The Effect of Titania Additives on the Performance of PEO-Based Solid Sodium Batteries: Bulk and Interfacial Aspects

Nanometric fillers are known to affect the electrochemical performance of polymer electrolytes. Here, nanowires and nanotubes of TiO₂ with the same crystal structure are compared as additives to poly(ethylene oxide) based electrolytes for solid state sodium batteries. Electrochemical studies of symmetric cells with blocking and non-blocking electrodes examined the effects of the additive shapes on the bulk electrolyte and Na-electrolyte interface. Impedance spectroscopy was used as a major electroanalytical tool. To obtain a full perspective, all-solid-state batteries were evaluated. In galvanostatic measurements the filler shape effect is most noticeable at a high current density. TiO₂ nanotubes improve the solid electrolyte behavior considerably more than titania nanowires. This effect is related mainly to the interface of the polymeric matrix with the electrodes.