Regulating Polysulfide Transformation and Deposition Kinetics in Lithium–Sulfur Batteries Based on 3D Conductive Framework

• Published in: ACS applied materials & interfaces 2023-07, Vol.15 (28), p.33525-33540
• Main Authors: Liu, Lin, Meng, Yan, Ge, Yunchen, Xiao, Dan
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c03801

The polysulfide shuttle effect and slow liquid–solid conversion are supposed to be the main bottlenecks limiting lithium–sulfur battery practicality. Although a great deal of research has been devoted to the nucleation and transformation kinetics of polysulfides, many implicit details cannot be captured. In this work, we design a conducting network, FeN x -NPC, derived from hemin, and induce a 3D nucleation mode. Different from the control group with the 2D nucleation mode, a higher Li2S deposition and earlier nucleation are observed. Here, in situ impedance is applied to further understand the potential relationship between nucleation mode and liquid–solid transformation, and DRT results from impedance data are systematically compared from two aspects: (1) single battery under different voltages and (2) different batteries under the same voltage. It reveals that the 3D nucleation mode ensures more growth sites, on which a covered thin Li2S layer exhibits no charge transfer limitation. What is more, the porous structure with in situ-derived nanotubes favors Li+ faster diffusion. Hence, these advantages allow Li–S cells to deliver high capacity (about 1423 mA h g–1 at 0.1 C), low capacity attenuation (0.029% per cycle at 2 C), and excellent rate performance (620 mA h g–1 at 5 C).