Improving the electrochemical performance of a Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 cathode for lithium-ion batteries

In this report, Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 was prepared as the cathode for lithium-ion batteries through the sol-gel method using spent lithium-ion batteries as raw matrial, and Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 cathode exhibited better charge/discharge behaviors and cycling stability than the pristine LiNi1/3Co1/3-xCrxMn1/3O2. At 0.2 C, the first discharge capacities of Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 and pristine LiNi1/3Co1/3-xCrxMn1/3O2 were 156.8 mAh g(-1) and 136.6 mAh g(-1 )with Coulomb efficiencies of 91% and 93%, respectively. The discharge capacities of Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 were 156.8, 151.5, and 145.3 mAh g(-1), after 30 cycles at 0.2, 0.5, and 1.0 C, which were 91.5%, 90%, and 88% of their initial discharge capacities, respectively. The superior capacity and cycling performance indicate that the structure of Cr-modified LiNi1/3Co1/3-xCrxMn1/3O2 is very stable, and the results reveal that Cr ion doping effectively suppressed the degree of mixing of Li+/Ni2+ so that a limited amount of Li+ was blocked by Ni2+.