Active material for lithium secondary battery composite electrode for improving output and lithium secondary battery including the active material

A composite electrode comprising:

• a current collector;
• and
• a single layer disposed on the current collector, wherein the single layer comprises a mixture of secondary particles of a first active material and particles of a second active material,
• wherein the secondary particles comprise primary particles of the first active material and a conductive agent, wherein the primary particles have a particle size ranging from about 5 nm to about 200 nm, wherein the conductive agent is present on the surface of and inside of the secondary particles, and wherein the conductive agent is included in an amount range of 0.5 wt % to 5 wt % based on a total weight of the secondary particles,
• wherein the particles of the second active material consist essentially of primary particles of the second active material having a particle size ranging from about 5 μm to about 20 μm,
• wherein the secondary particles of the first active material have a particle size uniform with the particles of the second active material,
• wherein the secondary particles are present in an amount ranging from about 30 wt % to about 80 wt % of a total amount of the first active material in the composite electrode,
• wherein the first active material is LiFePO4, and
• wherein the second active material is ternary lithium-containing metal oxide expressed as Chemical Formula 2:
• LiNixMnyCo1-x-yO2, 0<x<0.5, 0<y<0.5 [Chemical Formula 2].