All-Electrochem-Active Thick Electrode with Dual-Continuous TiO₂-Carbon Integrated Skeletons for Low-Temperature Lithium Storage

Newly designed all-electrochem-active thick electrode (∼500 μm) with dual-continuous integrated skeletons of defective rutile-anatase TiO2 (D-R-A-TiO2) heterojunctions and carbon have been introduced to enhance efficient electron–ion transport for high-rate energy storage, which provides a new idea for low-temperature lithium storage. For the first time, we anneal anatase TiO2 integrated carbon under CO2 atmosphere for converting anatase to rutile and activating carbon simultaneously, to fabricate freestanding all-electrochem-active thick electrode. The D-R-A-TiO2 heterojunctions contain a type II staggered band alignment, which significantly induce highly localized electrons and lower the migration barrier of ions. The continuous D-R-A-TiO2 heterojunctions form synergistically advantageous electronic networks, and the thick electrode (up to 60.97 mg cm–2) delivers outstanding areal capacity (14.14 mAh cm–2 at 0.61 mA cm–2) under 30 °C. The areal capacity is 8.62 mAh cm–2 at 0.57 mA cm–2 under −10 °C. When the temperature drops to −20 °C, the areal capacity still delivers 4.92 mAh cm–2 at 0.57 mA cm–2. And the D-R-A-TiO2 electrode still delivers 3.2 mAh cm–2 capacity after 70 cycles at 0.57 mA cm–2 under −20 °C.