Enhanced Cyclability of Li–O₂ Batteries Based on TiO₂ Supported Cathodes with No Carbon or Binder

Abstract

The decomposition of carbon materials and organic binders in Li–air batteries has been reported repeatedly in recent literature. The decomposition of carbon can harm the batteries' cyclability further by catalyzing electrolyte degrading. Therefore, there is a critical need to exploit a new catalyst support substituting carbon and develop a binder free cathode preparation strategy for Li–air batteries. Herein, TiO2 nanotube arrays growing on Ti foam are used as the catalyst support to construct carbon and binder free oxygen diffusion electrodes. After being coated with Pt nanoparticles by a cool sputtering approach, the TiO2 nanotube arrays are used as cathodes of Li–O2 batteries. Benefiting from the stability of TiO2 in the discharge/charge processes, the Li–O2 batteries realize enhanced cyclability at high current densities (for instance, more than 140 cycles at 1 or 5 A g–1), within wide discharge/charge voltage windows (for instance, 1.5–4.5 V). X-ray photoelectron spectra and a scanning electron microscope image of the cathodes after cycling at 5 A g–1 150 times indicate that the TiO2 nanotubes can remain stable in the long term cycle test. 1H nuclear magnetic resonance analysis reveals that the tetraethylene glycol dimethyl ether electrolyte has no degradation, showing enhanced stability compared with that in the carbon containing batteries.