Layer-by-layer Assembly of Polyaniline Nanofiber and MXene Thin Film Electrodes for Electrochemical Energy Storage

Growing demand for compact energy storage devices may be met through the use of thin film micro batteries, which generally rely on charge storage in thin or conformal layers. A promising technique for creating thin film electrodes is layer-by-layer (LbL) assembly, based on the alternating adsorption of oppositely charged species to a surface to form a nanostructured electrode. Thin film energy storage devices must have a high energy density within a limited space, so new electrode structures, materials, and assembly methods are important. To this end, both two-dimensional MXenes and polyaniline nanofibers (PNFs) have shown promising energy storage properties. Here, we report on the LbL assembly of positively charged PNFs and negatively charged Ti3C2Tx MXenes into hybrid electrodes for thin film energy storage devices. The successful assembly is demonstrated in which MXenes and PNFs deposited in films of 49 nm/layer pair thick. The resulting composition was 77 wt% PNFs and 23 wt% MXenes. The charge storage...