Abstract
AbstractMixed transition‐metal oxide spinels exhibit high electrical conductivity and enhanced infrared transmissivity resulting from the presence of small polarons in the NiCo2O4 lattice. Polarons are formed as a result of judicious choice of component metal cations and attendant resident cation charge states. Substitution of lithium for cobalt (Ni1+xCo2−x−zLizO4) while maintaining the spinel stoichiometry and controlled post‐deposition annealing was found to influence measured conductivity in both solution‐ and sputter‐deposited thin films. For lithium concentrations < 10% an improvement in conductivity was observed, depending upon whether the oxide film was deposited from solution (large increase) or sputter deposited (small increase). However, higher lithium concentrations degraded conductivity. Both XPS and SIMS analyses of films with high lithium concentrations (z > 0.3) revealed that lithium was concentrated near the film surface and the formation of carbonate was detected by XPS and Fourier transform infrared data. Results indicate that additions of lithium to transition‐metal spinel oxides can lead to increased conductivity by increased polaron formation. However, in high concentration, lithium is an interstitial that diffuses to the surface to form compounds that degrade electrical conductivity. Copyright © 2005 John Wiley & Sons, Ltd.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
