The invention discloses a positive material for a
lithium ion battery and its preparation method, concretely relates to a modified
cobalt acid
lithium material and its preparation method, and relates to a
lithium ion battery containing the material. The general formula of the material is LiMxLyNwCozO2, wherein 0.001<=x<=0.1, 0.005<=y<=0,05, 0<=w<=0.05, 1-x-y-w<=z<=1, M is one or more transition metals selected from Mn, Ni, Ti, Zr, Cr, Fe, Cu, Zn, Y, Ce, Sm, Pr, La, Mo or Nb and the like, L is one or more main group
metal elements selected from Na, K, Ca, Mg, Sr, Ba, B, Ga, Sn, Sb, Bi or Al and the like; N is one or more of Li, Mn, Ni, Zr, Ti, Y, Ce, Sm, Mo, Nb, Na, K, Ca, Mg, Sr, Ba, B or Al. The material has the advantages of high specific capacity, excellent cycle performance and
heat stability, simple preparation method and easy industrialization production.