Direct-Ink-Write 3D Printing of Programmable Micro-Supercapacitors from MXene-Regulating Conducting Polymer Inks

3D printing is gaining prospects thanks to the ease of manufacturing energy storage devices with programmable geometry at the macro- and microscales. Herein, a direct ink writing 3D printing approach for preparing all-printed flexible micro-supercapacitors is demonstrated using rationally designed poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/MXene composite gels as inks without the tedious processes and toxic organic additives. Among the printable inks, the homogeneously distributed MXene nanosheets can boost the printability of PEDOT:PSS solution and also regulate the interconnected electronic structures of the PEDOT:PSS undergoing a micellar to linear structure transition. The resulting 3D printed micro-supercapacitors and integrated devices can deliver exceptionally large areal capacitances, remarkable rate performance, and high cycling stability with thickness-independent capacitances even under exceptional deformations and low temperatures. This study thus provides a simple yet environmental-friendly approach for preparing the conducting-polymer-based inks for 3D printing of customized, multiscale, and integrated energy devices.

Automated summary

A direct ink writing 3D printing approach was used to prepare all-printed flexible micro-supercapacitors using rationally designed PEDOT:PSS/MXene composite gels as inks. The MXene nanosheets in the printable inks can enhance the printability of PEDOT:PSS solution and modulate the electronic structures of PEDOT:PSS during a structure transition. The resulting 3D printed micro-supercapacitors and integrated devices exhibit large capacitances, excellent rate performance, and high cycling stability even under exceptional deformations and low temperatures.