Title: Effect of Decreasing Cobalt Content on the Electrochemical Properties and Structural Stability of Li_(1-x)Ni_(y)Co_(z)Al_(0.05)O_(2) Type Cathode Materials,
Abstract: In Lithium ion batteries (LIBs), proper design of cathode materials
influences its intercalation behavior, overall cost, structural stability, and
its impact on environment. At present, the most common type of cathode
materials, NCA , has very high cobalt concentration. Since cobalt is toxic and
expensive, the existing design of cathode materials is not cost-effective, and
environmentally benign. However, these immensely important issues have not yet
been properly addressed. Therefore, we have performed density functional theory
(DFT) calculations to investigate three types of NCA cathode materials
NCA_(Co=0.15), NCA_(Co=0.10), NCA_(Co=0.05). Our results show that even if the
cobalt concentration is significantly decreased from NCA_(Co=0.15) to
NCA_(Co=0.05), variation in intercalation potential and specific capacity is
negligible. For example, in case of 50% Li concentration, voltage drop is
~0.12V while change in specific capacity is negligible. Moreover, decrease in
cobalt concentration doesn't influence the structural stability. We have also
explored the influence of sodium doping on the electrochemical and structural
properties of these three structures. Our results provide insight into the
design of cathode materials with reduced cobalt concentration, environmentally
benign, low-cost cathode materials.