Ionic and Electronic Conductivities of Atomic Layer Deposition Thin Film Coated Lithium Ion Battery Cathode ParticlesRSC Advances
AbstractIt is imperative to ascertain the ionic and electronic components of the total conductivity of an electrochemically active material. A blocking technique, called the “Hebb-Wagner method”, is normally used to explain the two components (ionic and electronic) of a mixed conductor, in combination with the complex ac impedance method and dc polarization measurements. CeO2 atomic layer deposition (ALD)-coated and uncoated, LiMn2O4 (LMO) and LiMn1.5Ni0.5O4 (LMNO) powders were pressed into pellets and then painted with silver to act as a blocking electrode. The electronic conductivities were derived from the currents obtained using the dc chronoamperometry mode. The ionic conductivities were calculated based on results of the electronic conductivities and the mixed conductivities obtained using the ac impedance method. The results showed that the ionic conductivities of the LMO and LMNO particles coated with CeO2 thin films were twice as much as those of the uncoated LMO and LMNO particles. Also, LMO particles coated with insulating materials, such as alumina and zirconia ALD films, were tested and compared. No significant effects of the substrates on the ionic conductivities of the coated and uncoated samples were noticed, although the electronic conductivities of the LMO samples were found to be higher than those of the LMNO samples. Indeed, the ionic conductivity of the CeO2 films and the optimal film thickness achieved by ALD helped overcome the trade-off between long cycle-life and the reduced initial capacity fade of the LMO when used as a cathode in lithium ion batteries.
Department(s)Mechanical and Aerospace Engineering
Research Center/Lab(s)Center for High Performance Computing Research
Document TypeArticle - Journal
Document VersionFinal Version
Rights© 2016 Royal Society of Chemistry, All rights reserved.
Citation InformationRajankumar L. Patel, Jonghyun Park and Xinhua Liang. "Ionic and Electronic Conductivities of Atomic Layer Deposition Thin Film Coated Lithium Ion Battery Cathode Particles" RSC Advances Iss. 101 (2016)
Available at: http://works.bepress.com/jonghyun-park/7/