Secondary battery and method for forming electrode of secondary battery

A secondary battery comprising:

• an electrode comprising:
• a first layer including a metal material;
• and
• a second layer including silicon or a silicon compound over the first layer,
• wherein a mixed layer including the metal material and silicon is provided between the first layer and the second layer,
• wherein the silicon in the mixed layer is derived from the silicon or the silicon compound in the second layer, and
• wherein oxygen affinity of the metal material is higher than oxygen affinity of an ion which gives and receives electric charge in the secondary battery.

A method for forming an electrode of a secondary battery, comprising the steps of:

• forming a first layer including a metal material;
• forming a second layer including silicon or a silicon compound over the first layer by a plasma CVD method;
• and
• forming a mixed layer including the metal material and silicon between the first layer and the second layer by a heat treatment
• wherein the silicon in the mixed layer is derived from the silicon or the silicon compound in the second layer.

A method for forming an electrode of a secondary battery, comprising the steps of:

• forming a first layer including a metal material;
• forming a second layer including silicon or a silicon compound over the first layer by a plasma CVD method;
• and
• performing a heat treatment so that a part of the first layer reacts with a part of the second layer to form a layer of silicide of the metal material between the first layer and the second layer.