Novel iron-cobalt derivatised lithium iron phosphate nanocomposite for lithium ion battery cathode

Abstract

Described herein is the electrochemical study conducted on lithium ion battery cathode material consisting of composite of lithium iron phosphate (LiFePO(sub4), iron-cobalt derivatised carbon nanotubes (FeCo-CNT) and polyaniline (PA) nanomaterials (LiFePO4/FeCoCNT-PA); and pristine LiFePO(sub4). The design of the nanocomposite electrode involves first, the attachment of FeCo nanoparticles unto the nanotubes matrix via in situ reductive precipitation of the metal precursors within a CNT suspension. Results from High Resolution Transmission Electron Microscopy show the successful attachment of FeCo nanoparticles to the CNTs. The composite cathode exhibits better reversibility and kinetics than the pristine LiFePO4 due to the presence of the conductive additives in the former. This is demonstrated in the values of the diffusion coefficient (D) and standard rate constant (ks) determined through cyclic voltammetry. For the composite cathode D = 1.0 x 10(sup-9) cm(sup2) s(sup-1) and k(subs) = 7.05 x 10(sup-7) cm s(sup-1) whereas the pristine electrode has values of 4.81 x 10(sup-11) cm(sup2) s(sup-1) and 2.68 x 10(sup-7) cm s(sup-1) for D and k(subs), respectively. Similar trend is observed in the results obtained from electrochemical impedance spectroscopy.