On the electroanalytical characterization of Li_xCoO₂, Li_xNiO₂ and LiMn₂O₄ (spinel) electrodes in repeated lithium intercalation-deintercalation processes

This paper reports on electroanalytical studies of the intercalation-deintercalation of lithium into lithiated transition metal oxides which are used as cathodes for Li ion batteries. These include Li_xCoO₂ Li_xNiO₂ and Li_xMn₂O₄ spinel. The basic electroanalytical response of these systems in LiAsF₆ 1M/EC-DMC solutions was obtained from the simultaneous use of slow and fast scan cyclic voltammetry (SSCV), potentiostatic intermittent titration (PITT) (from which D vs. E was calculated), and impedance spectroscopy (ELS). Surface sensitive FTIR spectroscopy and XRD were also used for surface and 3D characterization, respectively. A large and important denominator was found in the electrochemical behavior of lithium intercalation-deintercalation into these transition metal oxides and graphite. The use of the electroanalytical response of these systems as a tool for the study of stabilization and failure mechanisms of these materials as cathodes in rechargeable Li batteries is demonstrated and discussed.