Breathable Carbon‐Free Electrode: Black TiO₂ with Hierarchically Ordered Porous Structure for Stable Li–O₂ Battery

Abstract

This paper introduces oxygen‐deficient black TiO2 with hierarchically ordered porous structure fabricated by a simple hydrogen reduction as a carbon‐ and binder‐free cathode, demonstrating superior energy density and stability. With the high electrical conductivity derived from oxygen vacancies or Ti3+ ions, this unique electrode features micrometer‐sized voids with mesoporous walls for the effective accommodation of Li2O2 toroid and for the rapid transport of reaction molecules without the electrode being clogged. In the highly ordered architecture, toroidal Li2O2 particles are guided to form with a regular size and separation, which induces the most of Li2O2 external surface to be directly exposed to the electrolyte. Therefore, large Li2O2 toroids (≈300 nm) grown from solution can be effectively charged by incorporating a soluble catalyst, resulting in a very small polarization (≈0.37 V). Furthermore, disordered nanoshell in black TiO2 is suggested to protect the oxygen‐deficient crystalline core, by which oxidation of Ti3+ is kinetically impeded during battery operation, leading to the enhanced electrode stability even in a highly oxidizing environment under high voltage (≈4 V).

Oxygen‐Deficient Blue TiO2 for Ultrastable and Fast Lithium Storage

“…The presence of oxygen vacancies in B‐TiO 2− δ was validated by Raman spectroscopic studies ( Figure 3 a). Compared to the relatively sharp E g and A 1g peaks in W‐TiO 2 , the significant peak broadening and red‐shift in B‐TiO 2− δ can be related to oxygen vacancies (Figure S4 and Table S1, Supporting Information) . In addition, electron paramagnetic resonance (EPR) spectrometry was also employed to further confirm the existence of oxygen vacancies .…”

Porous Titanium Oxide Microspheres as Promising Catalyst for Lithium–Oxygen Batteries

“…Ti‐based transition metal oxides are potential catalysts for Li–O 2 battery . In this experiment, TiO 2 mesoporous microspheres were used as positive electrode, and Li–O 2 battery was assembled to measure the differential electrochemical mass spectrometry (DEMS).…”

Advances in Flexible and Wearable Energy‐Storage Textiles

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