A new design of highly reversible LiNiO2: Defect formation in transition metal site

Abstract LiNiO 2 with Ni defects in the 3b sites (named “Ni defected” LiNiO 2 ) was prepared and characterized using electrochemical calorimetry. Different from conventionally prepared “Standard” LiNiO 2 , “Ni defected” LiNiO 2 exhibited high reversibility. The 1st coulombic efficiency was recorded to be 101% due to minimization from the Ni ion substitution at the Li 3a sites. The reversible capacity was 212 mAh g −1 in the 1st cycle with 87% capacity retention after 80 cycles because Li + ordering and Jahn-Teller distortion during the charge and discharge cycle were suppressed by introducing the Ni defect 3b sites. The proposed simple defect design concept introduced the development of a high capacity and highly reversible LiNiO 2 material without metal substitutions and without increasing the charge cut-off voltage.