Polyaniline nanofiber/vanadium pentoxide sprayed layer-by-layer electrodes for energy storage

Layer-by-layer assembly, as a low-cost process to create high-performance coatings, has been widely studied over the past 20 years. However, conventional layer-by-layer assembly is not well suited to large-area, large-scale and rapid application because of the long time scale required to complete a multilayer coating. Here, we develop a simple, water-based, rapid spray-on method to produce and prepare polyaniline/vanadium pentoxide layer-by-layer thin film cathodes for Li-ion batteries. This method uses spray-assisted LbL assembly, which is suitable to coating over large areas rapidly. The result is a water-processable hybrid cathode with high capacity (up to 232 mA h g(-1) at a discharge current of 5 mu A cm(-2)), specific energy (up to 650 mW h g(-1) at a discharge current of 0.5 mu A cm(-2)), specific power (up to 3395 mW g(-1) at a discharge current of 25 mu A cm(-2)), and good cycle life. The performance is dependent on thickness and discharge rate. Compared to the traditional polyaniline/vanadium pentoxide prepared by dipping at a rate of 0.0373 nm s(-1), sprayed electrodes grow at a significantly high rate of 0.42 nm s(-1) - 11 times faster. This approach demonstrates the rapid layer-by-layer assembly of Li-ion battery electrodes without sacrificing performance.