Kinetic investigation of sulfurized polyacrylonitrile cathode material by electrochemical impedance spectroscopy

• Published in: Electrochimica acta Vol. 56; no. 14; pp. 5252 - 5256
• Main Authors: Wang, Li, Zhao, Jishi, He, Xiangming, Wan, Chunrong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 30.05.2011; Elsevier
• Subjects: Applied sciences; Cathodes; Charge transfer; Direct energy conversion and energy accumulation; Discharge; EIS; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical characteristics; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Electrolytes; Exact sciences and technology; Impedance; Lithium-ion batteries; Polyacrylonitriles; Sulfur; Sulfur composite cathode; Lithium-ion batteries; Electrochemical characteristics; EIS; Sulfur composite cathode; Cathode; Secondary cell; Electrode material; Discharge charge cycle; Acrylonitrile polymer; Composite electrode; Lithion ion batteries; Kinetics; Sulfur; Electrical characteristic; Modified material; Electrochemical impedance spectroscopy
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2011.03.009

► The impact of initial lithiation depth on the performance of sulfur composite materials is crucial. ► This research reveals more characteristics of the sulfur composite, which helps to understand more about the sulfur composite prepared by sulfurized polyacrylonitrile at 300°C. ► The sulfur composite material needs full lithiation at the initial cycle for activation to release its electrochemical property. To understand more about the sulfur composite prepared by sulfurized polyacrylonitrile at 300°C, electrochemical impedance spectroscopy (EIS) is employed to investigate the electrochemical properties of the sulfur composite cathode during discharge process. The impact of discharge depth on the performance of sulfur composite materials is investigated. The electrolyte solution resistance, the charge transfer resistance and the interface impedance are evaluated from the EIS analysis. The charge transfer resistance and the interface impedance increase during delithiation and decrease during lithiation, while the concentration of Li+ in the composite decreases and increases, respectively. Meanwhile the electrolyte solution resistance is likely to keep stable. The interface resistance and charge transfer resistance of the sulfur composite cathode decrease rapidly after initial lithiation, while Li+ diffusion coefficient and exchange current density increase rapidly. After the initial lithiation, they are likely to keep stable. This study reveals more characteristics of the sulfur composite, which is considered to be a promising candidate for large capacity cathode material.