TiO₂-based cathode with modest oxygen vacancies and defective Ti³⁺ for long-life lithium-oxygen batteries

Rational designed cathode including the surface engineering of catalyst e.g. defect creation and the precise selection of catalyst that could avoid the side reaction of carbon have been verified of great concern in achieving long-life lithium-oxygen batteries. Herein, oxygen vacancies and Ti³⁺ were both introduced into a tubular brush-like cathode structure, in which nano-needled TiO₂ grew in situ on carbon textile (CT), and further enhancement of the catalytic performance was achieved by loading RuO₂. The introduction of oxygen vacancies and Ti³⁺ in TiO₂ could regulate the charge overpotential, and the synergistic effect between ruthenium dioxide and titanium dioxide accelerated charge transfer, and adjusted the electronic structure to achieve the surface-mediated formation mechanism of thin film lithium peroxide. Besides, TiO₂ grew evenly on the surface of carbon matrix, thus restraining the carbon corrosion. Thus, CT@TiO₂ and CT@TiO₂-RuO₂ provided low overpotentials of 0.94 V and 0.69 V and superior cycle life. Meanwhile, an ultra-long life of 317 cycles was achieved in the battery with the CT@TiO₂-RuO₂ cathode at a high current density of 0.3 mA cm⁻².