Charge Storage Capability in Nanoarchitectures of V₂O₅/Chitosan/Poly(ethylene oxide) Produced Using the Layer‐by‐Layer Technique

Abstract

Abstract The electrochemical and electrochromic properties of layer‐by‐layer nanoarchitectures of V 2 O 5 /chitosan and V 2 O 5 alternated with a blend of poly(ethylene oxide) (PEO) and chitosan have been examined. Using a blend was important, since multilayers of PEO/V 2 O 5 could not be built. The number of electrochemically active V 2 O 5 sites was estimated to be around 3.4 × 10 –8 mol cm –2 and 4.4 × 10 –8 mol cm –2 for V 2 O 5 /chitosan and V 2 O 5 /blend, respectively, based on the UV‐vis absorbance attributed to the intervalence V 4+ →V 5+ transfer. A pronounced effect from PEO was observed in the migration/diffusion process, according to cyclic voltammetry and impedance spectroscopy data. The charges injected were 3.29 mC cm –2 and 8.02 mC cm –2 for V 2 O 5 /chitosan and V 2 O 5 /blend, respectively, at 20 mV s –1 . For V 2 O 5 /blend, the chronopotentiometric curves show that x in Li x V 2 O 5 is about 1.77. Evidence of enhanced ionic transport was provided by the Fourier transform infrared (FTIR) spectrum, which indicated lithium complexation by PEO and formation of a larger amorphous phase of PEO within the V 2 O 5 matrix. The importance of these results for the production of Li secondary microbatteries and electrochromic devices is discussed.