investigating MCM-41/metal-organic framework nanocomposites as silicon-containing electrodes for supercapacitor

Abstract

For both batteries and supercapacitors, developing electrodes based on Silicon is of enormous interest. The purpose of this study was to prepare two nanocomposites, MZ8 (MCM-41/ZIF-8) and MU66 (MCM-41/UiO-66), that have been specifically designed to function as electrode materials. The cyclic voltammograms showed enlarged potential window and galvanostatic charge-discharge by confirming the samples' successful synthesis process and morphological structure via XRD, FT-IR, TGA, BET, TEM, and FESEM plots gave excellent specific capacitance.

MU66 with spherical morphology and average particle size around 50 nm creates more appropriate pores, and more accessible pathways showed higher capacitance (992 F g ^− 1 @ 0.5 Ag⁻¹), while MZ8 (351 F g ^− 1 @ 0.5 Ag⁻¹) with hexagonal morphology and average particle size around 350 nm stands more durable (100%) after 4000 cycles. MZ8 displayed an EDLC with semi-rectangular CV and symmetric charge-discharge graphs, while MU66 showed inflation at lower sweep rates and lowered current densities, representing a hybrid charge mechanism. Based on the EIS test, MZ8 showed lower charge resistance and was more conducive to taking the barriers of the low capacitance of Si-based electrodes. We believe that the fabrication of Si-containing materials into MOFs can protect Si from swelling-shrinking and maintain close contact between Si and electrolyte to use both merits of MOF structures and Si capacity.