Metal sulfides are of great interest for future electrode materials in supercapacitor and solar cell applications owing to their superior electrochemical activity and excellent electrical conductivity. With this scope, a binary transition metal sulfide (CoS) is prepared via one-step hydrothermal synthesis. Hexagonal phase of CoS with space group of P6/mmc(194) is confirmed by XRD analysis. Additional cubic CoS phase in the prepared sample originates the mixed valence state of Co (Co and Co) is affirmed from XPS analysis. Morphological features are visualized using HRSEM images that shows nanoflower shaped star-anise structure. Employing the prepared CoS as active electrode material, interfacial charge transport kinetics is examined by EIS-Nyquist plot. The supercapacitive performances are tested in two and three-electrode system which exhibited respective specific capacitances of 57 F/g and 348 F/g for 1 A/g. Further, the fabricated asymmetric CoS//AC supercapacitor device delivers an appreciable energy density of 15.58 Wh/kg and power density of 700.12 W/kg with excellent cyclic stability of 97.9% and Coulombic efficiency of 95% over 2000 charge-discharge cycles. In addition, dye-sensitized solar cells are fabricated with CoS counter electrode and the obtained power conversion efficiency of 5.7% is comparable with standard platinum based counter electrode (6.45%). Curie-Weiss plot confirms the transition of paramagnetic nature into ferrimagnetic behavior at 85 K and Pauli-paramagnetic nature at 20 K respectively. Temperature dependent resistivity plot affirms the metallic nature of CoS sample till 20 K and transition to semiconducting nature occurs at <20 K owing to Peierl's transition effect.
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http://dx.doi.org/10.1038/s41598-018-37463-0 | DOI Listing |
Nanomicro Lett
January 2025
State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemistry, Dalian University of Technology, Dalian, 116024, People's Republic of China.
Carbon-based perovskite solar cells (C-PSCs) exhibit notable stability and durability. However, the power conversion efficiency (PCE) is significantly hindered by energy level mismatches, which result in interfacial charge transport barriers at the electrode-related interfaces. Herein, we report a back electrode that utilizes atomically dispersed metallic cobalt (Co) in carbon nanosheets (Co/CN) to adjust the interfacial energy levels.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Guangdong University of Technology, school of chemical engineering and light industry, Panyu, Guangzhou University City Outer Ring Road No. 100, 510006, Gaungzhou, CHINA.
Weak dipole interactions between highly symmetric H2O molecules and SO42- species are the root cause of unstable electric double layer (EDL), which triggers the hydrogen evolution reaction and Zn dendrite formation, significantly impeding the commercialization of aqueous zinc-ion batteries. Herein, we designed a microscopic split-phase interface (MSPI) by dual breaking of electron cloud and space structure symmetry to suppress interfacial side reactions and achieve uniform Zn deposition. The structurally asymmetric methylurea (MU) molecules possess both hydrophobic methyl and hydrophilic amino groups, which disrupt the continuity of H-bonding network and the aggregation state of H2O molecules, resulting in peculiar nanoscale core-shell-like clusters.
View Article and Find Full Text PDFChem Soc Rev
January 2025
Centre for Clean Energy Technology, School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, City Campus, Broadway, NSW 2007, Australia.
The battery market is primarily dominated by lithium technology, which faces severe challenges because of the low abundance and high cost of lithium metal. In this regard, multivalent metal-ion batteries (MVIBs) enabled by multivalent metal ions ( Zn, Mg, Ca, Al, ) have received great attention as an alternative to traditional lithium-ion batteries (Li-ion batteries) due to the high abundance and low cost of multivalent metals, high safety and higher volumetric capacities. However, the successful application of these battery chemistries requires careful control over electrode and electrolyte chemistries due to the higher charge density and slower kinetics of multivalent metal ions, structural instability of the electrode materials, and interfacial resistance, This review comprehensively explores the recent advancements in electrode and electrolyte materials as well as separators for MVIBs, highlighting the potential of MVIBs to outperform Li-ion batteries regarding cost, energy density and safety.
View Article and Find Full Text PDFNat Energy
October 2024
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
Microscopy provides a proxy for assessing the operation of perovskite solar cells, yet most works in the literature have focused on bare perovskite thin films, missing charge transport and recombination losses present in full devices. Here we demonstrate a multimodal operando microscopy toolkit to measure and spatially correlate nanoscale charge transport losses, recombination losses and chemical composition. By applying this toolkit to the same scan areas of state-of-the-art, alloyed perovskite cells before and after extended operation, we show that devices with the highest macroscopic performance have the lowest initial performance spatial heterogeneity-a crucial link that is missed in conventional microscopy.
View Article and Find Full Text PDFLangmuir
January 2025
State Key Laboratory of Coordination Chemistry, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
The applications of machine learning (ML) in complex interfacial interactions are hindered by the time-consuming process of manual feature selection and model construction. An automated ML program was implemented with four subsequent steps: data distribution analysis, dimensionality reduction and clustering, feature selection, and model optimization. Without the need of manual intervention, the descriptors of metal charge variance (Δ) and electronegativity of substrate (χ) and metal (δχ) were raised up with good performance in predicting electrochemical reaction energies for both nitrogen reduction reaction (NRR) and CO reduction reaction (CORR) on metal-zeolites and MoS surfaces.
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