| CPC H01M 4/525 (2013.01) [H01M 4/364 (2013.01); H01M 4/382 (2013.01); H01M 4/463 (2013.01); H01M 10/0525 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01)] | 20 Claims |

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1. A positive electrode active material, wherein a surface region of the positive electrode active material comprises element aluminum; and based on the weight of the positive electrode active material, a percentage of the element aluminum in the surface region is A wt %, A is 0.01 to 0.5;
wherein the surface region of the positive electrode active material further comprises element lanthanum; and based on the weight of the positive electrode active material, a percentage of the element lanthanum in the surface region is B wt %, B is 0.01 to 0.8; and
wherein an inner region of the positive electrode active material comprises element lanthanum; and based on the weight of the positive electrode active material, a percentage of the element lanthanum in the inner region is D wt %, D is 0.01 to 0.4, and 1<B/D≤5.
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