Non-aqueous secondary battery and method for producing the same

A non-aqueous secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte,

• the positive electrode comprising a positive electrode material mixture layer containing a lithium-containing transition metal oxide,
• the negative electrode comprising a negative electrode material mixture layer and a porous layer formed on the negative electrode material mixture layer,
• the negative electrode material mixture layer including a negative electrode material comprising a core and a carbon covering layer covering a surface of the core, the core including a material comprising silicon and oxygen at an atomic ratio x of the oxygen to the silicon of 0.5≦x≦1.5,
• the porous layer containing an insulating material unreactive with lithium,
• wherein the material comprising silicon and oxygen contains lithium at an atomic ratio y of the lithium to the silicon of 0.8≦y≦2.4 in a state in which discharge of the battery is finished.

A method for producing a non-aqueous secondary battery comprising a positive electrode including a positive electrode material mixture layer containing a lithium-containing transition metal oxide, a negative electrode and a non-aqueous electrolyte, the method comprising the steps of:

• forming a negative electrode material mixture layer including a negative electrode material comprising a core and a carbon covering layer covering a surface of the core, the core including a material comprising silicon and oxygen at an atomic ratio x of the oxygen to the silicon of 0.5≦x≦1.5,
• forming, on the negative electrode material mixture layer, a buffer layer for suppressing a reaction between lithium and the negative electrode material,
• forming a lithium-containing layer on the buffer layer by a vapor deposition method, and
• allowing the lithium contained in the lithium-containing layer to be absorbed into the negative electrode material by an electrochemical reaction.