Li 4/3 Ni 1/3 Mo 1/3 O 2 – LiNi 1/2 Mn 1/2 O 2 Binary System as High Capacity Positive Electrode Materials for Rechargeable Lithium Batteries

Abstract

© The Author(s) 2018. A binary system of x Li 4/3 Ni 1/3 Mo 1/3 O 2 – (1–x) LiNi 1/2 Mn 1/2 O 2 is studied as high-capacity positive electrode materials for rechargeable lithium batteries. Structural and electrochemical properties of oxides with different compositions in this binary system are examined. Mo ordering is retained for 1 ≤ x ≤ 1/3 with a monoclinic symmetry and disappears for x ≤ 1/6 with a rhombohedral symmetry. Compared with Li 4/3 Ni 1/3 Mo 1/3 O 2 , partial substitution of Mn for Mo lead to the improvement of reversible capacity and reduction of polarization. For Li 6/5 Ni 2/5 Mn 1/5 Mo 1/5 O 2 (x = 1/3) and Li 9/8 Ni 7/16 Mn 5/16 Mo 1/8 O 2 (x = 1/6), high reversible capacities of around 200 mAh g −1 are obtained. Improved cycling performance is achieved through the optimization of voltage ranges. Further structural characterization by ex–situ XRD reveals that the improved reversibility for the Mn-substituted samples mainly results from the suppression of Mo migration during cycling, probably associated with partial oxygen loss.