作者：Lianghao Yu1, Zhaodi Fan1, Yuanlong Shao2, Zhengnan Tian1, Jingyu Sun1, & Zhongfan Liu1,3
单位：1. College of Energy, Soochow Institute for Energy and Materials Innovations (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, P. R. China
2. College Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
3. Center for Nanochemistry (CNC), College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing, P. R. China
摘要：Printing is regarded as a revolutionary and feasible technique to guide the fabrication of versatile functional systems with designed architectures. Two-dimensional (2D) MXenes are nowadays attractive in printed energy storage devices. However, owing to the van der Waals interaction between the MXene layers, the restacking issues within the printed electrodes can significantly impede the ion/electrolyte transport and hence handicap the electrochemical performances. Herein, we demonstrate a melamine formaldehyde templating method to develop crumpled nitrogen-doped MXene (MXene-N) nanosheets. The nitrogen-doping boosts the electrochemical performances of MXene via enhanced conductivity and redox activity. Accordingly, two types of MXene-N inks are prepared throughout the optimization of the ink viscosity to fit the 2D screen printing and three-dimensional (3D) extrusion printing, respectively. As a result, the screen printed MXene-N micro-supercapacitor delivers an areal capacitance of 70.1 mF cm−2 and outstanding mechanical robustness. Furthermore, 3D-printed MXene-N based supercapacitor manifests an areal capacitance of 8.2 F cm−2 for a 3-layered electrode, and readily stores a high areal energy density of 0.42 mWh cm−2. Our approach to harnessing such versatile MXene-N inks offers distinctive insights into the printed energy storage systems with high areal energy density and large scalability.