Anode active material including a multilayer metal nanotube, anode including the anode active material, lithium battery including the anode, and method of preparing the anode active material

Abstract

An anode active material, an anode including the anode active material, a lithium battery including the anode, and a method of preparing the anode active material. The anode active material includes: a multilayer metal nanotube including: an inner layer; and an outer layer on the inner layer, wherein the inner layer includes a first metal having an atomic number equal to 13 or higher, and the outer layer includes a second metal different from the first metal.

What is claimed is: 
     
         1 . An anode active material comprising:
 a multilayer metal nanotube comprising:
 an inner metal layer; and 
 an outer metal layer which is different from the inner metal layer and is on the inner layer. 
   
     
     
         2 . The anode active material of  claim 1 , wherein the inner metal layer comprises a first metal having an atomic number equal to 13 or higher. 
     
     
         3 . The anode active material of  claim 2 , wherein the outer metal layer comprises a second metal different from the first metal. 
     
     
         4 . The anode active material of  claim 3 , wherein the second metal has a resistivity which is less than a resistivity of the first metal. 
     
     
         5 . The anode active material of  claim 3 , wherein the second metal has a lithium ion diffusivity which is greater than a lithium ion diffusivity of the first metal. 
     
     
         6 . The anode active material of  claim 3 , wherein the second metal has a volume expansion during charging which is less than a volume expansion during charging of the first metal. 
     
     
         7 . The anode active material of  claim 2 , wherein the first metal is at least one selected from silicon, germanium, antimony, tin, aluminum, zinc, silver, gold, platinum, molybdenum, tungsten, and an alloy thereof. 
     
     
         8 . The anode active material of  claim 2 , wherein the first metal is a Group 14 element. 
     
     
         9 . The anode active material of  claim 3 , wherein the second metal is at least one selected from germanium, antimony, tin, aluminum, zinc, silver, gold, platinum, molybdenum, tungsten, and an alloy thereof. 
     
     
         10 . The anode active material of  claim 3 , wherein the outer layer comprises a composite of the first metal and the second metal. 
     
     
         11 . The anode active material of  claim 1 , wherein the inner layer is crystalline and the outer layer is amorphous. 
     
     
         12 . The anode active material of  claim 1 , wherein at least one of the inner layer and the outer layer further comprises a dopant. 
     
     
         13 . The anode active material of  claim 12 , wherein the dopant is a Group 13 element or a Group 15 element. 
     
     
         14 . The anode active material of  claim 1 , further comprising at least one layer disposed between the inner layer and the outer layer. 
     
     
         15 . The anode active material of  claim 1 , wherein a wall thickness of the metal nanotube is about 10 nanometers to about 200 nanometers. 
     
     
         16 . The anode active material of  claim 1 , wherein a thickness of the inner layer is about 5 nanometers to about 100 nanometers. 
     
     
         17 . The anode active material of  claim 1 , wherein a thickness of the outer layer is about 5 nanometers to about 100 nanometers. 
     
     
         18 . The anode active material of  claim 1 , wherein an outer diameter of the metal nanotube is about 30 nanometers to about 400 nanometers. 
     
     
         19 . The anode active material of  claim 1 , wherein an inner diameter of the metal nanotube is about 20 nanometers to about 200 nanometers. 
     
     
         20 . The anode active material of  claim 1 , wherein a length of the metal nanotube is about 1 μm to about 50 μm. 
     
     
         21 . The anode active material of  claim 1 , wherein an end of the metal nanotube is closed. 
     
     
         22 . An anode comprising the anode active material according to  claim 1 . 
     
     
         23 . A lithium battery comprising the anode of  claim 22 .