Abstract: Provided are a positive electrode active material and a preparation method thereof, a positive electrode plate, a secondary battery, a battery module, a battery pack, and an electric apparatus. The positive electrode active material includes a core and a shell layer enveloping the core, the core having a chemical formula LiaAxMn1-yByP1-zCzO4-nDn, where A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, C includes one or more elements selected from B, S, Si, and N, and D includes one or more elements selected from S, F, Cl, and Br; and the shell layer is a doped carbon layer, a doping element in the doped carbon layer including any one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine.

Abstract: Provided are a positive electrode active material, a method for the preparation thereof and a positive electrode plate, a secondary battery and an electrical device. The positive electrode active material having a core-shell structure, including a core and a shell cladding the core, the core has a chemical formula of LimAxMn1-yByP1-zCzO4-nDn, the shell includes a first cladding layer cladding the core, a second cladding layer cladding the first cladding layer and a third cladding layer cladding the second cladding layer, the first cladding layer includes crystalline pyrophosphates LiaMP2O7 and/or Mb(P2O7)c, the second cladding layer includes crystalline phosphate XPO4, and the third cladding layer is carbon. The positive electrode active material of the present application enables the secondary battery and electrical device to have a relatively high energy density, and good cycling performance, rate performance and safety performance.

Abstract: The present application provides a positive electrode active material, a method for the preparation thereof and a positive electrode plate, a secondary battery and an electrical device containing the same. The positive electrode active material having a core-shell structure, comprising a core and a shell covering the core, wherein the core has a chemical formula of LiaAxMn1-yByP1-zCzO4-nDn, the shell comprises a first cladding layer covering the core, and a second cladding layer covering the first cladding layer, wherein the first cladding layer comprises pyrophosphate MP2O7 and phosphate XPO4, and the second cladding layer comprises carbon. The positive electrode active material of the present application enables the secondary battery and electrical device to have a relatively high energy density, and good cycling performance, rate performance and safety performance.

Abstract: Provided are a positive electrode active material and a preparation method thereof, a positive electrode plate, a secondary battery, a battery module, a battery pack, and an electric apparatus. The positive electrode active material includes a core including Li1+xMn1?yAyP1?z,RzO4, a first coating layer enveloping the core and containing a crystalline pyrophosphate LiaMP2O7 and/or Mb(P2O7)e, a second coating layer enveloping the first coating layer and containing a crystalline oxide M?dOe, and a third coating layer enveloping the second coating layer and containing carbon. The positive electrode active material of this application can reduce Li/Mn anti-site defects generated, reduce dissolving-out amount of manganese, lower the lattice change rate, increase the capacity of the secondary battery, and improve the cycling performance, high-temperature storage performance, and safety performance of the secondary battery.

Abstract: A positive electrode active material has LiMPO4, wherein M includes Mn and a non-Mn element, and the non-Mn element satisfies at least one of the following conditions: the ionic radius of the non-Mn element being denoted as a, and the ionic radius of manganese element being denoted as b, |a?b|/b is not greater than 10%; the valence alternation voltage of the non-Mn element being denoted as U, 2 V<U<5.5 V; the chemical activity of a chemical bond formed by the non-Mn element and O is not less than that of a P—O bond; and the highest valence of the non-Mn element is not greater than 6.

Abstract: A positive electrode active material has an inner core and a shell coating the inner core, wherein the inner core comprises at least one of a ternary material, dLi2MnO3·(1?d)LiMO2 and LiMPO4, where 0<d<1, and M includes one or more selected from Fe, Ni, Co, and Mn; and the shell contains a crystalline inorganic substance having a full width at half maximum of the main peak of 0-3° as measured by means of X-ray diffraction, and the crystalline inorganic substance includes one or more selected from a metal oxide and an inorganic salt.

Abstract: Provided are a positive electrode active material with a core-shell structure, a preparation method of positive electrode active material, a positive electrode plate, a secondary battery, a battery module, a battery pack, and an electric apparatus. The positive electrode active material includes a core containing LimAxMn1-yByP1-zCzO4-nDn, a first coating layer covering the core and containing a crystalline pyrophosphate MaP2O7 and an oxide M?bOc, and a second coating layer covering the first coating layer. The positive electrode active material in this application can reduce the generation of Li/Mn antisite defects, reduce the dissolution of manganese, and decrease the lattice change rate, increasing the capacity of the secondary battery and improving the cycling performance, high-temperature storage performance, and safety performance of the secondary battery.

Abstract: A positive electrode active material includes a core containing Li1+xMn1yAyP1?zRzO4, a first coating layer covering the core and containing a crystalline pyrophosphate MaP2O7 and a crystalline oxide M?bOc, and a second coating layer covering the first coating layer.

Abstract: A positive electrode active material includes LiaAxMn1-yByP1-zCzO4-nDn. A includes one or more selected from group IA, group IIA, group IIIA, group IIB, group VB, and group VIB. B includes one or more selected from group IA, group IIA, group IIIA, group IVA, group VA, group IIB, group IVB, group VB, group VIB, and group VIII. C includes one or more selected from group IIIA, group IVA, group VA and group VIA. D includes one or more selected from group VIA and group VIIA. a is selected from 0.85 to 1.15. x is selected from 0 to 0.1. y is selected from 0.001 to 0.999. z is selected from 0 to 0.5. n is selected from 0 to 0.5.