Understanding Electrode-Electrolyte Solution Interactions Between TiO2 Nanotube Electrode and Nonaqueous Electrolytes for Sodium-Ion Batteries

Abstract

Sodium-ion battery technology presents a promising sustainable alternative to the current dominating lithium-ion battery technology due to its low cost associated with its high earth abundance. It has been shown that the interfacial chemistry between anodes and sodium-based or lithium-based electrolytes have markedly different effect even when using the same solvent. It is important to investigate sodium-based electrolytes and to elucidate the mechanisms of electrode and electrolyte interactions. The design and development of next generation electrolytes for sodium-ion batteries is catered towards the improved performance based on evaluation of thermodynamic /transport properties, chemical and electrochemical stability, thermal stability and interfacial chemistry. In this work, we have investigated the electrochemical properties of TiO2 nanotube electrode in various electrolytes containing different solvent mixtures (cyclic, acyclic carbonates) with NaClO4 1 salt and NaPF6 salt and have found that the interaction between the TiO2NT electrode and the nonaqueous electrolytes plays a critical role in the charging/discharging processes. In addition, we have conducted fundamental studies of the chosen sodium-based electrolytes on their chemical stability, thermal stability and electrochemical stability.