In some embodiments, the electrodes may have independent chemical structures. For example, the first electrode and the second electrode independently comprise metal containing compositions. Example metal containing compositions include, but are not limited to, metal oxides, metal hydrides, metal sulfides, metal nitrides, metal halides, metal composites, intermetallic compounds, metalloid alloys, or metallic compositions, such as base metals or alloys. Example metals in metal containing compositions include transition metals and specifically one or more of Mn, Zn, Fe, Co, Ni, Cu, Mo, Tc, Ru, V, Bi, Ti, Rh, Pd, Ag, Au, W, Re, Os, La, Na, K, Rb, Cs, Ir, or Pt. In some embodiments, an electrode comprises the same metal and/or metal containing composition as another electrode. In other embodiments, an electrode comprises a different metal and/or metal containing compositions as another electrode. Optionally, an electrode comprises a metal, metal oxide, a metalloid, and/or a metalloid alloy (i.e., a composition including a metal and a metalloid). Example metalloids include boron, silicon, germanium, arsenic, antimony, carbon, aluminum, and selenium. Optionally, electrodes comprise alternating layers of active material and another material, such as amorphous carbon.