Carbon coated lithium cobalt phosphate for Li-ion batteries: Comparison of three coating techniques

• Published in: Journal of power sources Vol. 221; pp. 35 - 41
• Main Authors: Ni, Jiangfeng, Gao, Lijun, Lu, Li
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: Applied sciences; Carbon; Carbon coating; Carbon-carbon composites; Coating; Coating effects; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical behavior; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Exact sciences and technology; Lithium; Lithium cobalt phosphate; Lithium ion battery; Materials; Particulate composites; Scanning electron microscopy; Lithium ion battery; Lithium cobalt phosphate; Carbon coating; Electrochemical behavior; Performance evaluation; Alkaline storage battery; Coatings; Cobalt; Composite material; Electrochemical characteristic; Vapor deposition; Scanning electron microscopy; Pyrolysis; Electrochemical activity; Secondary cell; Carbon; X ray diffraction; Reversible capacity; Coated material; Lithium battery; Transmission electron microscopy; Lithium phosphate; Comparative study; Propane; Electrochemical impedance spectroscopy
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.07.107

Three techniques, i.e., pyrolysis of sucrose, spray of acetylene black, and propane vapor deposition, are adopted to coat carbon onto the surface of LiCoPO4 particles, and their effects are compared. The LiCoPO4/C composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). The results show that the coating techniques determine the property of carbon films formed on the surface of LiCoPO4 particles, which further affect the performance of LiCoPO4. A complete and homogeneous carbon layer is the key to a high electrochemical activity and stable cycle performance. Among these LiCoPO4/C composites, the material processed via the deposition technique shows a more uniform carbon layer than that of the others, thus it exhibits a large reversible capacity of 130 mA h g−1 with favorable cyclability and rate capability in the voltage range of 3.0–5.0 V. ► Three techniques are adopted to coat carbon on LiCoPO4 materials. ► The LiCoPO4/C processed via deposition shows a homogeneous carbon coating. ► LCP-deposition delivers a high capacity of 130 mA h g−1 with favorable cyclability. ► A uniform carbon layer is the key to a high and stable electrochemical performance.