Enhanced cyclability of Li-O₂ batteries based on TiO₂ supported cathodes with no carbon or binder

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.