Three-dimensional Ti3C2 structure design and in-situ growth of nano-TiO2 crystals to realize high performance lithium-sulfur battery

Lithium–sulfur (Li–S) batteries represent a promising energy storage system with the potential to replace traditional lithium-ion batteries. Recent research has explored the practical applications of Li–S batteries. However, due to the insulation properties of the sulfur components and the shuttle effect of polysulfides, the practical application of Li–S batteries is hindered by poor cycle stability and short life. In this study, we developed a controllable three-dimensional Ti3C2 structure design process, and through in situ growth of TiO2 nanocrystals, we prepared three-dimensional porous materials with TiO2@Ti3C2 heterostructures. These materials constructed using two-dimensional lamellar Ti3C2 function as a conductive skeleton to improve the conductivity of the sulfur cathodes, and through the in-situ growth of nano-TiO2 to introduce more binding sites and provide more chemisorption sites to limit the dissolution and shuttle of polysulfides. In addition, the TiO2@Ti3C2 heterointerface generated in situ on the surface of the lamellar structure can induce an internal electric field and increase active reaction sites, which promotes reaction kinetics, accelerates charge diffusion/transport, and promotes LiPS transformation. The materials designed in this study can effectively restrain the shuttle effect by realising the association process of adsorption, capture, and transformation of polysulfides. Thus, when applied as the sulfur cathode frame, it shows a high specific capacity of 1261.41 mAh g−1 at a rate of 0.1 C. In addition, a specific capacity of 66.5 % is maintained over 500 cycles at a rate of 1 C. This strategy supports the development of Li–S batteries with extraordinary performance and opens up a promising way to design next-generation electrochemical energy storage devices.