Surfactant-Free Vanadium Oxides from Reverse Micelles and Organic Oxidants: Solution Processable Nanoribbons with Potential Applicability as Battery Insertion Electrodes Assembled in Different Configurations

Vanadium oxides similar to other metal transition oxides are prototypes of multifunctionality. Implementing new synthesis routes that lead to dry vanadium oxide nanomaterials with good functional and structural properties as well as good processing capabilities is thus of general interest. Here we report a facile method based on reverse micelles for the growth at room temperature and atmospheric pressure of surfactant-free vanadium oxide nanoribbons that retain after drying excellent solution-processable capabilities. Essential for the success of the method is the use of a soluble organic oxidant that acts as oxidant and cosurfactant during the synthesis, and facilitates surfactant removal with a simple washing protocol. Interestingly, this simple surfactant removal protocol could be of general applicability. As a proof-of-concept of the functional, structural, and processing capabilities of the dry vanadium oxide nanoribbons here prepared, we have checked their lithium insertion capabilities as battery cathodes built upon different configurations. Specifically, we show efficient insertion both in dry nanoribbons processed as films using doctor blade and organic solvents and in dry nanoribbons infiltrated in three-dimensional metal collectors from aqueous suspensions.