Carbon Nanotube-Encapsulated Bi₂S₃ Nanorods as Electrodes for Lithium-Ion Batteries and Lithium–Sulfur Batteries

Abstract

Bi2S3 has attracted great interest in the field of energy storage due to its unique layer structure and high theoretical capacity. However, the large volume variation and side reaction greatly limit the application of Bi2S3. Hence, the Bi2S3 nanorod-encapsulated into carbon nanotubes (CNTs) were prepared by a facile method. In such a structure, the walls of the CNTs can be used as a physical barrier, which may segregate the Bi2S3 nanorods from the electrolyte to avoid the side reaction. Moreover, enough space in the structure can accommodate the volume variation during cycling to retain the integrity of the electrode and improve the cycling stability. Therefore, as the anode for lithium-ion batteries (LIBs), it shows a high capacity of 581 mA h g–1 after 600 cycles at 1 A g–1. Meanwhile, as the sulfur host, the conductivity of the cathode is largely enhanced due to the existence of a carbon matrix. Also, the diffusion of lithium polysulfides can be curbed under the synergy of the chemical adsorption of Bi2S3 nanorods and the physical retention of CNTs. Therefore, the CNTs@Bi2S3/S electrode also exhibits advanced performance in lithium–sulfur batteries (LSBs). This work provides an innovative idea for the application of Bi2S3 in both LIBs and LSBs.