Self-Assembled 3D Graphene-Based Framework for Supercapacitor

Numerous interests have been attracted to establishing graphene-based materials for energy storage applications in the past decades [1, 2]. Constructing 3-dimensional graphene-based architectures provides a promising conductive skeleton and surface area for surface charge transfer and storage [3]. Herein, we report a simple self-assembled approach utilising surface electrostatic force between graphene oxide (GO) and trimolecular layered double hydroxide (LDH) nanoparticles to construct a hybrid 3D functionalised graphene framework via freeze-drying method for supercapacitor. Surprisingly, the synthesised GO-LDH hybrid material exhibits a typical electro-double layer capacitor (EDLC) rather than a battery electrochemical profile contributed by LDH material [4]. Our experimental study confirmed that the GO-LDH hybrid presents a relatively high specific capacitance of 278 F/g at 1 A/g and impressive rate capability (77.6%) at a high current density of 50 A/g in the aqueous working environment. We further investigated the surface structure to discuss the unexpected electrochemical profile of the material. This work provides a new insight into the fabrication and understanding of the GO-LDH hybrid 3D framework. A simple synthesis method, high reproducibility, and effective energy storage performance open a broad potential pathway for further applications.<br/><br/><b>Reference</b><br/>[1] Noori, A., El-Kady, M. F., Rahmanifar, M. S., Kaner, R. B., & Mousavi, M. F. (2019). Towards establishing standard performance metrics for batteries, supercapacitors and beyond. <i>Chemical Society Reviews</i>, <i>48</i>(5), 1272-1341.<br/>[2] Mohamed, N. B., El Kady, M. F., & Kaner, R. B. (2022). Macroporous graphene frameworks for sensing and supercapacitor applications. <i>Advanced Functional Materials</i>, <i>32</i>(42), 2203101.<br/>[3] Shao, Y., El Kady, M. F., Lin, C. W., Zhu, G., Marsh, K. L., Hwang, J. Y., ... & Kaner, R. B. (2016). 3D freeze casting of cellular graphene films for ultrahigh power density supercapacitors. <i>Advanced Materials</i>, <i>28</i>(31), 6719-6726.<br/>[4] Chen, S., Luo, J., Li, N., Han, X., Wang, J., Deng, Q., ... & Deng, S. (2020). Multifunctional LDH/Co9S8 heterostructure nanocages as high-performance lithium sulfur battery cathodes with ultralong lifespan. <i>Energy Storage Materials</i>, <i>30</i>, 187-195.