Controllable defect engineering enhanced bond strength for stable electrochemical energy storage

Transition metal dichalcogenides (TMDs) with layered structure are regarded as a potential electrode material for high-performance energy storage devices, while intrinsic low electrical conductivity causes poor electrochemical performance. As we know, the change of atomic structure for TMDs can lead to the improvement of electrochemical properties. In this work, defect chemistry is employed to achieve this purpose. TiS2 as a typical electrode material is chosen to complete the study of controllable defect engineering. Theoretical calculations and experimental analysis confirm that concentration and species of defects can be controlled via adjusting the experimental conditions. A series of concentrations of sulfur vacancies are introduced in TiS2 by annealing methods. The introduction of sulfur vacancies enhances bond strength of Ti-S bonds near the defect area and improves electronic structure. Benefiting from the positive effect of sulfur vacancies, the electrochemical characteristics of TiS2 are greatly optimized, including cycle ability and dynamic characteristics. In addition, it is found that the improvement of electrochemical performance is closely related to the concentration of defects. These results reveal that controllable defect engineering may be a fascinating strategy to promote the advancement of TMDs in energy storage application.

Automated summary

This study employs defect chemistry to control the defect engineering of TiS2 materials, introducing sulfur vacancies to improve their electrochemical performance, including cycling ability and dynamic characteristics. The concentration and species of defects can be controlled by adjusting experimental conditions, and the enhancement of electrochemical performance is closely related to the concentration of defects.