Unveiling the crystallographic effect of Li(Ni0.90Co0.09Al0.01)O2 with a high Ni content on the high capacity generation in Li-ion battery

Abstract

Li(Ni0.90Co0.09Al0.01)O2 with a high Ni content is one of the attractive cathode materials for a Li-ion battery due to the generation of a high capacity at 0.1C that is 246 mAh g-1 for charging and 225 mAh g-1 for discharging. The crystallographic effect on generating the high capacity is provided with in-situ X-ray diffraction of Li(Ni0.90Co0.09Al0.01)O2. Peaks in X-ray diffraction differently alter at final stage during charging according to C-rate and temperature. The movement of Li-ion in the material is obstructed under high C-rate or low temperature conditions. The reason for the delay of Li-ion mobility is revealed with complementary crystallographic analysis of X-ray diffraction, extended X-ray absorption fine structure, Pair distribution function, and transmission electron microscope. The atomic distances distinctly vary by the kind of atom during charging and discharging. The strain and size of the crystal in the material anisotropically change during charging. Anisotropic alteration induces cracks, voids, and atomic distortions inside the particle of Li(Ni0.90Co0.09Al0.01)O2. Our results establish the chemo-mechanical behavior by the capacity generation of Li(Ni0.90Co0.09Al0.01)O2. Finally, the removal of the anisotropic state inside a cathode material is extremely crucial to creating enhancement of capacity and lifetime for a Li-ion battery.