Electrical study of cathodic activation and relaxation of La0,80Sr0,20MnO3

Abstract

The effect of cathodic activation of sprayed La 0.8 Sr 0.2 MnO 3 (LSM) films has been studied by electrochemical spectroscopy impedance (EIS). LSM powder was prepared by a citrate route and X-ray diffraction analyses show a complete LSM crystallization without La 2 O 3 or La (OH) 3 as side products. Porosity and grain size estimated from scanning electronic microscopy gave values of 33% and 100 nm, respectively. EIS measurement was performed on a Pt/yttria-stabilized zirconia/LSM cell before and after a cathodic current load (300 mA/cm 2 ) on LSM electrode. The relaxation process, which is time-dependent, has been investigated. A drastic decrease of the electrode resistance was noticed just after applying the cathodic current, but after 9 h at optimized valence configuration in air at 850°C, the recorded polarization resistance gradually enhanced until it almost reached the initial value. The resulting diagrams have been fitted using a Gerischer associated with a resistor and constant phase elements. This simple method has permitted us to observe that only the electrode interfaces are modified by a cathodic activation and the microstructure remains nearly constant.

Study of mechanochemically prepared nanocrystalline La0.8Sr0.2MnO3

“…with minimum crystallite size exhibits maximum lattice expansion. Such lattice expansion has been demonstrated for ultrafine hematite crystallite in which uniform elastic expansion of lattice took place due to the effect of the action of the adjoining surface tension forces [28]. In contrast, there is not much lattice expansion seen for LSM-6-7-(unsint.)…”

“…The LSM have been chiefly synthesized by solid-state reaction [22] and chemical solution methods [23][24][25][26]. Other techniques, which have been used in recent past to prepare them, include citrate gel process [27,28], sol-gel process [29,30], co-precipitation [31], combustion synthesis [32,33], drip pyrolysis [29], oxalate co-precipitation [29], sonication-assisted co-precipitation [34,35], etc. In more recent past, Zhang and Saito [36] have synthesized LaMnO 3 by grinding the mixture of La 2 O 3 , MnO 2 , and Mn 2 O 3 powders at the room temperature using a high-energy ball mill.…”

A Brief Description of High Temperature Solid Oxide Fuel Cell’s Operation, Materials, Design, Fabrication Technologies and Performance

“…performance. This problem can be resolved by increasing the Mn concentration and keeping fabrication temperature <1300 °C [10,12,42,[45][46][47][48][49][50]. LSM has negligible oxygen ion conductivity at 900 °C with high electronic conductivity.…”

“…The bulk pathway is an accepted mechanism in mixed ionic electronic conductor (MIEC) and while electrolyte surface pathway is considered in composite materials like LSM/YSZ [10,38]. Figure 3 represents three pathways of oxygen reduction A lot of efforts/concentrations are being given to increase the performance of electrode for low and intermediate temperature SOFCs [10,37,39,40,[42][43][44][45][46][47]. A number of cathode materials having better electronic/ionic conductivity and increased oxygen exchange rate are investigated.…”

Effect of La 0.8 Sr 0.2 MnO 3 powder addition in the precursor solution on the properties of cathode films deposited by spray pyrolysis

“…One reason for this phenomenon is related to the contraction of the interstitial lattice parameter of manganese and the concomitant generation of oxygen vacancies on the surface of LSM electrode. The oxygen vacancies promote the active sites on LSM surface by favoring the dissociative adsorption and the oxygen diffusion on electrode surface [28][29][30].…”