The fascinating features of 2D nanomaterials for various applications have prompted increasing research into single and few-layer metal dichalcogenides nanosheets using improved nanofabrication and characterization techniques. MoS₂ has recently been intensively examined among layered metal dichalcogenides and other diverse transition metal-based materials, that have previously been studied in various applications. In this research, we report mixed-phase Mn-doped MoS₂ nanoflowers for supercapacitor performance studies. The confirmation of the successfully prepared Mn-doped MoS₂ nanoflowers was characterized by XRD, SEM-EDS, RAMAN, and BET research techniques. The mixed-phase of the as-synthesized electrode material was confirmed by the structural changes observed in the XRD and RAMAN studies. The surface area from the BET measurement was calculated to be 46.0628 m²/g, and the adsorption average pore size of the electrode material was 11.26607 nm. The electrochemical performance of the Mn-doped MoS₂ electrode material showed a pseudo-capacitive behavior, with a specific capacitance of 70.37 Fg⁻¹, and with a corresponding energy density of 3.14 Whkg⁻¹ and a power density of 4346.35 Wkg⁻¹. The performance of this metal-doped MoS₂-based supercapacitor device can be attributed to its mixed phase, which requires further optimization in future works.

Metal–organic frameworks (MOFs) have gained significant attention as potential supercapacitor electrodes due to their high surface area, tunability, and well-defined porosity. However, their application is often limited by low capacity, poor electrical conductivity, and weak substrate adhesion, as observed in zeolitic imidazolate framework-67 (ZIF-67). To address these limitations, this study investigates the effect of nickel incorporation into ZIF-67, aiming to enhance its electrochemical performance. A series of hybrid-MOFs, denoted as ZIF-67 : Ni (1 : X), were synthesized via a simple solution-phase method at room temperature by varying the nickel content. Nickel was introduced to facilitate faster redox reactions and improve ion transport, thereby enhancing charge storage capability. The optimized ZIF-67 : Ni (1 : 2) electrode exhibited a high specific capacity of 161.2 mA h g⁻¹ at 1 A g⁻¹, with a capacity retention of 74.6% after 5000 charge–discharge cycles, outperforming pristine ZIF-67 and other nickel-mixture variants. The improved electrochemical performance is attributed to the enhanced porous structure, which increased active site accessibility and reduced charge transfer resistance. Furthermore, an asymmetric supercapacitor device assembled using ZIF-67 : Ni (1 : 2) as the positive electrode and activated carbon (AC) as the negative electrode (ZIF-67 : Ni (1 : 2)//AC) demonstrated a cell capacity of 44.6 mA h g⁻¹, a specific energy of 36.97 W h kg⁻¹, and a specific power of 416.3 W kg⁻¹ at 0.5 A g⁻¹. Notably, the device exhibited excellent cycling stability, retaining 99.8% of its capacity after 10 000 cycles at 10 A g⁻¹. These findings highlight the potential of multi-metallic interactions in enhancing the electrochemical performance of ZIF-67-based MOFs, offering valuable insights for the development of high-performance supercapacitor electrodes.

Tuning the structures, compositions and morphologies of metal–organic frameworks (MOFs) is critical to boosting their supercapacitor performances. In this study, a ligand-engineering strategy was adopted to fabricate ZnCo-bimetallic MOFs with unique properties using three different ligands (2-methylimidazole, terephthalic acid and 2-amino terephthalic acid) under the same synthesis protocol. The variation in the electron-donating ability of the three ligands gave rise to changes in their structural, morphological and electrochemical properties. Compared to other MOFs, the imidazole-based ZnCo-MOF (ZnCo-MOF-HMIM) with a dodecahedron morphology, good specific surface area and moderate pore characteristics provided considerable electron transport paths for ion migration on the electrode surface site, which guarantees a greater charge storage. Specifically, ZnCo-MOF-HMIM delivered the best specific capacity of 176.8 m h A g⁻¹ at 1 A g⁻¹ specific current and retains about 87.5% of its capacity at 10 A g⁻¹ after 5000 cycles. Furthermore, the asymmetric device achieved a specific energy of 28.2 W h kg⁻¹ at a specific power of 1025.4 W kg⁻¹ and demonstrates remarkable coulombic efficiency and capacity retention of 98.4% and 80.0% at 10 A g⁻¹ over 10 000 cycles respectively. The presence of an N donor atom in the imidazole ligand which imparts high hydrophobicity, and the synergistic effects of Zn and Co ions could predispose ZnCo-MOF-HMIM to have more active sites and greater stability for enhanced performance. This work provides insight into the key role of ligands in the formation mechanism of bimetallic MOFs for enhanced electrochemical energy storage.