Design of Nickel-Based Cation-Disordered Rock-Salt Oxides: The Effect of Transition Metal (M = V, Ti, Zr) Substitution in LiNi 0.5 M 0.5 O 2 Binary Systems

Cation-disordered oxides have been ignored as positive electrode material for a long time due to structurally limited lithium insertion/extraction capabilities. In this work, a case study is carried out on nickel-based cation-disordered Fm3 ̅m LiNi M O positive electrode materials. The present investigation targets tailoring the electrochemical properties for nickel-based cation-disordered rock-salt by electronic considerations. The compositional space for binary LiM O with metals active for +3/+4 redox couples is extended to ternary oxides with LiA B O with A = Ni and B = Ti , Zr , and V to assess the impact of the different transition metals in the isostructural oxides. The direct synthesis of various new unknown ternary nickel-based Fm3̅ m cation-disordered rock-salt positive electrode materials is presented with a particular focus on the LiNi V O system. This positive electrode material for Li-ion batteries displays an average voltage of ∼2.55 V and a high discharge capacity of 264 mAhg corresponding to 0.94 Li. For appropriate cutoff voltages, a long cycle life is achieved. The charge compensation mechanism is probed by XANES, confirming the reversible oxidation and reduction of V /V . The enhancement in the electrochemical performances within the presented compounds stresses the importance of mixed cation-disordered transition metal oxides with different electronic configuration.