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Electrochemical Analysis of Conductive Polymer‐Coated LiFePO 4 Nanocrystalline Cathodes with Controlled Morphology
Author(s) -
Dinh HungCuong,
Mho Sunil,
Yeo InHyeong
Publication year - 2011
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201100222
Subject(s) - nanocrystalline material , materials science , pedot:pss , electrochemistry , cathode , chemical engineering , conductive polymer , nanoparticle , coating , microstructure , polymer , electrical conductor , composite material , nanotechnology , electrode , chemistry , engineering
Abstract Nanocrystalline LiFePO 4 particles and donut‐ and dumbbell‐shaped LiFePO 4 microstructures hierarchically constructed with the nanoparticles were synthesized. Coating the surfaces of the LiFePO 4 particles with conductive polymers, poly‐3,4‐ethylenedioxythiophene (PEDOT), improved battery characteristics, such as specific capacity, capacity retention, and impedances, by increasing the ionic and electric conductivities of the cathode materials as well as by enhancing the accessibility of lithium ions. The nanocrystalline LiFePO 4 that was coated with PEDOT exhibited even larger values than the theoretical value of LiFePO 4 at a rate of 1 C or lower rates were observed, with its largest specific capacities of 190 mAh g −1 and 175 mAh g −1 at the rates of 0.2 C and 1 C, respectively, due to the compatibility of the redox characteristics of LiFePO 4 and PEDOT. The cathode composed of nanocrystalline LiFePO 4 that was coated with PEDOT exhibited the lowest value of the charge transfer resistances ( R ct ) from the electrochemical impedance analysis.