Positive electrode active material composition, positive electrode plate, battery, and electrical apparatus
A positive electrode active material composition, a positive electrode plate, a battery, and an electrical apparatus are provided. The composition includes a first positive electrode active material and a second positive electrode active material having a crystal form different from that of the first. The first active material comprises a phosphate. The particle size distribution curve of the composition exhibits at least two volume distribution peaks. The peak with the highest intensity is defined as the first peak, with a corresponding volume-based particle size Dv1. The peak with the second highest intensity is defined as the second peak, with particle size Dv2. The relative difference in particle sizes satisfies the condition 0<|Dv1−Dv2|/Dv1≤50. This dual-peak structure improves the electrochemical performance of the electrode.
1 . A positive electrode active material composition, wherein the positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material having a crystal form different from that of the first positive electrode active material, the first positive electrode active material comprises a phosphate, the second positive electrode active material comprises a layered oxide, based on a total weight of the positive electrode active material composition, a weight content of the first positive electrode active material is marked as w a , a weight content of the second positive electrode active material is marked as w b , w a is 20% or more, w b is 80% or less, a particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, a volume distribution peak with a maximal peak intensity is marked as a first peak, a volume distribution particle size corresponding to the maximal peak intensity of the first peak is marked as Dv1, a volume distribution peak with a submaximal peak intensity is marked as a second peak, and a volume distribution particle size corresponding to the maximal peak intensity of the second peak is marked as Dv2, with 0<|Dv1−Dv2|/Dv1≤50,
wherein the first positive electrode active material comprises an inner core and a shell cladding the inner core, the inner core comprises a compound represented by formula (I);
A comprises one or more elements selected from group IA, group IIA, group IIIA, group IIB, group VB and group VIB; B comprises one or more elements selected from group IA, group IIA, group IIIA, group IVA, group VA, group IIB, group IVB, group VB, group VIB and group VIII; C comprises one or more elements selected from group IIIA, group IVA, group VA and group VIA; D comprises one or more elements selected from group VIA and group VIIA; a is 0.85 to 1.15; x is 0 to 0.1; y is 0.001 to 0.999; z is 0 to 0.5; and n is 0 to 0.5,
wherein the shell comprises one or more cladding layers, each of the one or more cladding layers has ionic conductivity and/or electronic conductivity, the one or more cladding layers comprises one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride and polymer,
wherein the one or more cladding layers comprises a first cladding layer cladding the inner core and a second cladding layer cladding the first cladding layer, the first cladding layer comprises one or more selected from pyrophosphate, phosphate, oxide and boride, and the second cladding layer comprises one or more selected from carbon and doped carbon.
2 . The positive electrode active material composition according to claim 1 , wherein,
a volume distribution particle size Dv50 of the first positive electrode active material is 0.25 μm to 12.5 μm; and/or,
a volume distribution particle size Dv50 of the second positive electrode active material is 2.5 μm to 16.5 μm.
3 . The positive electrode active material composition according to claim 1 , wherein a lattice mismatch between a material of the inner core and a material of the shell is less than 10%.
4 . The positive electrode active material composition according to claim 1 , wherein, based on a total weight of the first positive electrode active material,
a manganese element content is 10 wt % to 35 wt %, optionally 13.3 wt % to 33.2 wt %, more optionally 15 wt % to 30 wt %, and further optionally 17 wt % to 20 wt %; and/or,
a phosphorus element content is 12 wt %-25 wt %, optionally 15 wt %-20 wt %, and more optionally 16.8 wt %-19.5 wt %; and/or,
a weight ratio of manganese element to phosphorus element is 0.71-1.85, optionally 0.90-1.25, and more optionally 0.95-1.20.
5 . The positive electrode active material composition according to claim 1 , wherein the one or more cladding layers each independently comprise carbon, and the carbon is a mixture of SP2-form carbon and SP3-form carbon;
optionally, a molar ratio of SP2-form carbon to SP3-form carbon in the carbon is any value within 0.07-13, more optionally any value within 0.1-10, and further optionally any value within 2.0-3.0.
6 . The positive electrode active material composition according to claim 1 , wherein,
the one or more cladding layers each independently comprise doped carbon, the doped carbon comprises a doping element, and a mass content of the doping element in the doped carbon is 30% or less; optionally, the mass content of the doping element in the doped carbon is 20% or less.
7 . The positive electrode active material composition according to claim 1 , wherein,
the one or more cladding layers each independently comprise doped carbon, the doped carbon comprises a doping element, and in the doped carbon,
the doping element is nitrogen element and/or sulfur element, and a mass content of the doping element in the doped carbon is 1% to 15%; or,
the doping element is phosphorus element, boron element and/or fluorine element, and a mass content of the doping element in the doped carbon is 0.5% to 5%;
optionally, the doping element is nitrogen, phosphorus, sulfur, boron or fluorine.
8 . The positive electrode active material composition according to claim 1 , wherein, in formula (I),
A is one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, Ga, In, Cd, V, Ta, Cr, Zn, Al, Na, K, Mg, Nb, Mo and W,
B is one or more elements selected from Rb, Cs, Be, Ca, Sr, Ba, In, Pb, Bi, Cd, Hf, Ta, Cr, Ru, Rh, Pd, Os, Ir, Pt, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge,
C is one or more elements selected from B (boron), S, Si, and N,
D is one or more elements selected from S, F, Cl and Br.
9 . The positive electrode active material composition according to claim 1 , wherein,
the pyrophosphate is M b (P 2 O 7 ) c , M is one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al, b is 1 to 4, c is 1 to 6,
the phosphate is X m (PO 4 ) q , X is one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al, m is 1 to 2, q is 1 to 4,
the oxide is M′ d O e , M′ includes one or more elements selected from Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, W, La, and Ce, d is greater than 0 and less than or equal to 2, e is greater than 0 and less than or equal to 5,
the boride is Z v B w , Z is one or more elements selected from Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb, Mn, and Al, vis 1 to 7, and w is 1 to 2,
the polymer comprises one or more selected from a polysaccharide and a polysiloxane.
