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Synthesis, Characterization and Properties of New Vanadia-Alumina and Vanadia-Silica Composites Prepared by Interpenetrating Polymer Network Approach Elaine C. Zampronio1, Glauciane N. Barbosa1, Carlos F.O. Graeff2, Tânia A.F. Lassali3 and Herenilton P. Oliveira1 1 Depto. de Química/FFCLRP, 2Depto. de Física e Matemática/FFCLRP, 3Lab. Resíduos Químicos/PCARP, USP, Av. Bandeirantes 3900, Ribeirão Preto (SP), 14040-901, Brasil.

ABSTRACT In this study, we incorporated vanadium pentoxide xerogel into an alumina matrix and into a silica matrix in order to improve the structural stability by incorporating the electroactive material into an inert matrix which provides structural stability to the electrode. The novel materials were characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectrometry, cyclic voltammetry and impedance spectroscopy. V2O5/SiO2 and V2O5/Al2O3 xerogel composites prepared by soft chemistry present conductivity almost five orders of magnitude higher than other related systems. The electrochemical behavior is quite similar to that found for V2O5 xerogel. In addition, the cyclic voltammetric and electrochemical impedance spectroscopy studies demonstrated that the alumina and silica matrices provide an improvement of the electrochemical properties mainly in relation to the kinetics of the lithium electroinsertion into the oxide matrix with little decrease of total charge during successive redox cycles. Overall, the synthetic approach applied in this study is extremely attractive due to its simplicity and can provide new strategies for tailoring new materials and future family members for electrochromic devices, batteries and chemical sensing.

INTRODUCTION The synthesis of novel multicomponent materials composed of transition metals in inorganic matrices has received growing attention over the past 10 years, in particular because they are attractive candidates in many fields of modern technologies. Homogeneous multicomponent materials composed of transition metals dispersed in a silica matrix have received attention due to their potential technological applications in heterogeneous catalysis, optics, sensors and batteries [1-3]. Concerning the last item, vanadium pentoxide xerogel is considered as a promising material for secondary Li batteries, since it combines a layered structure suitable for insertion reaction that makes the insertion and de-insertion of high quantities of Li+ per mole of cathode (host structure) with a mixed ionic-electronic conductivity [4]. However, the intercalation reaction involves solvent exchange and irreversible structural deformations that limit the rechargeability [5]. An approach to improve the structural stability is incorporating the electroactive material into an inert matrix, which provides structural stability to the electrode. Therefore, the idea is to incorporate vanadium pentoxide xerogel into an inorganic matrix retaining its lamellar structure and electrochemical proper