A high-purity calcium and method of producing same are provided. The method includes performing first sublimation purification by introducing calcium starting material having a purity, excluding gas components, of 4N or less into a crucible of a sublimation vessel, subjecting the starting material to sublimation by heating at 750 C. to 800 C., and causing the product to deposit or evaporate onto the inside walls of the sublimation vessel; and then, once the calcium that has been subjected to first sublimation purification is recovered, performing second sublimation purification by introducing the recovered calcium again to the crucible to the sublimation vessel, heating the recovered calcium at 750 C. to 800 C., and causing the product to similarly deposit or evaporate on the inside walls of the sublimation vessel thereby recovering calcium having a purity of 4N5 or higher.

A method of forming a near field transducer (NFT) layer, the method including depositing a film of a primary element, the film having a film thickness and a film expanse; and implanting at least one secondary element into the primary element, wherein the NFT layer includes the film of the primary element doped with the at least one secondary element.

Embodiments relate to methods, systems And apparatus tor generating lithium from brine. The brine is heated in a first vessel to greater than 260 C. and CO.sub.2 gas is injected mixing with the brine such that the CO.sub.2/P is greater than 18 g/atm. The brine is held at greater than 18 g/atm for longer than 20 minutes so that any impurities precipitate as solids leaving only lithium ions and chlorine ions. The brine is moved to a second vessel screening out solid precipitates leaving a brine containing only chlorine and lithium. CO.sub.2 gas is injected and mixed with the brine at 260 C. so that the CO.sub.2/P is greater than 200 g/atm. The brine is held at greater than 200 g/atm for longer than 20 minutes suppressing the chlorine as dissolved ions while lithium precipitates out as lithium carbonate. The lithium carbonate precipitate is removed from the brine solution.

Embodiments relate to methods, systems And apparatus tor generating lithium from brine. The brine is heated in a first vessel to greater than 260 C. and CO.sub.2 gas is injected mixing with the brine such that the CO.sub.2/P is greater than 18 g/atm. The brine is held at greater than 18 g/atm for longer than 20 minutes so that any impurities precipitate as solids leaving only lithium ions and chlorine ions. The brine is moved to a second vessel screening out solid precipitates leaving a brine containing only chlorine and lithium. CO.sub.2 gas is injected and mixed with the brine at 260 C. so that the CO.sub.2/P is greater than 200 g/atm. The brine is held at greater than 200 g/atm for longer than 20 minutes suppressing the chlorine as dissolved ions while lithium precipitates out as lithium carbonate. The lithium carbonate precipitate is removed from the brine solution.

Disclosed is a secondary battery including a negative electrode, a positive electrode, and an electrolyte between the negative electrode and the positive electrode, wherein the negative electrode includes a negative electrode active material including: an SiFe based alloy core; a carbonaceous first coating layer disposed on the core; and a second coating layer which is disposed on the first coating layer and includes carbon nanotubes (CNTs) having an average length of about 1.0 nm to about 2.0 m.

Disclosed is a secondary battery including a negative electrode, a positive electrode, and an electrolyte between the negative electrode and the positive electrode, wherein the negative electrode includes a negative electrode active material including: an SiFe based alloy core; a carbonaceous first coating layer disposed on the core; and a second coating layer which is disposed on the first coating layer and includes carbon nanotubes (CNTs) having an average length of about 1.0 nm to about 2.0 m.

An electrode containing a clathrate compound is disclosed that is more likely to withstand load involved in repetition of penetration and desorption of, e.g., lithium ions compared to no guest substance-encapsulating silicon clathrate compounds. An electrode active material making up the electrode according to the present invention includes a clathrate compound. The clathrate compound contains a crystal lattice and a guest substance. The guest substance is encapsulated in the crystal lattice. It is preferable that the clathrate compound be a main component of the electrode active material that makes up the electrode.

An electrode containing a clathrate compound is disclosed that is more likely to withstand load involved in repetition of penetration and desorption of, e.g., lithium ions compared to no guest substance-encapsulating silicon clathrate compounds. An electrode active material making up the electrode according to the present invention includes a clathrate compound. The clathrate compound contains a crystal lattice and a guest substance. The guest substance is encapsulated in the crystal lattice. It is preferable that the clathrate compound be a main component of the electrode active material that makes up the electrode.

The invention relates to a process for the preparation of sodium-based solid compounds, such as sodium-based solid alloys and sodium-based crystalline phases by ball-milling using metallic sodium as starting material.

The invention also relates to some sodium-based crystalline P2-phases and to Na-based vanadium phosphates phases (Na.sub.(3+y)V.sub.2(PO.sub.4).sub.3) with 0<y3 and Na-based vanadium fluorophosphates phases (Na.sub.(3+z)V.sub.2(PO.sub.4).sub.2F.sub.3) with 0<z3, in particular Na.sub.4V.sub.2(PO.sub.4).sub.2F.sub.3, obtained by such a process and to their use, as active material for positive electrode, in a Na-ion battery.

The invention relates to a process for the preparation of sodium-based solid compounds, such as sodium-based solid alloys and sodium-based crystalline phases by ball-milling using metallic sodium as starting material.

The invention also relates to some sodium-based crystalline P2-phases and to Na-based vanadium phosphates phases (Na.sub.(3+y)V.sub.2(PO.sub.4).sub.3) with 0<y3 and Na-based vanadium fluorophosphates phases (Na.sub.(3+z)V.sub.2(PO.sub.4).sub.2F.sub.3) with 0<z3, in particular Na.sub.4V.sub.2(PO.sub.4).sub.2F.sub.3, obtained by such a process and to their use, as active material for positive electrode, in a Na-ion battery.