Thermal explosion synthesis of LiFePO 4 as a cathode material for lithium ion batteries
- PDF / 1,612,821 Bytes
- 13 Pages / 439.37 x 666.142 pts Page_size
- 94 Downloads / 242 Views
Thermal explosion synthesis of LiFePO4 as a cathode material for lithium ion batteries Xiujuan Chen1 Bingxue Sun2
•
Xi Peng2 • Penglin Zhang2
•
Received: 5 August 2016 / Accepted: 17 January 2017 Springer Science+Business Media Dordrecht 2017
Abstract Olivine-type LiFePO4 cathode material was successfully synthesized by a simple method of thermal explosion (TE) using hexamethylenetetramine (C6H12N4) as fuel. The crystalline phase, morphology and particle size of powders were characterized by X-ray diffraction, scanning electron microscope, particle size analyzer and transmission electron microscope measurements. And the electrochemical properties were investigated by galvanostatic charge–discharge tests and electrochemical impedance spectroscopy. The results indicated that the samples synthesized by TE showed an olivine crystal structure with space group Pnmb. In addition, both structure and particle size could be adjusted by the amount of C6H12N4 and the heat treatment temperature in the TE. When the amount of C6H12N4 was 30 wt%, the heat treatment temperature was 800 C and the particlesize distribution fell in a range of 300–400 nm. Electrochemical tests indicated that the LiFePO4 sample synthesized in such conditions, without additional carbon coating and cation doping, shows a discharge capacity of 110.4 mAh g-1 and an excellent capacity retention rate of 87% after 50 cycles at 1 C. Keywords Lithium ion batteries LiFePO4 TE Cathode materials
& Xiujuan Chen [email protected] 1
School of Mechanical and Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China
2
State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
123
X. Chen et al.
Introduction With the rapid development of global industrialization, the energy exhaustion in the world has become a serious problem which cannot be ignored by every country. Therefore, it has attracted much attention to develop sustainable and clean energy products. Polyanion materials such as LiFePO4 [1], LiCoPO4 [2] and Li2FeSiO4 [3] have been investigated as cathode materials for lithium ion batteries. Among these ployanion materials, LiFePO4 has drawn a vast amount of interest in terms of application, especially in the automotive industry due to its high theoretical capacity (170 mAh g-1), good thermal stability, flat voltage profile, long cycle life and environment benignity [4, 5]. However, poor conductivity and a slow lithium ion diffusion rate have become a bottleneck. Fortunately, this can be mitigated by carbon coating [6], cation doping [7] and particle size minimizing [8]. And many methods have been developed to synthesize LiFePO4, such as solid-state [9], hydrothermal [10], and sol–gel methods [11]. Unfortunately, there are many disadvantages in these methods, which limit much wider applications of LiFePO4, such as the high temperatures, long synthesis times and so on [12]. Compared with the aforementioned approaches, combustion synthesis (CS) has
Data Loading...