10 . The positive electrode active material composition according to claim 9 , wherein when the polymer comprises the polysaccharide, the polysaccharide is one or more selected from pectin, carboxymethyl starch, hydroxypropyl starch, dextrin, cellulose ether, carboxymethyl chitosan, hydroxyethyl cellulose, carboxymethyl cellulose, carboxypropyl methyl cellulose, guar gum, sesbania gum, gum arabic, lithium alginate, sodium alginate, potassium alginate, fucoidan, agar, carrageenan, carrageenin, xanthan gum and fenugreek gum,
when the polymer comprises the polysiloxane, the polysiloxane is one or more selected from polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylvinylsiloxane, polyphenylmethylsiloxane, polymethylhydrogensiloxane, carboxyl functionalized polysiloxane, epoxy-terminated polysiloxane, methoxy-terminated polydimethylsiloxane, hydroxypropyl-terminated polydimethylsiloxane, polymethylchloropropylsiloxane, hydroxy-terminated polydimethylsiloxane, polymethyltrifluoropropylsiloxane, perfluorooctylmethylpolysiloxane, aminoethylaminopropylpolydimethylsiloxane, polyether-terminated polydimethylsiloxane, aminopropyl-branched polysiloxane, aminopropyl-terminated polydimethylsiloxane, phosphate-branched grafted polydimethylsiloxane, polyether-branched grafted polydimethylsiloxane, 1,3,5,7-octamethylcyclotetrasiloxane, 1,3,5,7-tetrahydro-1,3,5,7-tetramethylcyclotetrasiloxane, cyclopentapolydimethylsiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, cyclic polymethylvinylsiloxane, hexadecamethylcyclooctasiloxane, tetradecamethylcycloheptasiloxane, and cyclic polydimethylsiloxane.
11 . The positive electrode active material composition according to claim 9 , wherein the polysaccharide comprises a sugar unit and a substituent attached to the sugar unit, the substituent is selected from —OH, —COOH, —COOLi, —COONa, —COOK, —SO 3 H, —SO 3 Li, —SO 3 Na, —SO 3 K, —CH 2 —SO 3 H, —CH 2 —SO 3 Li, —CH 2 —SO 3 Na, —CH 2 —SO 3 K, methoxy, and ethoxy.
12 . A positive electrode plate, comprising a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, the positive electrode active material includes the positive electrode active material composition according to claim 1 , and optionally, the content of the positive electrode active material composition in the positive electrode film layer is 90 wt % to 99.5 wt %, and more optionally 95 wt % to 99.5 wt % by weight, based on a total weight of the positive electrode film layer.
13 . An electrical apparatus, comprising a battery, the battery comprising the positive electrode plate according to claim 12 .
14 . A positive electrode active material composition, wherein the positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material having a crystal form different from that of the first positive electrode active material, the first positive electrode active material comprises a phosphate, the second positive electrode active material comprises a layered oxide, based on a total weight of the positive electrode active material composition, a weight content of the first positive electrode active material is marked as w a , a weight content of the second positive electrode active material is marked as w b , w a is 20% or more, w b is 80% or less, a particle size distribution curve of the positive electrode active material composition has at least two volume distribution peaks, a volume distribution peak with a maximal peak intensity is marked as a first peak, a volume distribution particle size corresponding to the maximal peak intensity of the first peak is marked as Dv1, a volume distribution peak with a submaximal peak intensity is marked as a second peak, and a volume distribution particle size corresponding to the maximal peak intensity of the second peak is marked as Dv2, with 0<|Dv1−Dv2|/Dv1≤50,
wherein the first positive electrode active material comprises an inner core and a shell cladding the inner core, the inner core comprises a compound represented by formula (I);
A comprises one or more elements selected from group IA, group IIA, group IIIA, group IIB, group VB and group VIB; B comprises one or more elements selected from group IA, group IIA, group IIIA, group IVA, group VA, group IIB, group IVB, group VB, group VIB and group VIII; C comprises one or more elements selected from group IIIA, group IVA, group VA and group VIA; D comprises one or more elements selected from group VIA and group VIIA; a is 0.85 to 1.15; x is 0 to 0.1; y is 0.001 to 0.999; z is 0 to 0.5; and n is 0 to 0.5,
wherein the shell comprises one or more cladding layers, each of the one or more cladding layers has ionic conductivity and/or electronic conductivity, the one or more cladding layers comprises one or more selected from pyrophosphate, phosphate, carbon, doped carbon, oxide, boride and polymer,
wherein the one or more cladding layers comprises a first cladding layer cladding the inner core, a second cladding layer cladding the first cladding layer, and a third cladding layer cladding the second cladding layer, the first cladding layer comprises pyrophosphate, the second cladding layer comprises one or more selected from phosphate, oxide and boride, and the third cladding layer comprises one or more selected from carbon and doped carbon.
15 . The positive electrode active material composition according to claim 14 , wherein the one or more cladding layers further comprises a fourth cladding layer cladding the third cladding layer, and a fifth cladding layer cladding the fourth cladding layer, a cladding amount of the fourth cladding layer and a cladding amount of the fifth cladding layer are each independently 0.01 wt % to 10 wt %, based on a weight of the inner core.
16 . The positive electrode active material composition according to claim 15 , wherein a cladding amount of the fourth cladding layer and a cladding amount of the fifth cladding layer are each independently 0.01 wt % to 10 wt %, based on a weight of the inner core.