A positive electrode material and its preparation method and application

Abstract

The present invention discloses a positive electrode material and its preparation method and application. The positive electrode material for sodium ion batteries provided by the present invention comprises the following components: an O3 type positive electrode material and a P2 type positive electrode material; the O3 type positive electrode material is a Na2O3 material doped with Sn and Zn in situ. n Ni x Zn y Fe 1 / 3 Mn 1 / 3 O2, wherein 0.95≤n≤1.02, 0<x≤0.33, x+y=0.33; the P2 type positive electrode material is Na m Ni p Mn q Mg z Ti 1‑p‑q‑z O2, wherein 0.67≤m≤0.8, 0<p≤0.25, 0.33<q≤0.6, and 0.01<z≤0.05. The high-voltage P2 / O3 mixed-phase sodium ion battery positive electrode material provided by the present invention can effectively shorten the high-voltage platform that produces irreversible phase transition, and while maintaining high capacity at a high voltage of 4.2V, it also increases the average voltage, thereby improving the stability of the electrochemical performance and high-rate performance of the positive electrode material.

Claims

1. A sodium ion battery cathode material, comprising: an O3-type cathode material and a P2-type cathode material; The O3 type positive electrode material is Sn and Zn in situ doped Na n Ni x Zn y Fe 1 / 3 Mn 1 / 3 O2, where 0.95≤n≤1.02, 0<x≤0.33, x+y=0.33; The P2 type positive electrode material is Na m Ni p Mn q Mg z Ti 1-p-q-z O2, where 0.67≤m≤0.8, 0<p≤0.25, 0.33<q≤0.6, 0.01<z≤0.05; The mass ratio of the O3 type positive electrode material to the P2 type positive electrode material is 1:(0.3-3).

2. The sodium ion battery positive electrode material according to claim 1, characterized in that The mass ratio of the O3 type positive electrode material to the P2 type positive electrode material is 3:

1.

3. The sodium ion battery positive electrode material according to claim 1 or 2, characterized in that The O3 type positive electrode material is Sn and Zn in situ doped NaNi 0.33 Fe 0.33 Mn 0.33 O2; The P2 type positive electrode material is Na 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

4. The method for preparing the sodium ion battery positive electrode material according to any one of claims 1 to 3, comprising the following steps: S1, mixing a sodium source, a nickel source, an iron source, a manganese source, a zinc source and a tin source, and calcining them to obtain an O3 type positive electrode material; S2, mixing a sodium source, a nickel source, a manganese source, a magnesium source and a titanium source, and calcining them to obtain a P2 type positive electrode material; S3. Mixing the O3 type positive electrode material with the P2 type positive electrode material to obtain a mixed-phase P2 / O3 type positive electrode material.

5. The preparation method according to claim 4, characterized in that In step S1, the mixing is performed according to any of the following conditions: 1) Mixing sodium source, nickel source, iron source, and manganese source, and then doping with zinc source and tin source; 2) Mix the sodium source, nickel source, iron source, manganese source and tin source, and then dope the zinc source.

6. The preparation method according to claim 4 or 5, characterized in that In step S1, the sodium source is selected from anhydrous sodium carbonate; The nickel source is selected from nickel oxide; The iron source is selected from ferric oxide; The manganese source is selected from one or more of trimanganese tetraoxide, manganese dioxide and manganese oxide; The zinc source is selected from zinc oxide; The tin source is selected from tin dioxide.

7. The preparation method according to any one of claims 4 to 6, characterized in that In step S1, the calcination conditions are: temperature of 900-1000°C and time of 15h; The calcination is carried out according to the following operation: first heating to 450-550°C, keeping warm for 3-7h, then heating to 900-1000°C, keeping warm for 12-18h, with a heating rate of 2°C / min; then cooling to 600-700°C, keeping warm for 0.5-3.5h, with a cooling rate of 2°C / min.

8. The preparation method according to any one of claims 4 to 7, characterized in that In step S2, the sodium source is selected from anhydrous sodium carbonate; The nickel source is selected from nickel oxide; The manganese source is selected from one or more of trimanganese tetraoxide, manganese dioxide and manganese oxide; The magnesium source is selected from magnesium oxide; The titanium source is selected from titanium dioxide.

9. The preparation method according to any one of claims 4 to 8, characterized in that In step S2, the calcination conditions are: temperature of 850-950°C and time of 15h; The calcination is carried out according to the following operation: first heating to 450-550°C, keeping warm for 3-7h, then heating to 850-950°C, keeping warm for 12-18h, with a heating rate of 2°C / min; then cooling to 600-700°C, keeping warm for 0.5h-3.5h, with a cooling rate of 2°C / min.

10. A sodium ion battery comprising a positive electrode and a negative electrode; the material of the positive electrode comprises the positive electrode material according to any one of claims 1 to 3.

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