Influence Comparison of Precursors on LiFePO4/C Cathode Structure for Lithium Ion Batteries

Abstract

<p>Electricity is the most energy demanded in this era. Energy storage devices must be able to store long-term and portable. A lithium ion battery is a type of battery that has been occupied in a secondary battery market. Lithium iron phosphate / LiFePO<sub>4</sub> is a type of cathode material in ion lithium batteries that is very well known for its environmental friendliness and low prices. LiFePO<sub>4</sub>/C powder can be obtained from the solid state method. In this study the variables used were the types of precursors : iron sulfate (FeSO<sub>4</sub>), iron oxalate (FeC<sub>2</sub>O<sub>4</sub>) and FeSO<sub>4</sub>+charcoal. Synthesis of LiFePO<sub>4</sub>/C powder using Li:Fe:P at 1:1:1 %mol. Based on the XRD results, LiFePO<sub>4</sub>/C from FeSO<sub>4</sub>+charcoal shows the LiFePO<sub>4</sub>/C peaks according to the JCPDS Card with slight impurities when compared to other precursors. XRD results of LiFePO<sub>4</sub>/C with precursors of FeSO<sub>4</sub> or FeC<sub>2</sub>O<sub>4</sub> shows more impurities peaks. This LiFePO<sub>4</sub>/C cathode is paired with lithium metal anode, activated by a separator, LiPF<sub>6</sub> as electrolyte. Then this arrangement is assembled become a coin cell battery. Based on the electrochemical results, Initial discharge capacity of LiFePO<sub>4</sub>/C from the FeSO<sub>4</sub> precursor is 19.72 mAh/g, while LiFePO<sub>4</sub>/C with the FeC<sub>2</sub>O<sub>4</sub> precursor can obtain initial discharge capacity of 17.99 mAh/g, and LiFePO<sub>4</sub>/C with FeSO<sub>4</sub>+charcoal exhibit initial discharge capacity of 21.36 mAh/g. This means that the presence of charcoal helps glucose and nitrogen gas as reducing agents.</p>