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One of the most critical points in the study of LIB-related materials is the extremely high reactivity of Li. In addition to pure Li metal, many Li-containing materials employed in LIBs are highly reactive under ambient conditions. Therefore, they should be stored and treated in an inert environment, such as vacuum chambers and gloveboxes filled with inert gases. In particular, most pristine cathode materials contain Li and are more reactive in air than pristine anode materials are. For instance, various impurities, mostly Li 2 CO 3 , are grown on the surface of pristine NCA (LiNi x Co y Al z O 2 , x + y + z = 1) materials. The precise characterization of these ambient-induced surface impurities is critical for understanding the intrinsic properties of these cathode materials. In this study, we directly image and characterize ambient-induced surface impurities formed on the surface of high-Ni NCA (LiNi 0.8 Co 0.15 Al 0.05 O 2) materials using Kelvin probe force microscopy (KPFM) and scanning spreading resistance microscopy (SSRM). The ambient-induced surface impurities show clearly distinguishable work functions and resistance features compared with the pristine NCA surface. In particular, it is confirmed that the resistance of ambient-induced impurities is significantly higher than that of pristine NCA materials, which can deteriorate the performance of LIB cells. This study provides direction for the fabrication, storage, and processing of LIB cathode materials. • Ambient-induced surface impurities formed on the surface of NCA cathode materials were directly imaged and characterized. • KPFM and SSRM were used for measuring the work function and the resistance of ambient-induced impurities at the nanoscale. • The ambient-induced surface impurities have distinguishable work functions compared with the fresh NCA surface. • The resistance of ambient-induced impurities was significantly higher than that of the fresh NCA surface. [ABSTRACT FROM AUTHOR]

Abstract: Carbothermal process parameters such as powder mixing ratio, temperature, holding time and gas flow rate, which affect on the reasonable growth rate of SiC nanowires were investigated using a mixture of low-purity SiO2 containing iron component and carbon in this study. SiC nanowires are being grown at 1400°C for 2h in an argon flow rate of 2L/min by a vapor–liquid–solid (VLS) process, which produces a very high-purity product with about 60nm and several hundreds of micrometers in diameter and length, respectively. This is attributed to the migration of the iron out of the low-purity SiO2 material as finely divided iron-rich droplets acting in the role of catalyst for the architecture of a SiC one-dimensional structure. The growth rate of SiC nanowires increased with increasing holding time and flow gas rate, inducing the supersaturation degree to become lower. [Copyright &y& Elsevier]

By using a MoI 2 precursor, a one-dimensional linear chain material, Mo 6 S 3 I 6 , was synthesized on a centimeter scale. As MoI 2 can be used to form Mo 6 S 3 I 6 through a gas-phase reaction, a larger amount of single crystals can be synthesized; moreover, these crystals are significantly longer than those synthesized by using Mo, S, and I powder. The synthesized Mo 6 S 3 I 6 exhibited the characteristics of paramagnetic semiconductors with excellent thermal stability and a low bandgap. Furthermore, Mo 6 S 3 I 6 can be separated into long nanometer-scale chains by a solution dispersion process. • First synthesis of cm scale synthesize of vdW 1D material Mo 6 S 3 I 6. • Superior material properties based on high crystallinity. • Atomic level (nm) dispersion for ideal 1D materials. [ABSTRACT FROM AUTHOR]

• Identified polymorphic phase of Ta 2 Ni 3 Se 8 , a three-component one-dimensional chalcogenide material. • New tetragonal phase of the compound (T-Ta 2 Ni 3 Se 8) was proven to have different crystal structure. • Electrical resistance of the new T-Ta 2 Ni 3 Se 8 exhibited a metallic nature. In this study, the polymorphism of Ta 2 Ni 3 Se 8 , a three-component one-dimensional chalcogenide material, was discovered. It was confirmed through X-ray diffraction and transmission electron microscopy analyses that the newly identified tetragonal phase of the compound (T-Ta 2 Ni 3 Se 8) had a different crystal structure from the previously reported orthorhombic phase (O-Ta 2 Ni 3 Se 8). Conventional O-Ta 2 Ni 3 Se 8 is a semiconductor material with ambipolar characteristics, whereas T-Ta 2 Ni 3 Se 8 showed a metallic characteristic in which the electrical resistance slightly increased as the temperature increased. The change in electrical properties due to the variation in lattice isotropy according to the transformation of the crystal system (orthorhombic to tetragonal) is expected to be an important starting point for polymorphism studies of multi-component low-dimensional materials in the future. [ABSTRACT FROM AUTHOR]

