Transmission Electron Forward Scattered Diffraction and Low Voltage SEM/STEM Characterization of Binder-Free TiO2 Electrodes

Abstract

Graphite, the current commercial anode material in batteries suffers from the formation of a surface/electrolyte interface (SEI) layer that adversely affects performance. However, titania (TiO2) does not form an SEI layer and is both abundant and inexpensive, making it a prime anode material replacement [1]. While much work has been done to determine the effects of morphology and phase of TiO2 on lithium intercalation, the effect of the method fabrication of the electrode on its electrochemical performance is still unknown. Currently, electrodes are fabricated using active material, conductive additives, and a non-electroactive polymer binder mixed mechanically with a solvent. In this work, we introduced a chemo-mechanical fabrication method that produces binder-free electrodes. Without binder, more loading of active material is possible. Further, agglomeration of both TiO2 and conductive additives that occurs with the binder-based method is limited by using dispersants. Finally, the electrode is sintered, forming a 3-dimensional mesoporous structure that provided a 25% increase in capacity over the binder-based method, as well as better capacity retention over multiple cycles.