Synthesis of LiFePO 4 in an Open-air Environment
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Synthesis of LiFePO4 in an Open-air Environment 1,2,4
Fei Gu , Kichang Jung3,4,Taehoon Lim1,2,4, Alfredo A. Martinez-Morales1,2,4 1 Materials Science and Engineering Program, University of California, Riverside, California 92521 2 Winston Chung Global Energy Center, University of California, Riverside, California 92521 3 Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521 4 College of Engineering Center for Environmental Research and Technology University of California, Riverside, California 92507 ABSTRACT Among different efforts to increase the competitiveness of lithium-ion batteries (LIBs) in the energy storage marketplace, reducing the cost of production is a major effort by the LIB industry. This work proposes a synthesis method to decrease the production cost for LiFePO4, by synthesizing the material through an open-air environment solid state reaction. The lithium (Li)-ion battery is a member of the family of rechargeable batteries. In our approach, iron phosphate (FePO4) powder is preheated to eliminate moisture. Once dried, the FePO4 is mixed with lithium acetate (CH3COOLi), and the mixture is heated in a tube furnace. The solid-state reaction is conducted in an open-air environment. In order to minimize the oxidation of the formed LiFePO4, a modified tube reaction vessel is utilized during synthesis. Xray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) are used to characterize the crystal structure and chemical composition of the synthesized material. Furthermore, scanning electron microscopy (SEM) characterization shows the grain size of the formed LiFePO4 to be in the range of 200 nm to 600 nm. Cycling testing of fabricated battery cells using the synthesized LiFePO4 is done using an Arbin Tester. INTRODUCTION Rechargeable batteries. Its name is based on the fact that lithium ions move to the anode during discharge, and back to the cathode during charging. Lithium-ion batteries are widely used in applications ranging from personal electronics to large scale power systems. Li-ion batteries are suitable for portable devices because of their high-energy density, cost-competitiveness, and long cycle ability [1]. The typical structure of a half Li-ion coin cell consists of a lithium anode, a membrane, an electrolyte, and a cathode. A spacer, a spring, and a bottom case are connected with the anode. The coin cell is enclosed with a top case, and compressed. During discharge of the Li-ion battery the anode accepts lithium ions, and during charge the cathode intercalates the Li-ions. A complete charge followed by a discharge is referred to as a “cycle” [2]. LiFePO4 has great potential in commercial applications for many reasons. Iron is abundant in nature [3], which makes LiFePO4 cost competitive. It also has excellent thermal stability and cycle life [4]. Moreover, it has lower toxicity than traditional cathode materials such as LiCoO2 and LiMn2O4 [5]. LiFePO4 cell has a midpoint discharge potential of 3.45 V [6]. This value is relatively low w
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