In-situ grown bimetallic FeCu MOF-MXene composite for solid-state asymmetric supercapacitors

Abstract

MXene (2D titanium carbide) is thoroughly investigated and studied in recent years for energy storage purposes. It has excellent properties such as hydrophilicity, metallic conductivity especially high surface redox reactivity which is crucial for energy storage applications. Despite these extraordinary properties, there are some shortcomings that significantly affect the electrochemical performance of MXene such as restacking of MXene sheets. To prevent restacking of MXene sheets, the gaps between them should be filled with suitable material. Metal organic frameworks (MOFs) have also been thoroughly studied for electrochemical applications. Owing to their high crystallinity, porous structure, and surface area, MOFs have been utilized in various applications. Since pristine MOFs as electrode materials manifest lower specific capacity as well as rate capability; therefore it is preferable to synergize them with other appropriate materials. Herein, a unique strategy is proposed to develop a composite between MXene and FeCu bimetallic MOF. Thus, not only ion/electron diffusion pathways can be shortened but it can also improve electroactive sites. Resultantly, MXene was prevented from sheet restacking, whereas bimetallic MOFs with MXene composite rendered excellent specific and rate capacity. The as prepared FeCu MOF/MXene electrode gave high values of specific capacity ∼440 mA h g−1 in three electrode configurations. Whereas the as prepared MXene-FeCuMOF//AC ASC manifested high cyclic stability of 89 % after 10,000 alternate GCD cycles. This study proposes a special route to effectively synergize MOFs with MXene and grow it on nickel foam (NF) in a binder free synthesis method.