Tungsten Bronze Anode Materials

At IREQ, besides the participation in the field tests run by the engineers of Hydro-Quebec (12), the main effort has been to tackle fundamental problems in the field of electrocatalysis (18-22) and of anodic oxidation of different potential fuels (23-26). A careful and extensive study of the electrochemical properties of the tungsten bronze has been carried out (18-20) the reported activity of these materials in acid media for the oxygen reduction could not be reproduced and this claim by other workers has been traced back to some platinum impurities in the electrodes. Some novel techniques in the area of electrode preparation are also under study (21,22) the metallic deposition of certain metals on oriented graphite show some interesting catalytic features for the oxygen reduction and also for the oxygen evolution reaction. 

The diffusion coefficients found in the LfcNao seWOs bronzes are of the order of magnitude from 10 to 10 cm s. Such a high values of the DC would eliminate the rate-capability limitations of the cathode material. So far, however, the high-rate LIB with tungsten bronze-based anode has not been reported. 

Slater PR, Irvine ITS (1999) Synthesis and electrical characterisation of the tetragonal tungsten bronze type phases, (BaySr/Ca/La)o.6MxNbi.x03.j (M = mg, ni, mn, cr, fe, in, sn) evaluation as potential anode materials for solid oxide fuel cells. Solid State Ionics 124 61-72... 

Kaiser A, Bradley JL, Slater PR, Irvine ITS (2000) Tetragonal tungsten bronze type phases (Sri.xBax)o.6Tio.2Nbo.803 d material characterisation and performance as SOFC anodes. Solid State Ionics 135 519-524... 

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