Synthesis and electrochemical properties of LiFePO4-graphite nanofiber composites as cathode materials for lithium ion batteries

• Published in: Journal of power sources Vol. 244; pp. 586 - 591
• Main Authors: Nguyen, Van Hiep, Jin, En Mei, Gu, Hal-Bon
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2013; Elsevier
• Subjects: Applied sciences; Charge; Conductivity; Current density; Direct energy conversion and energy accumulation; Discharge; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electron microscopy; Electronics; Exact sciences and technology; Graphite nanofibers-antler; Hydrothermal reaction; Insertion; Lithium; Lithium ion battery; Lithium iron phosphate; Lithium-ion batteries; Materials; Nanostructure; Lithium iron phosphate; Conductivity; Lithium ion battery; Graphite nanofibers-antler; Hydrothermal reaction; Lithium ion batteries; Nanofiber; Electrode material; Composite material; Graphite fiber; Composite electrode; Chemical synthesis; Modified material; Iron phosphate; Cathode; Iron Phosphates; Secondary cell; Electrochemical detector; Electrochemical properties; Quaternary compound; Hydrothermal synthesis; Conductometry; Lithium phosphate; Lithium Phosphates; Nanostructured materials
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.01.073

In this paper, the influences of graphite nanofiber-antler (GNF) adding on LiFePO4 are studied by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), charge/discharge tests, and Ac impedance spectroscopy. In the results, the XRD patterns index to a single-phase material having an orthorhombic olivine-type structure with a space group of Pnma. The 7% GNF-added LiFePO4 demonstrates a higher conductivity than the pure LiFePO4 samples. The electronic conductivity of 7% GNF-added LiFePO4 is 5.32 × 10−3 S cm−1. The CV curves show that the 7% GNF-added LiFePO4 has higher electrochemical reactivity for lithium insertion and extraction than the pure LiFePO4 with the current is 1.65 mA and the voltage between redox peaks is 0.25 V. A discharge capacity of 131.5 mAh g−1 is achieved at a current density of 0.1 mA cm−2 with a slight decline during cycling. ► LiFePO4-Graphite nanofiber(GNF) successfully prepared by the hydrothermal method. ► The increase in electronic conductivity, and discharge capacity are determined. ► The electronic conductivity of LiFePO4-GNF (7%) is 5.32 × 10−3 S cm.−1 ► LiFePO4-GNF (7%) shows the best electrochemical performances.