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

Musa Ali Cambaz, Bhaghavathi P. Vinayan, Holger Euchner, Rune E. Johnsen, Alexander A. Guda, Andrey Mazilkin, Yury V. Rusalev, Alexander L. Trigub, Axel Gross, Maximilian Fichtner
2018
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 Fm-3m LiNi0.5M0.5O2 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 +3 O2 with metals
more » ... O2 with metals active for +3/+4 redox couples are extended to ternary oxides with LiA0.5B0.5O2 with A=Ni +2 and B=Ti +4 , Zr +4 and V +4 in order to assess the impact of the different transition metal in the isostructural oxides. The direct synthesis of various new unknown ternary nickel based Fm-3m cation-disordered rock-salt positive electrode materials is presented with a particular focus on the LiNi0.5V0.5O2 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 -1 corresponding to 0.94 Li. For appropriate cut-off voltages, a long cycle life is achieved. The charge compensation mechanism is probed by XANES, confirming the reversible oxidation and reduction of V 4+ /V 5+ . The enhancement in the electrochemical performances within the presented compounds stresses the importance of mixed cationdisordered transition metal oxides with different electronic configuration.
doi:10.5445/ir/1000085224 fatcat:hbwrbwwdwzev5n4n5rbyge3aue