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Developing low-cost and highly efficient electrochemical materials toward supercapacitor applications is crucial for energy conversion systems. In the present work, dual S, N-doped activated CoFe 2 O 4 @CNTs was successfully synthesized using carbamide and sodium thiosulfate as N and S precursors and CNTs as a substrate via a convenient two-step hydrothermal activation procedure, which presents good performance for supercapacitor. The characterization results indicate that activity S and N atoms can be successfully doped into the framework of CoFe 2 O 4 @CNTs with little impact on the inner morphology and structure. However, the electrode material of N 2 S 1 –CoFe 2 O 4 @CNTs exhibits a superior electrochemical performance with 1053.60 F g−1 at 1 A g−1 in KOH electrolyte due to synergistic effects between spinel-type metal oxides, heteroatoms and sp2 lattice of graphitic carbon. In addition to high energy and power densities, the capacitance retention of charging-discharging reaches 93.15% at a current density of 30 A g−1 after 5000 cycles, exhibiting an outstanding cycle stability and potential lifetime in an alkaline electrolyte. The structure of N x S y -CoFe 2 O 4 @CNTs nanocomposites with excellent electrochemical performances for supercapacitor applications. Image 1 • CoFe 2 O 4 @CNTs and N x S y -CoFe 2 O 4 @CNTs nanocomposites were successfully synthesized. • The electrochemical performances increase with dual heteroatom-doped due to synergistic effects. • The nanocomposites exhibits superior electrochemical performance with 1053.60 F g−1 at 1 A/g. • The capacitance retention reaches 93.15% at 30 A g−1 after 5000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] Nucleation underpins a vast range of phase-transition phenomena in many disciplines. Critical to revealing nucleation thermodynamics and kinetics is the understanding of the nucleus structure at its early stage. Typically, it is assumed that nucleation is a sudden local structural transition from one phase to another. Here, we are able to access fundamental steps in the nucleation from amorphous phase by a combination of molecular simulations and experimental observation. We discover a surprising pathway of semicrystalline nucleation where one of the materials components crystallizes and another remains amorphous between the crystalline planes in the nuclei. The early-stage crystallization nucleus is robustly evidenced to undergo a gradual ordering and densification, originating from the presence of diffuse interfaces, and renders an ultralow interfacial energy that is orders of magnitude lower than those typically used in various formulations of nucleation. Our study provides critical information and insight for the early stages of nucleation that determine how crystallization is initiated and benefits controllable synthesis of materials. [ABSTRACT FROM AUTHOR]

The demand for low-cost and high-performance energy storage supercapacitors is continuously promoting as a result of the rapid development of portable electric vehicles and electronic devices. Here, a high-performance MnCo alloy nanoparticles decorated boron-doped carbon nanotubes (MnCo–B/CNTs) electrode was obtained by a facile heteroatom hydrothermal and subsequent liquid-phase reduction methods, which yields improved performance for supercapacitor. In this process, boron doping led to extra oxygen graft into carbon surface, leading to the improved durability and wettability of the fabricated carbon-based electrodes, which presented both increased capacitances and rate capability due to electrolyte ion penetration and interactions with carbon surface. In addition, boron doping led to smaller size and higher dispersion of MnCo nanoparticles, facilitating more metallic alloy and new electroactive sites formation and promoting supercapacitive activity, which was attributed to increased MnCo alloy nucleation rate with boron-doped, electron donation from boron to alloy, and extra chemisorption sites. The constructed electrode exhibited all-round performance improvements of specific capacitance (1175 F g−1 at 0.5 A g−1) and capacitance retention (94.48% at a current density of 20 A g−1 after 5000 cycles), providing a novel insight for designing high performance supercapacitors. The structure of MnCo-B/CNTs nanocomposites with excellent electrochemical performances in supercapacitor for the potential applications. Image 1 • B/CNTs and MnCo–B/CNTs nanocomposites were successfully synthesized. • The nanocomposites display perfect electrochemical performances with the increase of content of boron-doped and MnCo NPs decorated. • The (MnCo) 2 –B 2 /CNTs composites exhibit superior electrochemical performance with 1175 F g−1 at 0.5 A g−1. • The BET specific surface area and capacitance retention reach 1133.5 m2 g−1 and 93.15% at 20 A g−1 after 5000 cycles. [ABSTRACT FROM AUTHOR]

