Paper-based flexible supercapacitors with drawn van der Waals materials

Two-dimensional (2D) materials are widely used in various applications due to their extraordinary properties. In particular, their electrochemical stability, low electrical resistance, and huge specific surface area make them very interesting active materials for supercapacitors. Herein, flexible, biodegradable, and low-cost supercapacitors are introduced in a very simple way based on hand-drawing pencil traces or -rubbing molybdenum disulfide (MoS2), titanium trisulfide (TiS3) and franckeite traces on the paper. Results demonstrate that pencil-drawn paper has higher capacitance performance (∼6.39 F/g) among the suggested electrodes. Interestingly, the introduced MoS2/pencil, TiS3/pencil, and franckeite/pencil drawn paper electrodes reveal dramatic improvements with long cyclic life thanks to the occurrence of synergetic effects and higher available active cites within the heterostructures. Moreover, the assembled symmetric solid-state supercapacitors retain their performance even under applied bending, indicating their excellent potential for wearable/flexible applications.