Superior Capacity Retention Spinel Oxyfluoride Cathodes for Lithium-Ion Batteries

Spinel ( , Ni, and Cu) oxyfluoride cathodes have been synthesized by firing the cation-substituted oxides with at a moderate temperature of . With this low-temperature approach, fluorine contents up to could be incorporated into the spinel lattice. The oxyfluoride compositions such as exhibit excellent capacity retention at with capacities over and good rate capability. The superior electrochemical performance is found to be due to a smaller lattice parameter difference between the two cubic phases formed during the charge-discharge process and the consequent suppressed manganese dissolution.