CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2014-0158903, filed on Nov. 14, 2014, in the Korean Intellectual Property Office, and entitled: “Negative Active Material and Lithium Battery Including The Same,” is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

One or more exemplary embodiments relate to negative active materials and lithium batteries including the negative active materials.

2. Description of the Related Art

Lithium secondary batteries that may be used in portable electronic communication devices such as personal digital assistants (PDAs), mobile phones, and laptop computers, electric bicycles, and electric automobiles may have a discharge voltage greater than, e.g., at least twice those of, comparative batteries, and the lithium secondary batteries may have high energy density.

SUMMARY

Embodiments may be realized by providing a negative active material, including a non-carbonaceous core allowing doping or undoping of lithium ion; and a double coating layer formed on at least one portion of a surface of the non-carbonaceous core and including a first coating layer including a metal and a second coating layer including a metal oxide or a metal nitride.

The first coating layer may be disposed on the surface of the non-carbonaceous core, and the second coating layer may be disposed on the first coating layer.

The metal in the first coating layer may include one or more of Li, Al, Sn, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Nb, Ba, Lu, Hf, Ta, or Lanthanum group elements.

The metal oxide or metal nitride in the second coating layer may include an oxide or nitride of one or more of Li, Al, Sn, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Nb, Ba, Lu, Hf, Ta, or Lanthanum group elements.

The metal oxide or metal nitride in the second coating layer may include an oxide or nitride of the metal in the first coating layer.

The first coating layer may include Li, and the second coating layer may include Li2O.

A thickness of the first coating layer may be in a range of about 0.1 nm to about 0.1 μm.

A thickness of the second coating layer may be in a range of about 0.1 nm to about 1 μm.

The non-carbonaceous core may include Si; SiOx(0<x<2); a Si—Z alloy, where Z is an alkali metal, an alkali earth metal, an element of Groups XIII to XVI, a transition metal, a rare earth element, or a combination thereof except for Si, Sn, or SnO2, the Si—Z alloy having a Si-based alloy structure including an inactive matrix including Si and one or more of an element of Groups II to XIV except for Si, and active Si nanoparticles dispersed in the inactive matrix; a Sn—Z alloy, where Z is an alkali metal, an alkali earth metal, an element of Groups XIII to XVI, a transition metal, a rare earth element, or a combination thereof except for Sn; or a combination thereof.

An average particle diameter of the non-carbonaceous core may be in a range of about 1 nm to about 50 μm.

The negative active material may further include a crystalline carbonaceous material.

The non-carbonaceous core coated with the double coating layer and the crystalline carbonaceous material may be mixed in a weight ratio of about 0.99:0.01 to about 0.01:0.99.

Embodiments may be realized by providing a lithium battery, including a negative electrode including the presently disclosed negative active material; a positive electrode opposite the negative electrode; and an electrolyte between the negative electrode and the positive electrode.