Here, we sprang up a novel approach to synthesize molybdenum disulfide nanoparticles coated by hexagonal boron nitride via high-temperature sintering technique under floating ammonia gas at 900 °C for 3 h MoS 2 -BN nanocomposites have significant thermal stability with an oxidation temperature of 715 °C, indicating that its antioxidant performance increased by 217% compared with the pure MoS 2 nanospheres. Additionally, the strong red PL signal of MoS 2 -BN characterized by Steady state transient fluorescence spectrometer appears at ~678 nm at room temperature, its strength has reached 3.14 × 106 CPS, while the original MoS 2 nanospheres shows almost no characteristics, demonstrating that the nanocomposites have excellent luminescent properties. Therefore, the improved properties of molybdenum disulfide materials encapsulated by hexagonal boron nitride (h-BN) expand the applications of MoS 2 nanospheres in high temperature and optoelectronic devices, which could pave way for the h-BN encapsulated transition metal dichalcogenides (TMDCs). [ABSTRACT FROM AUTHOR]

• The Ni/Co@C 5 M displays cross-linking structure with fast ions transport. • The Ni/Co@C 5 M shows the excellent specific capacitance of 1827.5 Fg−1 at 1 A g−1. • The assembled asymmetric supercapacitor has a superior energy density of 78.4 Wh kg−1 at 699.3 W kg−1. • The energy density is better than others related ASC devices reported in previous work. Supercapacitors attract tremendous research attention due to the cost-effectiveness, high power capacity and environment-friendly in the field of energy storage. In this work, Ni 3 S 2 thin-layer nanosheets coupled with Co 9 S 8 nanoparticles anchored on 3D cross-linking composite structure 5 mLCNT@MXene matrix (Ni/Co@C 5 M) was successfully synthesized via two-step hydrothermal and subsequent annealing treatment, possessing excellent electrochemical performance in terms of high rate capability, superior reversible capacity and outstanding durability. The electrode materials have distinct 3D cross-linking composite structure characteristics, which can significantly boost capacitive storage performance due to the introduction of CNT cross-linking conductive bridges and sulfides. Meanwhile, CNT can also prevent re-stacking of MXene layers and improve the electrical conductivity. As expected, the specific capacitance of Ni/Co@C 5 M electrode is 1827.5 F g−1 at 1 A g−1, which retains 88.57% after 10,000 cycles at a high current density of 30 A g−1 in cycling stability. Notably, an asymmetric supercapacitor (Ni/Co@C 5 M as the negative electrode and AC as the positive electrode, Ni/Co@C 5 M // AC) has exceptionally high energy density up to 78.4 Wh kg−1 at a power density of 699.3 W kg−1 and long capacitance retention of 86.67% at 20 A g−1 for 10,000 cycles. The designed Ni/Co@C 5 M // AC asymmetric supercapacitor in this work holds a promising future for the upgrading new high-performance energy storage device. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel 3D hierarchical network porous CNS@Ag 0.5 @Co-180-10/GNPs hetero-nanostructure hybrid was successfully synthesized using an assistance of nickel foam as a precursor structure-controlling template. • The mass ratio of the second metal, hybridized temperature and activated time were verified to be the extremely sensitive parameters, affecting the electrochemical activity of CNS@Ag 0.5 @Co precursor. • The as-prepared CNS@Ag 0.5 @Co-180-10/GNPs sample exhibits large specific surface area, suitable wider mesopores and narrow micropores porosity, and unique morphology. • Due to the synergistic effect contribution of multi-compositional features, the CNS@Ag 0.5 @Co-180-10/GNPs displays an excellent electrochemical performance with 657.6 F g−1 for specific capacitance at 1 A g−1 and 97.11% for capacitance retention at a current density of 15 A g−1 after 5000 cycles. The increasing demands for green sustainable energy have motivated much interest and attention in energy conversion systems. In this work, 3D hierarchical network porous CNS@Ag 0.5 @Co-180-10/GNPs hetero-nanostructure hybrid was successfully designed and fabricated via a multistep transformation approach of liquid-phase reduction procedure and subsequent hydrothermal activation pathway, through using a facile heteroatoms synergistic-doping cobalt-based AgCo hybrid and precursor assisted-templating strategy. Here, the chemical compositions, structure parameters and electrochemical performances of C, N, S-tri-doped Ag@Co composites precursor can be simply tuned by adjusting the requirement of Ag content in alloys, hybridization temperature and activation time. It was found that the typical CNS@Ag 0.5 @Co-180-10/GNPs material possessed a molar ratio of 0.5:1 of Ag and Co, hybridized at 180 °C and activated for 10 h is endowed with large specific surface area (1370 m2g−1), suitable porosity (wider mesopores and narrow micropores), unique morphology (porous 3D hierarchical network structure) and outstanding electrochemical performance (657.6 F g−1 at 1 A g−1 for specific capacitance, 97.11% at a current density of 15 A g−1 after 5000 cycles for capacitance retention), providing a new insight to design a promising electrode materials for high-performance supercapacitors. Image, graphical abstract [ABSTRACT FROM AUTHOR]