Titanium oxide-Ti3C2 hybrids as sulfur hosts in lithium-sulfur battery: Fast oxidation treatment and enhanced polysulfide adsorption ability

摘要

An ideal sulfur supporting material for lithium-sulfur battery should simultaneously incorporate the features of polysulfides adsorption/trapping and high conductivity, which are important for achieving good cycle performance and finally practical use. In this work, accordion-like titanium oxides-Ti3C2 MXene (Ti3C2Ox) hetero-structure was synthesized via a fast annealing treatment to Ti3C2 MXene (Ti3C2) in air. Oxidation temperature plays a key role on the formation of accordion-like Ti3C2Ox. The synthesized Ti3C2Ox material under 500 degrees C exhibits the most optimal structure, which presents the evenly distributed titanium oxides on the Ti3C2 nanosheets. This heterostructural material combines the high chemical adsorption ability of titanium oxides for LiPSs and good electronic conductivity of Ti3C2. After infiltrating with sulfur, a substantial specific capacity of 662 mAh g(-1) is achieved after 1000 cycles at 1 C (1.675 A g(-1)), corresponding to a very low capacity fading of 0.053% per cycle. Additionally, a reversible capacity of 367 mAh g(-1) is still obtained at a high rate of 10 C. The Ti3C2Ox synthesized by the facile oxidation treatment is a highly promising electrode material and contributes to accelerate the practical use of Li-S battery.