Effect of composite electrode slurry preparation method on electrochemical characteristics of lifepo4/c based li-ion cell

Abstract

LiFePO4 is a potential cathode material for its application in Li-ion batteries to provide high energy density, high power density and flat discharge voltage which are the basic requirements of underwater electric vehicles. It is non toxic, low cost, safe and environmentally benign material with high operating voltage (*3.4 V vs. Li). Although it has a high specific theoretical capacity (170 mAh/g), its discharge capacity is highly influeced by the method of preparation and mixing sequence of the ingredients of composite slurry for coating of electrode. In the present work, the electrode slurry is prepared by two different methods namely conventional method and conductive glue method. CR2032 coin cells in half cell configuration are fabricated using the electrodes prepared by both these methods. Electrochemical characterization of these half cells is carried out using cyclic voltammetry, AC-impedance, charge-discharge characteristics and specific capacity studies. It is found that coin cells made of electrodes prepared by conductive glue method provided higher capacities and less fading of capacity with cycles. It is opined that the conductive glue method helps in forming the electronic conductive network with uniform distribution of carbon additive around the active material resulting in homogeneous mixing of electrode slurry and quality coating thereby improving cell capacity and lower fade outs of capacity.