| CPC H01M 4/505 (2013.01) [H01M 4/364 (2013.01); H01M 4/525 (2013.01); H01M 4/5825 (2013.01); H01M 4/583 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)] | 26 Claims | 

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               1. An electrochemically active composite material comprising: 
            a first particle, which is a polycrystalline secondary particle defined by a first composition comprising Li1+aMO2+b (Formula I) where −0.3≤a≤0.3 and −0.3≤b≤1.3 and where M comprises Mn at 20 at % to 80 at % and Ni at 30 at % to 75 at %, said first composition formed of a polycrystalline morphology comprising a plurality of crystallites and a grain boundary between adjacent crystallites, said grain boundary with a layered α-NaFeO2-type structure, a cubic structure, or combination thereof and defined by composition Li1+aM″O2+b (Formula III) where −0.3≤a≤0.3 and −0.3≤b≤1.3, wherein M″ comprises one or more enrichment elements in at least a portion thereof, said one or more enrichment elements present at a higher atomic percentage in said portion than in M of an adjacent crystallite, and wherein said one or more enrichment elements is selected from the group consisting of Co, Al, or both Co and Al; and 
                a second particle defined by a second composition comprising Li1+cM′2O4+d (Formula II) where −0.1≤c≤0.3 and −0.2≤d≤0.2, wherein M′ comprises Mn at 75 at % to 100 at %, wherein said second composition or a portion thereof comprises a spinel structure and in the form of a three dimensional polyhedron, and wherein said second particle on or about a surface of the first particle. 
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