POSITIVE ELECTRODE AND LITHIUM ION SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a positive electrode arranged by use of both of a lithium metal composite oxide high in Ni composition ratio, and a compound of an olivine structure, which enables the achievement of both of superior battery characteristics and excellent thermal stability.SOLUTION: A positive electrode comprises a positive electrode active material layer including a lithium nickel composite oxide of a lamellar rock-salt structure, which is represented by LiNiCoMnDO(0.5≤b) and a lithium metal phosphate compound in which LiMPOof an olivine structure is coated with carbon. The lithium nickel composite oxide is smaller than the lithium metal phosphate compound in average particle diameter. Further, the lithium nickel composite oxide is larger than the lithium metal phosphate compound in volume resistance.SELECTED DRAWING: None 【課題】Ｎｉ組成比が高いリチウム金属複合酸化物とオリビン構造の化合物とを併用した正極であって、優れた電池特性及び優れた熱安定性を両立するものを提供する。【解決手段】層状岩塩構造のＬｉａＮｉｂＣｏｃＭｎｄＤｅＯｆ(０．５≦ｂ)で表されるリチウムニッケル複合酸化物と、オリビン構造のＬｉＭｈＰＯ４を炭素で被覆したリチウム金属リン酸化合物とを含む正極活物質層を具備する正極であって、前記リチウムニッケル複合酸化物の平均粒子径が、前記リチウム金属リン酸化合物の平均粒子径よりも小さく、かつ、前記リチウムニッケル複合酸化物の体積抵抗が、前記リチウム金属リン酸化合物の体積抵抗よりも大きいことを特徴とする正極。【選択図】なし