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a) CV curves of MoOx‐BA‐3, MoOx‐DDA‐3, and MoOx‐HDA‐3 electrodes measured at 10 mV s⁻¹. b) GCD curves of MoOx‐BA‐3, MoOx‐DDA‐3, and MoOx‐HDA‐3 electrodes measured at 1 A g⁻¹. c) Specific capacitance of MoOx‐BA‐3, MoOx‐DDA‐3, and MoOx‐HDA‐3 electrodes measured at various current densities. d) XRD patterns of pure MoO3 and the intercalated MoO3 before and after carbonization. e) XRD patterns of MoOx‐BA‐3, MoOx‐DDA‐3, and MoOx‐HDA‐3. f) Interlayer spacings of pure MoO3, MoOx‐BA‐3, MoOx‐DDA‐3, and MoOx‐HDA‐3 at (020). Core‐level Mo 3d XPS spectra of g) MoOx‐BA‐3, h) MoOx‐DDA‐3, and i) MoOx‐HDA‐3.
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Aqueous supercapacitors show advantages of high safely, prolonged lifespan, and low cost, etc. but there have never been commercial market products, nor quantitative investigation of practical pouch devices of aqueous supercapacitors. Herein, to achieve their lab‐scale to real‐life manufacture, a unique MoOx for supercapacitor use is constructed by...
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This systematic review covers the developments in aqueous aluminium energy storage technology from 2012, including primary and secondary battery applications and supercapacitors. Aluminium is an abundant material with a high theoretical volumetric energy density of –8.04 Ah cm−3. Combined with aqueous electrolytes, which have twice the ionic storag...
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... According to the Bragg equation, the layer spacing expanded from 0.32 nm to 0.40 nm. There were no other detectable peaks corresponding to metallic Mn or its compounds, confirming the ultra-low content of Mn atoms [21,22]. The extremely similar patterns of different samples demonstrated that the doped Mn atoms did not damage the main structure of the N/F co-doped carbon materials [23]. ...
Aqueous supercapacitors have occupied a significant position among various types of stationary energy storage equipment, while their widespread application is hindered by the relatively low energy density. Herein, N/F co-doped carbon materials activated by manganese clusters (NCM) are constructed by the straightforward experimental routine. Benefiting from the elevated conductivity structure at the microscopic level, the optimized NCM-0.5 electrodes exhibited a remarkable specific capacitance of 653 F g−1 at 0.4 A g−1 and exceptional cycling stability (97.39% capacity retention even after 40,000 cycles at the scanning rate of 100 mV s−1) in a neutral 5 M LiCl electrolyte. Moreover, we assembled an asymmetric device pairing with a VOx anode (NCM-0.5//VOx), which delivered a durable life span of 95% capacity retention over 30,000 cycles and an impressive energy density of 77.9 Wh kg−1. This study provides inspiration for transition metal element doping engineering in high-energy storage equipment.
... Among various electrochemical energy storage devices, sup ercapacitors (SCs) have received widespread attention because of their advantages including higher power density, faster charge/discharge capability, longer cycle life and lower cost than their metal-ion battery counterpart [4][5][6][7][8][9][10][11][12][13][14]. More importantly, the SCs based on aqueous electrolytes have some unique advantages such as higher safety, larger ionic conductivity (>100 mS cm − 1 ), lower cost and more environmental friendliness, as compared with the ones based on organic electrolytes [15][16][17][18][19][20]. However, the relatively low energy density (E) of SCs, compared with batteries, limits the extension of their application scenarios [21,22]. ...
In this paper, we report a cathode with the good comprehensive electrochemical performance by electrochemically growing MnCoP nanosheets on NiCo2O4 nanograss hydrothermally grown on carbon nanotube (CNT)-coated Ni foam. A capacitance of 4787.3 mF cm−2 at 1 mA cm−2, high rate performance (3126.2 mF cm−2 at 30 mA cm−2), as well as good cycle stability is delivered by the cathode. By employing this cathode, the anode of activated carbon on carbon cloth, and the electrolyte of 2 M KOH aqueous solution, we assembled an aqueous asymmetric supercapacitor, which exhibits an energy density of 0.390 mWh cm−2 at 0.825 mW cm−2 and good cycle stability of 85.7 % capacitance retention after 20,000 cycles at 10 mA cm−2.
... In recent years, the speed of human consumption of resources is much faster than the speed of resource generation. In the long term, human will fall into the dilemma of energy shortage, and the vision of developing new energy storage devices is constantly enhanced [1][2][3][4]. Batteries and supercapacitors as examples of modern energy storage technology convert chemical reactions into electric energy by using materials with abundant reserves, thus relieving the traditional situation of simply relying on oil and coal for energy supply [5]. Supercapacitors have been widely concerned owing to their ultra-high power density and outstanding cycle stability and have been applied in life and even industry, such as port cranes, oil eld drilling machines and other equipment or e cient green power energy. ...
