Multiple morphology composite cathode materials providing high energy and long cycle life and cells employing the same

Abstract

Provided are electrochemically active composite materials that include a first composition optionally of LiMO(Formula I) where −0.3≤a≤0.3 and −0.3≤b≤1.3 and where M optionally includes 30 at % to 80 at % Mn and 30 at % to 75 at % Ni, the first composition formed of a polycrystalline morphology having a plurality of crystallites and a grain boundary between adjacent crystallites, the grain boundary including one or more enrichment elements, said one or more enrichment elements present at a higher atomic percentage than in an adjacent crystallite, wherein the one or more enrichment elements is selected from the group consisting of Co, Al, or both Co and Al; and a second composition optionally of LiM'O(Formula II) where −0.1≤c≤0.3 and −0.2≤d≤0.2, wherein M′ comprises Mn at about 75 at % to about 100 at %, wherein the second composition or a portion thereof optionally has a polyhedral morphology; the second composition within, on or about a surface of, or intermixed with said first composition.