High-Energy-Density Asymmetric Supercapacitor Based on a Durable and Stable Manganese Molybdate Nanostructure Electrode for Energy Storage Systems

Abstract

3D interconnected MnMoO 4 nanosheet arrays with abundant open spaces and ordered arrangements deposited on nickel foam (NF@MnMoO 4 ) are fabricated by a mild one-step hydrothermal method. As an integrated binder-free electrode for supercapacitors, the optimized NF@MnMoO 4 electrode exhibits a superhigh specific capacitance of 4609 F g −1 (640 mAh g −1 ) at a current density of 1 A g −1 , remarkable rate capability (2800 F g −1 (388.89 mAh g −1 ) even at a current density as high as 20 A g −1 ), and outstanding cycling stability (92.4% of the initial specific capacitance after 20,000 cycles). The fabricated NF@MnMoO 4 //AC asymmetric supercapacitors (ASCs) with excellent cycling performance and high Coulombic efficiency achieve an ultrahigh energy density of 107.38 Wh kg −1 at a power density of 801.34 W kg −1 (72.18 Wh kg −1 at a power density of 3987.85 W kg −1 ). As the practical application, the self-charging power packs of commercial solar cells and NF@MnMoO 4 //AC ASCs are demonstrated to power an LED without extra recharging by other devices, indicating their promising applications in self-power energy-harvesting storage systems.

Interfacially coupled thin sheet-like NiO/NiMoO4 nanocomposites synthesized by a simple reflux method for excellent electrochemical performance

“…8b), which is consistent with the previous studies. 16,35,39 From Fig. 8b, we can also see that diffusive contributions dominate over the capacitive part in the entire scan rate range, indicating the efficient ion intercalation possibility of the electrode material and typical battery-type behaviour.…”

“…Furthermore, better kinetic analysis of the charge storage contributions involving the capacitive and diffusive processes is conducted on the basis of the entire CV curves at different scan rates (from 2 to 100 mV s −1 ). 16,35,39 Fig. 8a shows the representative CV curve of the NNMO-3 electrode at 30 mV s −1 along with the surface-based capacitive controlled process separated as the blue region, which is ∼20.5% of the overall storage capacity.…”

“…show improved electronic conductivity along with the existence of multiple oxidation states due to the synergistic attributes of bimetallic components for superior electrochemical performance and therefore are explored as one of the promising pseudocapacitive electrode materials in storage devices. 14–16 NiMoO 4 (NMO), in particular, shows better prospects and is therefore widely reported due to its high theoretical specific capacitance (∼2500 F g −1 ), reasonably good electrical conductivity due to the presence of Mo, chemical inertness, low toxicity, low cost, and the availability of multiple oxidation states. 14,15,17–19 NMO commonly forms two polymorphs having a monoclinic structure with the space group C 2/ m at atmospheric pressure: α-NMO (low temperature) and β-NMO (high temperature).…”

The Application of Metal–Organic Frameworks and Their Derivatives for Supercapacitors

“…Several conclusions can be collected: (i) MOFs derived metal sulfide displayed an extraordinary electronic performance, especially the trimetal sulfide composites. Binder-free Ni foam (providing Ni source)-supported NiCo-S/NF (a mixture of NiCo 2 S 4 , Co(OH) 2 and Ni 3 S 2 ) derived from ZIF-67 exhibits the highest specific capacitance of 3724 F g −1 , at a current density of 1 A g −1 , among all the discussed materials in the work [ 103 ], lower than recently reported MnMoO 4 /NF with a super-high specific capacitance of 4609 F g −1 at a current density of 1 A g −1 , synthesized from non-MOF-involved hydrothermal procedure (reactants: MnCl 2 ·4H 2 O and Na 2 MoO 4 ·2H 2 O) [ 115 ]; (ii) MOFs-derived metal oxide manifested a remarkable electronic performance, as well. Notably, the Ni/Mn-PTA//AC SC device (assembled by the flower-like ultrathin MnNi 2 O 4 nanosheet derived from Ni/Mn-PTA as the positive electrode and AC as the negative electrode) yielded the largest energy density of 142.8 Wh kg −1 at the power density of 800 W kg −1 , overwhelming most previously reported SCs electrode materials [ 98 ]; (iii) most of MOFs-derived porous C exhibits specific capacitance smaller than 1000 F g −1 , while a combination with metal sulfide (MoS 2 , NiS, etc.)…”

Fiber Electrodes Mesostructured on Carbon Fibers for Energy Storage

“…In this sense, incorporating porous materials containing three-dimensional (3D) arrays of well-defined pores is an intriguing option. Self-assembled colloidal crystals were fabricated to serve as a scaffold for the formation of 3D meso- and nanostructured electrodes for rechargeable batteries − and supercapacitors. − They have demonstrated improvements in rate performance, benefiting from a large surface area, rapid ion transport, and efficient electron pathways. In particular, this approach enables controllable, deterministic electrode design by tuning the porosity, pore diameter, and thickness of the active materials …”