The growing demand for compact energy storage devices may be met through the use of thin-film microbatteries, 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 are deposited in films of 49 nm/layer pair thickness. The resulting composition was 77 wt % PNFs and 23 wt % MXenes. The charge storage process was deconvoluted into faradaic/non-faradaic contributions and separated into contributions from PNFs and MXenes. A sandwich cell showed a maximum areal capacity, energy, and power of 17.6 μA h cm-2, 22.1 μW h cm-2, and 1.5 mW cm-2, respectively, for PNF/MXene multilayers of about 2 μm thickness. This work suggests the possibility of using LbL PNF/MXene thin films as electrode materials for thin-film energy storage devices used in next-generation small electronics.
Bibliographical noteFunding Information:
This material is based in part upon work supported by the National Science Foundation under grant 1760859. The authors also thank Texas A&M Energy Institute for financial support. Professor Zi appreciates support of the Basic Science Research Program through the National 13 Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (no. 2017002988), and the Korea University Grant.
Copyright © 2019 American Chemical Society.
- layer-by-layer assembly
- polyaniline nanofiber
- thin-film energy storage
ASJC Scopus subject areas
- General Materials Science