Pyrolysis of activated carbon from coconut shell and its characteristic in the LiFePO4/V/C composite for lithium ion battery cathode

Most of the time, coconut shells from the coconut farms have not been used but for charcoal purpose. In this work, the charcoal from the coconut shells was converted into an activated carbon and used it for the development of lithium ion battery. The development was begun by firstly synthesizing LiFePO4 (LFP) through a hydrothermal route using stoichiometric amounts of precursors LiOH, NH4H2PO4, and FeSO4.7H2O. The as-synthesized LFP was then mixed with variation of vanadium concentrations and a fix concentration of the carbon pyrolyzed from the coconut shells. X-ray diffraction (XRD) was used to characterize the crystal structure, whereas a scanning electron microscope (SEM) was used to characterize surface morphology of the composite. The characteristic of the composite was further examined an electrochemical impedance spectroscopy (EIS) for the conductivity. The XRD results showed that the LiFePO4/V/C has been formed successfully with an olivine structure. The SEM results depicted an agglomerate morphology but most of LiFePO4/V particles have been coated by the carbon. The EIS results showed conductivity values of 1.3387×10-2 S/cm, 1.184×10-3 S/cm, 1.7241×10-3 S/cm, and 6.6423×10-4 S/cm for the LFP/C-0V, LFP/C-3V, LFP/C-5V, and LFP/C-7V samples, respectively. The performance test indicated that coconut shell has a great potential as a cheap carbon resource for the development of lithium ion battery cathode.