Sol-gel synthesis and electrical characterization of doped-carbon decorated mixed conductor ceramics

TERNY, S.; VEGA-CASTILLO, J.; DE LA RUBIA, M.A.; DE FRUTOS, J.; FRECHERO, M.A.

MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY

ELSEVIER SCIENCE BV

Año: 2019 vol. 241 p. 66 - 74

0921-5107

New mixed composite conductors of compositions: Li 3 V 2−x [Cu] x (PO 4 ) 3 /C and Li 3 V 2−x [Nb] x (PO 4 ) 3 /C (x = 0.1; 0.2 and 0.3) have been synthesized by the sol-gel method using Citric and Oxalic acids as a primary carbon source and Carbon Black or Carbon Nano-Fibers as secondary carbon sources. The combination of these carbon forms with the Nb doped-polyanion material boosts their electrical behavior up to 10 −3 S.m −1 that is two orders of magnitude higher than the Li 3 V 2 (PO 4 ) 3 /C at a room temperature. SEM, TEM and Micro-Raman Spectroscopy evidence that Carbon Nano-Fiber blend is better conductor than Carbon Black blend, which is also revealed by complex conductivity spectra. The conductivity behavior of Nb-doped ceramic is better than the Cu-doped one. The obtained niobium composites have a much more stable structure compared to the copper ones because the niobium atoms fit well in the vanadium position, whereas copper atoms are expelled from the structured.