Freeze gelation 3D printing of rGO-CuCo2S4 nanocomposite for high-performance supercapacitor electrodes

Multicomponent Co2O3@CoMo2S4 Core-Shell Structures as a Binder-Free Electrode for Cycling Stability Supercapacitors

Transitional bimetallic sulfides have garnered significant interest due to their versatile redox reactions, strong electrochemical activity, and cost-effectiveness. However, their low energy density and poor rate performance have hindered their use in energy storage systems. To overcome these challenges, we have developed a Co2O3@CoMo2S4 core-shell structure using a strategic design approach, serving as a conductive framework for supercapacitors. The innovative Co2O3@CoMo2S4 core-shell structure exhibits exceptional performance, achieving a specific capacitance of 4951.8 F g-1 at 1 A g-1 and retaining 90.85% cyclic stability after 5500 cycles, outperforming most reported transitional bimetallic sulfides. The Co2O3@CoMo2S4//AC supercapacitor achieves an energy density of 41.66 Wh kg-1 and a power density of 0.35 kW kg-1. Our research paves the way for the development of transitional bimetallic sulfides with core-shell structures that offer superior performance in supercapacitor applications, providing valuable insights for future advancements in the field.

Layer-by-Layer Inkjet-Printed Manganese Oxide Nanosheets on Graphene for High-Performance Flexible Supercapacitors

The widespread adoption of wearable, movable, and implantable smart devices has sparked the evolution of flexible, miniaturized power supplies. High-resolution inkjet printing of flexible microsupercapacitor (μSC) electrodes is a fast, inexpensive, and waste-free alternative manufacturing technology. In this work, a 2D birnessite-type manganese dioxide (δ-MnO2) water-based ink is used to print 10-25 layers of δ-MnO2 symmetrically on a preprinted interdigitated cell consisting of 10 layers of electrochemically exfoliated graphene (EEG). The cell with 10 printed layers of δ-MnO2 achieved the highest specific capacitance, energy density, and power density of 0.44 mF cm-2, 0.045 μW h cm-2, and 0.0012 mW cm-2, respectively. Since inkjet-printing technology supports μSC manufacturing with parallel/series connectivity, four cells were used to study and improve the potential window and capacitance that can be used to construct μSC arrays as power banks. This work provides the first approach for designing an inkjet-printed interdigitated hybrid cell based on δ-MnO2@EEG that could be a versatile candidate for the large-scale production of flexible and printable electronic devices for energy storage.

Current Trends and Promising Electrode Materials in Micro-Supercapacitor Printing

The development of scientific and technological foundations for the creation of high-performance energy storage devices is becoming increasingly important due to the rapid development of microelectronics, including flexible and wearable microelectronics. Supercapacitors are indispensable devices for the power supply of systems requiring high power, high charging-discharging rates, cyclic stability, and long service life and a wide range of operating temperatures (from -40 to 70 °C). The use of printing technologies gives an opportunity to move the production of such devices to a new level due to the possibility of the automated formation of micro-supercapacitors (including flexible, stretchable, wearable) with the required type of geometric implementation, to reduce time and labour costs for their creation, and to expand the prospects of their commercialization and widespread use. Within the framework of this review, we have focused on the consideration of the key commonly used supercapacitor electrode materials and highlighted examples of their successful printing in the process of assembling miniature energy storage devices.

Ternary Nanohybrid of Ni3S2/CoMoS4/MnO2 on Nickel Foam for Aqueous and Solid-State High-Performance Supercapacitors

To overcome the issues related to supercapacitor (SC) electrodes, such as high cost, low specific capacitance (C_s), low energy density (ED), requirements for expensive binder, etc., binderless electrodes are highly desirable. Here, a new ternary nanohybrid is presented as a binder-free SC electrode based on Ni₃S₂, CoMoS₄, and MnO₂. A facile two-step hydrothermal route, followed by a short thermal annealing process, is developed to grow amorphous polyhedral structured CoMoS₄ and further wrap MnO₂ nanowires on Ni foam. This rationally designed binder-free electrode exhibited the highest C_s of 2021 F g⁻¹ (specific capacity of 883.8 C g⁻¹ or 245.5 mAh g⁻¹) at a current density of 1 A g⁻¹ in 1 M KOH electrolyte with a highly porous surface morphology. This electrode material exhibited excellent cycling stability (90% capacitance retention after 4000 cycles) due to the synergistic contribution of individual components and advanced surface properties. Furthermore, an aqueous binder-free asymmetric SC based on this ternary composite exhibited an ED of 20.7 Wh kg⁻¹, whereas a solid-state asymmetric SC achieved an ED of 13.8 Wh kg⁻¹. This nanohybrid can be considered a promising binder-free electrode for both aqueous and solid-state asymmetric SCs with these remarkable electrochemical properties.

Facile synthesis of MnCo2S4 nanosheets as a binder-free electrode material for high performance supercapacitor applications

This paper reported an easy synthesis of MnCo2S4 (MCS) nanosheets by a one-pot solvothermal method for high performance supercapacitor electrode material applications. The obtained MCS nanosheets with an ultrathin thickness...

High electrochemical performance of ink solution based on manganese cobalt sulfide/reduced graphene oxide nano-composites for supercapacitor electrode materials

Large scale supercapacitor electrodes were prepared by 3D-printing directly on a graphite paper substrate from ink solution containing manganese cobalt sulfide/reduced graphene oxide (MCS/rGO) nanocomposites. The MCS/rGO composite solution was synthesized through the dispersion of MCS NPs and rGO in dimethylformamide (DMF) solvent at room temperature. Their morphology and composition were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray diffraction (EDS). The role of rGO on decreasing charge transfer resistance and enhancing ion exchange was discussed. The MCS/rGO electrode exhibits an excellent specific capacitance of 3812.5 F g⁻¹ at 2 A g⁻¹ and it maintains 1780.8 F g⁻¹ at a high current density of 50 A g⁻¹. The cycling stability of the electrodes reveals capacitance retention of over 92% after 22 000 cycles at 50 A g⁻¹.

Large scale supercapacitor electrodes were prepared by 3D-printing directly on a graphite paper substrate from ink solution containing manganese cobalt sulfide/reduced graphene oxide (MCS/rGO) nanocomposites.