The effect of Al substitution on the reactivity of delithiated LiNi1/3Mn1/3Co(1/3−z)AlzO2 with non-aqueous electrolyte

The high temperature reactions between 1 M LiPF6 EC:DEC and Al-doped LiNi1/3Mn1/3Co(1/3−z)AlzO2 charged to 4.3 V were studied by accelerating rate calorimetry (ARC) and compared with those of charged LiNi1/3Mn1/3Co1/3O2 and LiMn2O4. Al substitution for Co in LiNi1/3Mn1/3Co1/3O2 improves the thermal stability. Materials with z > 0.06 are less reactive with electrolyte than spinel LiMn2O4 at all temperatures studied. The maximum self-heating rate (SHR) attained and the specific capacity decrease as the Al content increases. There is a range of compositions near z = 0.1 that show excellent promise as materials which are both safer than and more energy dense than spinel LiMn2O4.