Architecture and Performance of the Novel Sulfur Host Material Based on Ti₂O₃ Microspheres for Lithium-Sulfur...

Lithium-sulfur batteries are considered as promising next-generation green secondary batteries. Irrespective of the enhancement of the cycling stability or the suppression of polysulfide species shuttle, although much progress has recently been achieved, improving the conductivity of host materials and capturing the sulfide species as far as possible are still hot topics in the research of lithium-sulfur batteries nowadays. Here, we put forward a novel sulfur host architecture based on Ti₂O₃ microspheres fabricated by magnesiothermic reduction. The Ti₂O₃ microspheres possess both high electronic conductivity and excellent ability of anchoring lithium polysulfide species. The high electronic conductivity endowed by a narrow band gap can adequately activate insulative sulfur and reduce the battery resistance so that high specific capacity and excellent rate capability can be achieved, while the polar Ti₂O₃ could afford abundant polar active sites for the absorption of polysulfides for high capacity retention. As a result, Ti₂O₃ microspheres are applied in the research of lithium-sulfur batteries; excellent electrochemical performance has been revealed. The initial specific capacity is 1245 mAh g^-1 at 0.2C, with 91.57% capacity retention after 180 cycles. Even with a high areal loading of 3.6 mg cm^-2, an initial capacity of 665 mAh g^-1 at 0.5C and a good capacity retention of 70.98% after 300 cycles could be achieved. Apparently, the preparation and application of Ti₂O₃ microspheres can not only further extend the application field of the Ti-based compound but also boost the electrochemical performance of lithium-sulfur batteries.