LiNi x Cu0.5 − x Mn1.5 O 4 Spinel Electrodes, Superior High‐Potential Cathode Materials for Li Batteries: I. Electrochemical and Structural Studies

(0 ≤ x ≤0.5) spinel materials that are of interest as electrodes for lithium‐ion batteries have been studied by crystallographic and electrochemical methods. Electrochemical results show that the inclusion of Ni into the Cu‐modified spinel increases the overall reversible capacity from 72 mAh/g with at 4.95 V to 120 mAh/g with at 4.6 V. The Cu‐rich spinels in the system show enhanced stability upon cycling. These spinel products are difficult to prepare in single‐phase form. Neutron diffraction data show that the end members and contain small amounts of lithium‐nickel‐oxide and lithium‐copper‐oxide impurity phases, respectively; these impurities affect the composition of the spinel component. The composition of the spinel component in was determined from a combined X‐ray and neutron diffraction profile refinement to be .