CORROSION RESEARCH CENTER Sensors and Batteries

The aerogel (ARG) material is prepared through a somewhat complicated procedure involving a supercritical drying step which limits somewhat its processing in a continuous manner. To simplify the procedure, we developed a new process that allowed us to quickly and easily synthesize larger amounts of V₂O₅ ARG- like material in subcritical conditions. The material has a surface area of about 200 m²/g, with pore size distributions that are shifted toward larger pores than the aerogel. The new material has shown by electrochemical tests a very good lithium insertion capacity.

The maximum delivered capacity for this material is 410 mAh/g at C4Li/40 rate, corresponding to a cathodic current of 14 mA/g. At higher discharge rates correspond a decrease of the cathode utilization, but without dramatic decreases. As best seen in Figure 1 for a rate change of a factor of ten, from C4Li/40 to C4Li/4, the specific capacity decreased only by 25%. At the latter rate, corresponding to a specific current of 141 mA/g and to a current density of 1.3 mA/cm², a specific capacity larger than 300 mAh/g was obtained. At higher rate (C4Li; 565 mA/g; 5.2 mA/cm) the hex.V₂O₅ composite electrode showed a somewhat lower specific capacity around 140 mAh/g, which is still very high when compared with other, already commercialized, electrode materials.

The composite material shows good cycling performance with a capacity fading upon repetitive galvanostatic intercalation and deintercalation cycles, below 0.5%.

RECENT PUBLICATIONS

"High Surface Area V₂O₅ as Host Material for Lithium Intercalation" F. Coustier, S. Passerini and W.H. Smyrl. Proceedings of the ECS Meeting in Montreal May 1997.

"A 400 mAh/g Low Capacity Fading Cathode for Rechargeable Lithium Batteries" F. Coustier, S. Passerini and W.H. Smyrl. Short communication in the Journal of Electrochemical Society, submitted June 1997.

"High Surface Area V₂O₅ Aerogel Intercalation Electrodes" D.B.Le, S.Passerini, J.Guo, J.Ressler, B.B.Owens and W.H.Smyrl. Journal of Electrochemical Society, 143, 2099 (1996).

"Aerogels and Xerogels of V₂O₅ as Intercalation Hosts" D.B.Le, S.Passerini, A.L.Tipton, B.B.Owens and W.H.Smyrl, Electrochemical Society Proceedings. Volumes 95-29 (1995) 86.

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CRC AREAS OF RESEARCH

• Aqueous Corrosion
• Atmospheric Corrosion
• Fuel Cells
• High Temperature Corrosion
• High Resolution Techniques
• Sensors and Batteries

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