Charge Transport and Ion Kinetics in 1D TiS2 Structures are Dependent on the Introduction of Selenium Extrinsic Atoms

Abstract

Improving charge insertion into intercalation hosts is essential for crucial energy and memory technologies. The layered material TiS₂ provides a promising template for study, but further development of this compound demands improvement to its ion kinetics. Here, we report the incorporation of Se atoms into TiS₂ nanobelts to address barriers related to sluggish ion motion in the material. TiS_1.8Se_0.2 nanobelts are synthesized through a solid-state method, and structural and electrochemical characterizations reveal that solid solutions based on TiS_1.8Se_0.2 nanobelts display increased interlayer spacing and electrical conductivity compared to pure TiS₂ nanobelts. Cyclic voltammetry and electrochemical impedance spectroscopy indicate that the capacitive behavior of the TiS₂ electrode is improved upon Se incorporation, particularly at low depths of discharge in the materials. The presence of Se in the structure can be directly related to an increased pseudocapacitive contribution to electrode behavior at a low Li⁺ content in the material and thus to improved ion kinetics in the TiS_1.8Se_0.2 nanobelts.