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 / LiFePO₄ is a type of cathode material in ion lithium batteries that is very well known for its environmental friendliness and low prices. LiFePO₄/C powder can be obtained from the solid state method. In this study the variables used were the types of precursors : iron sulfate (FeSO₄), iron oxalate (FeC₂O₄) and FeSO₄+charcoal. Synthesis of LiFePO₄/C powder using Li:Fe:P at 1:1:1 %mol. Based on the XRD results, LiFePO₄/C from FeSO₄+charcoal shows the LiFePO₄/C peaks according to the JCPDS Card with slight impurities when compared to other precursors. XRD results of LiFePO₄/C with precursors of FeSO₄ or FeC₂O₄ shows more impurities peaks. This LiFePO₄/C cathode is paired with lithium metal anode, activated by a separator, LiPF₆ as electrolyte. Then this arrangement is assembled become a coin cell battery. Based on the electrochemical results, Initial discharge capacity of LiFePO₄/C from the FeSO₄ precursor is 19.72 mAh/g, while LiFePO₄/C with the FeC₂O₄ precursor can obtain initial discharge capacity of 17.99 mAh/g, and LiFePO₄/C with FeSO₄+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>