Powder material, electrode structure using the powder material, and energy storage device having the electrode structure

Abstract

A powder material which can electrochemically store and release lithium ions rapidly in a large amount is provided. In addition, an electrode structure for an energy storage device which can provide a high energy density and a high power density and has a long life, and an energy storage device using the electrode structure are provided. In a powder material which can electrochemically store and release lithium ions, the surface of particles of one of silicon metal and tin metal and an alloy of any thereof is coated by an oxide including a transition metal element selected from the group consisting of W, Ti, Mo, Nb, and V as a main component. The electrode structure includes the powder material. The battery device includes a negative electrode having the electrode structure, a lithium ion conductor, and a positive electrode, and utilizes an oxidation reaction of lithium and a reduction reaction of lithium ion.

1 .- 23 . (canceled) 
     
     
         24 . A powder material which allows lithium ions to be stored therein and released therefrom electrochemically, comprising particles of one of silicon, tin, and an alloy of at least one of silicon and tin, and an oxide covering a surface of the particles and comprising at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y. 
     
     
         25 . A powder material which allows lithium ions to be stored therein and released therefrom electrochemically, comprising an aggregate of particles each comprising a plurality of fine regions of microcrystalline or amorphous material comprising one selected from silicon, tin, and an alloy of at least one of silicon and tin, and a fine region comprising an oxide comprising at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y. 
     
     
         26 . The powder material according to  claim 24 , wherein the oxide is at least one selected from the group consisting of WO 2 , TiO 2 , MoO 2 , Nb 2 O 5 , MoO 3 , WO 3 , Li 4 Ti 5 O 12 , Li 2 Nb 2 O 5 , LiNbO 3 , LiWO 2 , LiMoO 2 , LiTi 2 O 4 , Li 2 Ti 2 O 4 , H 2 Ti 12 O 25 , Na 2 Ti 12 O 25 , VO 2 , V 6 O 13 , Al 2 O 3 , MgO, ZrO 2 , and La 2 O 3 ; those oxides having the same constituent elements as the compounds set forth above but nonstoichiometric ratios of the element of W, Ti, Mo, Nb, V, Al, Mg, Zr, and La thereof to oxygen element; and those oxides having the same elemental compositions as the compounds set forth above but having a part of one element of W, Ti, Mo, Nb, V, Al, Mg, Zr and La thereof replaced by another metal. 
     
     
         27 . The powder material according to  claim 25 , wherein the oxide is at least one selected from the group consisting of WO 2 , TiO 2 , MoO 2 , Nb 2 O 5 , MoO 3 , WO 3 , Li 4 Ti 5 O 12 , Li 2 Nb 2 O 5 , LiNbO 3 , LiWO 2 , LiMoO 2 , LiTi 2 O 4 , Li 2 Ti 2 O 4 , H 2 Ti 12 O 25 , Na 2 Ti 12 O 25 , VO 2 , V 6 O 13 , Al 2 O 3 , MgO, ZrO 2 , and La 2 O 3 ; those oxides having the same constituent elements as the compounds set forth above but nonstoichiometric ratios of the element of W, Ti, Mo, Nb, V, Al, Mg, Zr, and La thereof to oxygen element; and those oxides having the same elemental compositions as the compounds set forth above but having a part of one element of W, Ti, Mo, Nb, V, Al, Mg, Zr and La thereof replaced by another metal. 
     
     
         28 . A method of producing a powder material comprising:
 adding particles of one of silicon, tin, and an alloy of at least one of silicon and tin to a dispersion liquid having dispersed therein nanoparticles of an oxide containing at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y; and   evaporating the liquid of the dispersion liquid.   
     
     
         29 . A method of producing a powder material comprising:
 mixing particles of one of silicon, tin, and an alloy of at least one of silicon and tin with an oxide material containing at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y; and   milling the particles and the oxide material to form a composite.   
     
     
         30 . A method of producing a powder material comprising:
 mixing a powder of a source material selected from silicon, tin, and an alloy of at least one of silicon and tin with an oxide material containing at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y; and   milling the mixed source material and the oxide material to form a composite.   
     
     
         31 . A method of producing a powder material comprising:
 adding particles of one of silicon, tin, and an alloy of at least one of silicon and tin to a dispersion liquid in which nanoparticles of a compound containing at least one element selected from the group consisting of W, Ti, Mo, Nb, V, Ta, B, Ce, Al, Ba, Zr, Sr, Mg, Th, Be, La, Ca, and Y are dispersed in an organic solvent or water and performing dispersion; and   evaporating the solvent to perform drying.   
     
     
         32 . A method of producing a powder material comprising:
 mixing a powder of a source material selected from silicon, tin, and an alloy of at least one of silicon and tin with one of metal oxide fine powder and semi-metal oxide fine powder, heating the mixture up to a melting point of the source material in an inert gas atmosphere and melting the mixture to prepare a melt having the one of the metal oxide fine powder and the semi-metal oxide micro powder dispersed therein; and   (A) spraying the melt by an atomization process to form particle powder; or   (B) cooling the melt to prepare an ingot and grinding the ingot to form particle powder.   
     
     
         33 .- 35 . (canceled)