Prussian blue analogues (PBAs) have the advantages of stable electrochemical performance and long service life when used as energy storage materials due to their face‒centered cubic structure. Here, Ni‒Co Prussian blue analogue (PBA) nano units have been utilized as precursor to prepare corresponding metal sulfide derivatives, which inherited the structural properties of the precursor. This unique structural exposes more reaction sites and the generation of a small amount of nitrogen-doped carbon that enhances charge transfer. This cube structure has a buffer effect on the stress of the active substance during charging and discharging. The CoS 2 /Ni 3 S 4 ‒N‒C provides a capacitance of 817 C g ‒1 at 3 A g ‒1 and there is still 556 C g ‒1 at 20 A g ‒1 . Furthermore, CoS 2 /Ni 3 S 4 ‒N‒C electrode yields outstanding cycle stability (98.2% capacitance retention at 10,000 cycles). An asymmetric supercapacitor (ASC) device consisting of CoS 2 / Ni 3 S 4 ‒N‒C and activated carbon electrodes have an energy density of 40 Wh kg ‒1 , and a retention rate of 103.7% for 10,000 cycles at 10 A g ‒1 , presenting excellent cycle stability. The electron properties of Co 2 NiO 4 and CoS 2 /Ni 3 S 4 − N−C are compared by density functional theory (DFT). CoS 2 /Ni 3 S 4 − N−C detects more DOS near the Fermi level, leading to larger charge accumulation, indicating that the electron conductivity of the heterojunction is much higher than that of the oxide, and eventually faster reaction kinetics can be obtained.
In this present research, we synthesized pure α‐Fe2O3, NiO, and a microporous α‐Fe2O3@NiO heterostructure electrode via the spray pyrolysis method. The microporous α‐Fe2O3@NiO heterostructure electrode, with its highly porous structure, offers a larger electrode‐electrolyte interface, which results in improved electrochemical performance. Specifically, the microporous heterostructure exhibited a higher specific capacitance of 530.87 F/g at a current density of 7 mA/cm² in a 1 M NaOH electrolyte, as compared to α‐Fe2O3 (187.12 F/g at 7 mA/cm²) and NiO (492.69 F/g at 7 mA/cm²). The microporous α‐Fe2O3@NiO heterostructures exhibited significantly enhanced electrochemical performance as compared to the individual α‐Fe2O3 and NiO samples, owing to the synergistic effect of the heterostructure. Furthermore, the microporous α‐Fe2O3@NiO heterostructure exhibited high specific capacitances and exceptional cycling stability for more than 2000 cycles, indicating their potential as excellent electrode for supercapacitor devices.
The development of cost‐effective and stable electrocatalysts that can replace the prevailing Pt‐based and Ir‐based catalysts for water splitting remains a formidable challenge. The electrocatalytic performance of a catalyst depends on its chemical composition and environment during catalysis. Herein, a Ru–Mo composite is used as an example to highlight the significance of tailoring the chemical environments of the active‐sites. This customization enhances the cathodic and anodic reactions involved in water splitting, ultimately leading to an improved full reaction efficiency. Specifically, the chemically reduced state of Ru–Mo demonstrates promising hydrogen evolution activity and exhibits low overpotentials of 48 and 34 mV at the current density of 10 mA cm ⁻² in acidic and alkaline electrolytes, respectively. The chemically oxidized state of Ru–Mo, derived from the same precursor, demonstrates proficient oxygen evolution activity and exhibits low overpotentials of 260 and 270 mV at 10 mA cm ⁻² in acidic and alkaline electrolytes, respectively. Additionally, in both cases, the Ru–Mo composites exhibit significantly improved stability under typical water‐splitting conditions. Despite the close chemical compositions of these two catalysts, they show poor performance in the counter electrode reactions, demonstrating the importance of establishing a suitable chemical environment for efficient electrocatalysis.
Vanadium trioxide (V6O13) cathode has recently aroused intensive interest for aqueous zinc‐ion batteries (AZIBs) due to their structural and electrochemical diversities. However, it undergoes sluggish reaction kinetics and significant capacity decay during prolonged cycling. Herein, an oxygen‐vacancy‐reinforced heterojunction in V6O13−x/reduced graphene oxide (rGO) cathode is designed through electrostatic assembly and annealing strategy. The abundant oxygen vacancies existing in V6O13−x weaken the electrostatic attraction with the inserted Zn²⁺; the external electric field constructed by the heterointerfaces between V6O13−x and rGO provides additional built‐in driving force for Zn²⁺ migration; the oxygen‐vacancy‐enriched V6O13−x highly dispersed on rGO fabricates the interconnected conductive network, which achieves rapid Zn²⁺ migration from heterointerfaces to lattice. Consequently, the obtained 2D heterostructure exhibits a remarkable capacity of 424.5 mAh g⁻¹ at 0.1 A g⁻¹, and a stable capacity retention (96% after 5800 cycles) at the fast discharge rate of 10 A g⁻¹. Besides, a flexible pouch‐type AZIB with real‐life practicability is fabricated, which can successfully power commercial products, and maintain stable zinc‐ion storage performances even under bending, heavy strikes, and pressure condition. A series of quantitative investigation of pouch batteries demonstrates the possibility of pushing pouch‐type AZIBs to realistic energy storage market.
