Structural and electrochemical characteristics of Co and Al co-doped lithium nickelate cathode materials for lithium-ion batteries

LiNi0.8Co0.2-xAlxO2 (0≤x≤0.2) were prepared from LiOH·H2O and Me(OH)x (Me=Ni, Co, Al) by co-precipitation and heating at 750 deg. C for 8-24 h in oxygen flow. The optimum heating time is 16 h. XRD, SEM and various electrochemical methods were used to examine the structural and electrochemical characteristics. It is found that the doping of Al into LiNi0.8Co0.2O2 stabilizes its layered structure and greatly improves the electrochemical cycling ability. The open-circuit voltage and the discharge voltage increase slightly after minor doping, which is in agreement well with published ab initio calculations of lithium metal oxides