Cathode active material and lithium ion electrochemical system including the same
The present disclosure provides a cathode active material and a lithium ion electrochemical system including the same. A general formula of the cathode active material is as follows: z{xLi 2 MnO 3 *(1−x)LiRO 2 }*(1−z) Li a R′ 1-a O y , herein R and R′ independently include one or more metal ions, an oxidation valence state of the R is 3 + , and an oxidation valence state of the R′ is 2 + , herein, 0≤x≤0.25, 0<a≤0.75, 0.625≤y≤1, 0.75≤z<1.
1. A cathode active material, wherein a structure general formula of the cathode active material is as follows:
z{x Li 2 MnO 3 *(1− x )LiRO 2 }*(1− z ) Li a R′ 1-a O y ,
wherein R and R′ independently comprise one or more metal ions, an oxidation valence state of the R is 3 + , and an oxidation valence state of the R′ is 2 30 , wherein, 0≤x≤0.25, 0<a≤0.75, 0.625≤y≤1, 0.75≤z<1,
a rocksalt structure is purposefully introduced into the cathode active material by using the z{xLi 2 MnO 3 *(1−x)LiRO 2 }*(1−z) Li a R′ 1-a O y .
2. The cathode active material as claimed in claim 1 , wherein the R is independently selected from one or more of a group consist of Al, Fe, Nb, Ni, Co and Zr, the R′ is independently selected from one or more of a group consist of Ni, Mn, Co, Mg, Nb, Fe, Zn, Ti and Cu.
3. The cathode active material as claimed in claim 1 , wherein the Li 2 MnO 3 is defined as a first phase, the LiRO 2 is defined as a second phase, and the Li a R′ 1-a O y is defined as a third phase, total molar content of Mn in the first phase, R in the second phase and R′ in the third phase is TM, the R and/or the R′ comprises an element Co, and a molar content ratio of the element Co and the TM is less than or equal to 0.1.
4. The cathode active material as claimed in claim 3 , wherein the molar content ratio of the element Co and the TM is less than or equal to 0.05.
5. The cathode active material as claimed in claim 1 , wherein the Li 2 MnO 3 is defined as a first phase, the LiRO 2 is defined as a second phase, and the Li a R′ 1-a O y is defined as a third phase, the total molar content of the Mn in the first phase, the R in the second phase and the R′ in the third phase is a TM, in the cathode active material, a molar content ratio of an element Li and the TM is greater than or equal to 0.75.
6. The cathode active material as claimed in claim 5 , wherein the molar content ratio of the element Li and the TM is less than or equal to 1.5, and greater than or equal to 1.05.
7. The cathode active material as claimed in claim 1 , wherein the Li 2 MnO 3 is defined as a first phase, the LiRO 2 is defined as a second phase, and the Li a R′ 1-a O y is defined as a third phase, the total molar content of the Mn in the first phase, the R in the second phase, and the R′ in the third phase is a TM, the R and/or the R′ contains an element Ni, and a molar content ratio of the Ni and the TM is less than or equal to 0.85, and greater than or equal to 0.25.
8. The cathode active material as claimed in claim 1 , wherein the molar content ratio of the element Ni and the TM is less than or equal to 0.7, and greater than or equal to 0.3.
9. A lithium ion electrochemical system, comprising a battery, the battery has a cathode electrode, wherein the cathode electrode comprises the cathode active material as claimed in claim 1 .
10. The cathode active material as claimed in claim 2 , wherein the R is independently selected from one or more of a group consist of Al, Fe, Nb, Ni and Zr, the R′ is independently selected from one or more of a group consist of Ni, Mn, Mg, Nb, Fe, Zn, Ti and Cu.