a silicon material in which silicon clathrate II represented by composition formula Na.sub.xSi.sub.136 (0x10) is contained and a volume of a pore having a diameter of not greater than 100 nm is not less than 0.025 cm.sup.3/g.

Provided is a negative electrode active material that contains silicon clathrate II and that is suitable for a negative electrode of a lithium ion secondary battery. The negative electrode active material includes a silicon material in which silicon clathrate II represented by composition formula Na.sub.xSi.sub.136 (0x10) is contained and a volume of a pore having a diameter of not greater than 100 nm is not less than 0.025 cm.sup.3/g.

The present disclosure provides a negative electrode material, a preparation method thereof, and an all-solid-state lithium battery. The negative electrode material includes a core and an amorphous lithium-silicon alloy layer cladding the core. The core includes a glassy solid electrolyte and amorphous lithium-silicon alloy particles dispersed in the glassy solid electrolyte. The material of the amorphous lithium-silicon alloy particles is Li.sub.xSi, 0<x4.4. The material of the amorphous lithium-silicon alloy layer is Li.sub.ySi, 0<y4.4.

The present disclosure provides a negative electrode material, a preparation method thereof, and an all-solid-state lithium battery. The negative electrode material includes a core and an amorphous lithium-silicon alloy layer cladding the core. The core includes a glassy solid electrolyte and amorphous lithium-silicon alloy particles dispersed in the glassy solid electrolyte. The material of the amorphous lithium-silicon alloy particles is Li.sub.xSi, 0<x4.4. The material of the amorphous lithium-silicon alloy layer is Li.sub.ySi, 0<y4.4.

A process for producing lithium aluminum ingots is provided. In one embodiment, the process includes preparing a master alloy comprising about 70 to 90 percent by weight lithium and 10 to 30 percent by weight aluminum and dissolving the master alloy in lithium at a temperature of from about 230 C. to 330 C. to provide a lithium aluminum ingot having between about 1500 to 2500 ppm by weight aluminum. In another embodiment, the process may produce a lithium aluminum ingot having about 0.001 to about 1.0 percent aluminum.

A process for producing lithium aluminum ingots is provided. In one embodiment, the process includes preparing a master alloy comprising about 70 to 90 percent by weight lithium and 10 to 30 percent by weight aluminum and dissolving the master alloy in lithium at a temperature of from about 230 C. to 330 C. to provide a lithium aluminum ingot having between about 1500 to 2500 ppm by weight aluminum. In another embodiment, the process may produce a lithium aluminum ingot having about 0.001 to about 1.0 percent aluminum.

A magnesium-lithium-based alloy contains Mg, Li, and Al, and a sum of a content of the Mg and a content of the Li is 90% by mass or more. The magnesium-lithium-based alloy contains Ge.

A magnesium-lithium-based alloy contains Mg, Li, and Al, and a sum of a content of the Mg and a content of the Li is 90% by mass or more. The magnesium-lithium-based alloy contains Ge.

Process for preparing a metal containing layer, the process comprising (i) at least one step of co-vaporization, at a pressure which is lower than 10.sup.2 Pa, of a) at least one first metal selected from Li, Na, K, Rb and Cs and b) at least one second metal selected Mg, Zn, Hg, Cd and Te from a metal alloy provided in a first vaporization source which is heated to a temperature between 100 C. and 600 C., and (ii) at least one subsequent step of deposition of the first metal on a surface having a temperature which is below the temperature of the first vaporization source, wherein in step (i), the alloy is provided at least partly in form of a homogeneous phase comprising the first metal and the second metal, electronic devices comprising such materials and process for preparing the same.