• Highly efficient solid-state synthesis of Co 3 O 4 on NMWCNT is reported. • Morphology and structure are investigated by the aid of analytical techniques. • Elevated specific capacitance of 202 F/g at 1 A/g of current density was perceived. • Promising candidate for electrochemical storage. Synthesizing hybrid nanostructures through green protocols continues to attract great attention since it offers atom economy, simple processing, and environmental friendliness; and avoids using harsh chemical reagents. Herein we report the assembly of cobalt oxide on nitrogen-doped multiwalled carbon nanotubes (Co 3 O 4 -NMWCNT) composite synthesized by a green protocol with mechanochemical grinding for supercapacitor applications. The structural and morphological properties of the composites were confirmed by the aid of X-ray diffraction (XRD) studies, Raman spectroscopy, and scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HR-TEM). The synthesized composite material exhibited tube-like morphology with the distribution of Co 3 O 4 nanoparticles. Fabricated Co 3 O 4 -NMWCNT symmetric supercapacitor device was further investigated for its electrochemical properties, thereby leading a high specific capacitance 202 F/g at 1 A/g of current density, with 25 Wh/kg of energy density at 0.9 kW/kg of power density. Therefore, Co 3 O 4 -NMWCNT composite electrodes offer excellent capacitive performance for the energy storage system. [ABSTRACT FROM AUTHOR]

A new of 2D transition metal thiophosphates, Nb 4 P 2 S 21 , was synthesized through a vapor transport reaction. High purity and centimeter-scale large Nb 4 P 2 S 21 crystals were obtained by controlling the growth temperature and stoichiometric ratio between niobium, phosphorus, and sulfur (using excess sulfur condition, Nb: P: S = 4: 2: 23). It was confirmed that large Nb 4 P 2 S 21 crystals could be separated to a nanometer scale through mechanical exfoliation, and the exfoliated Nb 4 P 2 S 21 layer exhibits semiconducting characteristics by measuring the change in electrical conductivity with temperature (increased conductivity with temperature in the range of 93–333 K). Furthermore, the device characteristics for detecting visible ray laser (635 nm) and NO 2 gas molecules were verified. Based on these characteristics, the synthesized 2D material is expected to be a potential candidate for additional 2D materials and in multi-functional sensor devices, including optoelectronics and gas sensing applications. • Synthesis of 2D transition metal thiophosphates Nb 4 P 2 S 21. • Bulk to few nanometer scale separation of Nb 4 P 2 S 21 using mechanical exfoliation. • Multi-functional sensing application in photodetector and gas sensor. [ABSTRACT FROM AUTHOR]

A new type of 1D inorganic material, MoI 3 , which can be separated into individual 1D chains, was synthesized through a vapor transport reaction between molybdenum and iodine. High-purity and centimeter-scale large MoI 3 crystals were obtained by controlling the growth temperature and the stoichiometric ratio between molybdenum and iodine. Their semiconductor characteristics were confirmed by measuring the electrical conductivity as a function of temperature (conductivity increased with increased temperature across the range −70 to 30 °C). Furthermore, it was confirmed that MoI 3 with a 1.27 eV band gap can be separated to a few nanometer scale through mechanical and chemical exfoliation methods and can be used as a photodetector in the near IR (less than 1000 nm)-to-visible light region. This novel 1D material is expected to play an important role in the development of additional low-dimensional materials and in advanced nano-optoelectronic devices. • Synthesis of 1D inorganic material MoI 3 via chemical vapor transport (CVT) method. • Experimental estimation of band gap (∼ 1.27 eV) and application to photodetector. • Bulk to few nanometer scale separations of MoI 3 chains using mechanical and chemical exfoliation. [ABSTRACT FROM AUTHOR]

The two-dimensional (2D) inorganic material Nb 3 I 8 , which can be separated into atomic planes, was synthesized through a vapor transport reaction between niobium and iodine. High-purity and cm scale large Nb 3 I 8 crystals were obtained by controlling the growth temperature (600–700 °C) and the stoichiometric ratio between niobium and iodine (using excess I 2 condition, niobium: iodine = 3:9). The semiconductor characteristics were measured by the change of electrical conductivity with temperature (increased conductivity with temperature in the range of 100 K–300 K), and have a band gap of ∼1 eV (∼1200 nm) through Infrared (IR)-visible light absorption analysis. Based on these characteristics, the device characteristics of detecting IR near 1200 nm region were verified. Besides few-layers of Nb 3 I 8 was acquired by the mechanical exfoliation method, and experimentally observed by atomic force microscopy (AFM). This 2D material is expected to have an important role in developing another 2D materials and in new nano-optoelectronic devices using it. • Synthesis of 2D material Nb 3 I 8 in centimeter scale. • Experimental estimation of band gap of Nb 3 I 8 about (∼1 eV) and application to IR detectors. • Bulk to few-layers separation of Nb 3 I 8 sheet using mechanical exfoliation method. [ABSTRACT FROM AUTHOR]