Oxide-Coated Titanium Dioxide Nanotube Anodes in Sodium-Ion Batteries

Although lithium-ion batteries are commonly used for energy storage, the cost and availability of source materials have accelerated research in alternative sodium-ion batteries (NIBs). However, the energy storage capacity and cycle life of NIBs must be increased before becoming commercially viable. One approach to improving NIB performance is to stabilize the solid electrolyte interphase (SEI). The SEI develops when the electrolyte and electrodes react, forming an additional layer through which ions must diffuse. An unstable SEI layer can cause irreversible capacity loss, but an artificial SEI layer may lower capacity loss and increase stability over many cycles. Coating the anode surface with thin layers of different materials has been shown to stabilize the SEI. This work studies the effect of coating anatase and amorphous titanium dioxide nanotube anodes with thin films of aluminum oxide and additional titanium dioxide via atomic layer deposition (ALD). The capacity, cycle life, and role of surface energy will be investigated as a function of the thickness of these oxide coatings.