3D Printed MXene Micro-Supercapacitors with Ultra-High Energy Density

Abstract

Small scale energy storage devices are expected to play a significant role in the future advances of portable electronics, wireless sensors, and multifunctional micro/nanosystems. A crucial requirement for the fabrication of energy storage devices with high energy and power densities is using electrode materials with superior electrochemical properties. Another important requirement is the assembly of the electrode materials into structures that promote high ionic and electronic conductivities. In this talk, we report a scalable printing method for fabrication of on-chip three-dimensional (3D) micro-supercapacitors based on a class of 2D transition metal carbides called MXenes as electrode materials. MXenes offer high electronic conductivity and high specific capacitance and therefore, have attracted much interest as high-performance electrode materials for supercapacitors. In our work, the fabrication of MXene electrodes and device assembly is achieved using an extrusion-based 3D printing process that uses viscoelastic water-based MXene ink. A programmable printing machine was used in the printing process which involved layer-by-layer deposition of the MXene ink to fabricate the 3D electrodes. The developed printing method allows rapid fabrication of micro-supercapacitors on a variety of substrates, while electrode height can be controlled by the number of deposited layers. All-solid-state devices printed on flexible substrates showed excellent electrochemical performances under different bending conditions and delivered extremely high areal capacitances (over 1035 mF cm-2). Our study suggests that due to its high electronic conductivity and electrochemical properties, MXene is an excellent electrode material for the fabrication of 3D energy storage devices