Exploring the electrochemical performance of layered Bi2Se3 hexagonal platelets as the anode material for lithium-ion batteries

Abstract

The escalating need for lithium-ion batteries (LIBs), driven by their expanding range of applications in our daily lives, has led to a surge in interest in metal selenides as potential anode materials. Among them, Bi₂Se₃ stands out as a promising anode material for LIBs due to its unique layered structure. Herein, we explored hexagonally structured layered Bi₂Se₃ platelets synthesized using the solvothermal method. The electrochemical performance of these platelets in LIBs was thoroughly examined, revealing an impressive initial discharge specific capacity of 556 mA h g⁻¹ at a current density of 100 mA g⁻¹ and a coulombic efficiency of 66.5%. Improved cycling stability, rate performance, and discharge voltage profile at various current densities were observed. The plateaus observed during the charge/discharge profile were clearly illustrated by the CV results. The reaction kinetics indicated that both ion diffusion and pseudo-capacitance behavior are crucial for the observed high electrochemical performance. Moreover, the hexagonal Bi₂Se₃ platelets exhibited a high ion-diffusion coefficient of 1.8 × 10⁻¹³ cm² s⁻¹ and a charge transfer impedance of 23 Ω post-cycling. Furthermore, the crystal structure, lattice vibrational bonding, and surface morphology of Bi₂Se₃ were explored using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. FTIR spectroscopy was utilized for identifying the functional groups, while X-ray photoelectron spectroscopy (XPS) was used to identify the elemental composition and oxidation states of Bi₂Se₃.