POSITIVE ELECTRODE ACTIVE MATERIAL FOR SODIUM ION BATTERY, SODIUM ION BATTERY MADE FROM SAME, BATTERY MODULE, BATTERY PACK AND APPARATUS
The present disclosure relates to a positive electrode active material for a sodium ion battery, a sodium ion battery made from the same, a battery module, a battery pack and an apparatus. Specifically, the positive electrode active material for a sodium ion battery mainly includes an O3-phase layered metal oxide having the following molecular formula: Na a M b Ni c Fe d Mn e O 2±δ (Formula I), in which M is a metal cation different from Ni, Fe and Mn; 0.67<a<1.1; 0<b<0.25, optionally 0.05<b<0.15; 0<c<0.3, optionally 0.05<c<0.25; 0<b+c<0.55, 0.45<d+e<1, and b+c+d+e=1; and 0≤δ≤0.1, wherein the metal cation is at least one selected from Li + , Cu 2+ , Zn 2+ , Co 2+ and Ti 4+ .
1 . A positive electrode active material for a sodium ion battery, mainly comprising an O3-phase layered metal oxide having the following molecular formula:
Na a M b Ni c Fe d Mn e O 2±δ (Formula I)
in which
M is a metal cation different from Ni, Fe and Mn; 0.67<a<1.1; 0<b<0.25, optionally 0.05<b<0.15; 0<c<0.3, optionally 0.05<c<0.25; 0<b+c<0.55, 0.45<d+e<1, and b+c+d+e=1; and 0≤δ≤0.1,
wherein the metal cation is at least one selected from Li + , Cu 2+ , Zn 2+ , Co 2+ and Ti 4+ .
2 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein the O3-phase layered metal oxide has a ratio of I(003)/I(104) of ≥0.62, optionally between 0.67 and 1.5, in an X-ray diffraction spectrum, wherein I(003) denotes a peak intensity of the (003) crystal plane of the O3-phase layered metal oxide, while I(104) denotes a peak intensity of the (104) crystal plane of the O3-phase layered metal oxide, and I(003)/I(104) reflects an antisite defect of sodium metal cation in the O3-phase layered metal oxide.
3 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein the O3-phase layered metal oxide has a hexagonal crystal system with a space group specified by R3m, wherein a ratio of crystal lattice parameter c to crystal lattice parameter a is greater than or equal to 5, optionally greater than or equal to 5.5.
4 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein the O3-phase layered metal oxide has a ratio of I(003)/I(104) of ≥0.62, optionally between 0 . 67 and 1.5, in the X-ray diffraction spectrum, and the O3-phase layered metal oxide has a hexagonal crystal system with a space group specified by R3m, wherein a ratio of crystal lattice parameter c to crystal lattice parameter a is greater than or equal to 5, optionally greater than or equal to 5.5.
5 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein primary particles of the O3-phase layered metal oxide have a flaky structure.
6 . The positive electrode active material for a sodium ion battery according to claim 5 , wherein the primary particles have a grain size between 0.05 and 15 microns, optionally between 0.1 and 5 microns.
7 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein the positive electrode active material has a compacted density between 1.5 g/cm 3 and 4.5 g/cm 3 , optionally between 2.5 g/cm 3 and 4 g/cm 3 , under a pressure of 8 tons.
8 . The positive electrode active material for a sodium ion battery according to claim 1 , wherein the positive electrode active material is obtained by the following steps:
i) coprecipitating a Ni source and a Mn source in the presence of a complexing agent and a precipitating agent to obtain a Ni—Mn metal salt percuros, and
ii) carrying out a solid phase sintering to the Ni—Mn metal salt precursor from the step i) together with a Na source, a Fe source and an M source, so as to obtain the positive electrode active material comprising the O3-phase layered metal oxide.
9 . The positive electrode active material for a sodium ion battery according to claim 8 , wherein the sintering is carried out at a temperature of 850° C. to 920° C., preferably 890° C. to 910° C., more preferably 895° C. to 905° C., and most preferably 900° C.
10 . The positive electrode active material for a sodium ion battery according to claim 8 , wherein the sintering is carried out for a period of from 15 to 25 hours, preferably from 17 to 22 hours, more preferably from 19 to 21 hours, and most preferably 20 hours.
11 . A sodium ion battery, comprising a positive electrode plate, a negative electrode plate, a separator disposed between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector, and a positive electrode active material layer disposed on at least one side of the positive electrode current collector, wherein the positive electrode active material is the positive electrode active material according to claim 1 , and wherein the battery has a charge cut-off voltage of 4.2 V or higher.
12 . The sodium ion battery according to claim 11 , wherein the battery has an initial specific discharge capacity of 120 mAh/g at a voltage of 2.0 V to 4.2 V, and a capacity retention of 87% or higher after 100 cycles at 1 C.
13 . A sodium ion battery, comprising a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector, and a positive electrode active material layer disposed on at least one side of the positive electrode current collector, wherein the positive electrode active material is the positive electrode active material according to claim 1 , and wherein the battery has a charge cut-off voltage of 4.5 V or higher.
14 . The sodium ion battery according to claim 13 , wherein the battery has an initial specific discharge capacity of 150 mAh/g at a voltage of 2.0 V to 4.5 V, and a capacity retention of 80% or higher after 100 cycles at 1 C.