Abstract: A negative electrode including a current collector, a first mix layer containing first active material particles and a binder, and a second mix layer containing second active material particles and a binder. The first mix layer is placed on the current collector. The second mix layer overlies the first mix layer. The first active material particles and the second active material particles contain Si. The second mix layer includes a plurality of pillar portions. The expansion coefficient of the second mix layer during charge is higher than the expansion coefficient of the first mix layer during charge. The electrical conductivity of the first mix layer is higher than the electrical conductivity of the second mix layer.

Abstract: An electrode material comprising a composite lithium metal oxide, which in an initial state has the formula: y[xLi2MO3.(1?x)LiM?O2].(1?y)Li1+dMn2-z-dM?zO4; wherein 0?x?1; 0.75?y<1; 0<z?2; 0?d?0.2; and z?d?2. M comprises one or more metal ions that together have an average oxidation state of +4; M? comprises one or more metal ions that together have an average oxidation state of +3; and M? comprises one or more metal ions that together with the Mn and any excess proportion of lithium, “d”, have a combined average oxidation state between +3.5 and +4. The Li1+dMn2-z-d M?zO4 component comprises a spinel structure, each of the Li2MO3 and the LiM?O2 components comprise layered structures, and at least one of M, M?, and M? comprises Co. Cells and batteries comprising the electrode material also are described.