Manganese Sulfide Research Articles

MnS nanoparticles embedded uniformly in sulfur/nitrogen-doped porous carbon spheres enhancing lithium-storage performance

Rocksalt-type manganese sulfide (α-MnS) is a promising next generation anode material for lithium-ion batteries, but its practice application is severely impeded by slow conversion kinetics and large volume change. To overcome these drawbacks, α-MnS nanoparticles are uniformly embedded in sulfur/nitrogen-doped porous carbon (S,N-PC) spheres, which are fabricated by absorbing Mn2+ in poly(acrylamide-co-acrylic acid) (P(AM-co-AA)) microgel spheres, in-situ generating MnS@P(AM-co-AA) hybrid spheres, and carbonized at a high temperature. Synergetic effect of nanocrystallization, carbon encapsulation and porous structure endows the MnS@S,N-PC electrode with outstanding electrochemical properties. It can deliver an initial discharge capacity of 822 mAh/g at 0.1C rate in the voltage range of 0.01–3.0 V, accompanying with an initial coulombic efficiency of 82.5 %, and remains 420 mAh/g at 2C rate after 600 cycles. Owing to a large interfacial area between MnS nanoparticles and S,N-PC, pseudocapacitance contributes much more to total capacity during charging/discharging processes. The results suggest that the MnS@S,N-PC spheres can be promisingly developed into high-performance anode materials for lithium-ion batteries.

Control of Bismuth and Manganese Sulfide Inclusions in Free-Cutting Steels of Different Classes

The paper investigates the behavior of bismuth and sulfur in modern free-cutting steels. It is shown that today there are no mutually consistent thermodynamic data for calculating the solubility of bismuth in a multi-component steel system. Based on the processing of data from separate works, mutually consistent dependences of the solubility of bismuth in pure iron, as well as Wagner interaction parameters for calculation for steels, were obtained. An attempt was made to model the formation of bismuth simultaneously with manganese sulfides during solidification based on the Ohnaka segregation model. Comparison with experimental data shows acceptable convergence of calculations and experiments.

Mechanistic scrutinizing the charge storage phenomena of battery-grade Mn-Co-S electrodes

To accelerate the performance of supercapacitors, it is necessary to discover a new class of material with high energy density and redox stability. In this article, we have reported the electrochemical charge storage behavior of binary cobalt manganese sulfides Mn-Co-S (MCS) based binder-free electrodes, which were synthesized thru a facile one-step electrodeposition technique for supercapacitors. We have analyzed the structure and electrochemical properties by Scanning Electron Microscope (SEM), Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS). The charge storage nature of the MCS electrodes were scrutinized by applying Power law and Dunn's model to the experimental data. Extracted b-values and dominated diffusive contribution in total specific capacity reveal that MCS has battery-grade nature with high redox reactions stability and capacity. The outcomes suggested that MCS-based electrodes are an appropriate candidate for enhancing the energy density along with the redox reaction stability of asymmetric supercapacitors.

Features of the structure of steels of various compositions for the manufacture of pipes transporting hydrogen sulfide-containing natural gas

The paper presents the results of studies of the structural features of plate rolled products of low-carbon pipe steels 04KhNDB, 05KhGB and 06GNFB differing in the basic composition and content of microalloying elements. In the production of industrial rolled products for each steel under study, the choice of rolling temperatures was made individually, but in the same way from the point of view of structure formation. The completion of the finishing stage of rolling was carried out in the austenite region near the temperature of the beginning of the phase transformation, the beginning of cooling - from the austenite region, in order to form a homogeneous structure and exclude the formation of structural banding. The steels have a similar microstructure after rolling, but the structure of the axial zone, which is basically the weak point in tests in hydrogen sulfide, is different. The microstructure of steel 04KhNDB is almost uniform in thickness and a slight segregation of manganese has little effect on the hardness of the axial zone. In steels 05KhGB and 06GNFB, segregation of manganese and an increase in the proportion of intermediate transformation products in the axial zone leads to the formation of elongated regions with increased hardness. This is most pronounced in steel 06GNFB, in which cracks were revealed after testing for hydrogen cracking in accordance with the NACE TM0284 method. It has been established that with a homogeneous microstructure in the axial zone of rolled products without areas of increased hardness and in the absence of manganese sulfides in it, large inclusions of titanium and niobium carbonitrides do not adversely affect the resistance to hydrogen cracking.

Manganese-based coordination framework derived manganese sulfide nanoparticles integrated with carbon sheets for application in supercapacitor

Manganese sulfide (MnS) with high specific capacitance and low-cost merits, has been investigated as a potential electroactive material for supercapacitor. However, in practical application, MnS has been suffering from some disadvantageous issues such as insufficient electrical conductivity, serious particle agglomeration as well as huge volume change during continuous charges and discharges, which resulted in a limited specific capacitance, shortened working life and inferior rate performance. Engineering electrode materials with controlled nanostructure and composition is pivotal to improve electrichemical performance of supercapacitors. This paper introduces a facile in situ sulfuration method to fabricate MnS/NSC composite with Mn-hexamethylene tetramine coordination framework as precursor. The results indicated that MnS nanoparticles were highly dispersed and incorporated into nitrogen, sulfur-doped carbon microsheets in MnS/NSC composite. Carbon matrix effectively dispersed and confined the MnS nanoparticles, thus inhibiting aggregation, relieving volume change and retaining structural integrity. Moreover, the 2D conductive carbon matrix reduced the diffusion distance for ions and ensured fast electron delivery. As a result, MnS/NSC electrode delivered a tremendously boosted electrochemical performance for supercapacitor. A large capacitance value about 1881.8F/g was achieved at 1A/g. Even cycling for 3000 loops at 40 A/g, MnS/NSC electrode retained a large capacitance of 404.3F/g. Furthermore, an asymmetric capacitor based on assembly of MnS/NSC composite cathode and activated carbon anode was fabricated. As tested under a current density of 0.1 A/g, it delivered a capacitance of ∼ 110.1F/g and achieved an energy density of 12.4 Wh kg−1 along with a power density of 3.03 kW kg−1. These results demonstrate the potential utilization of MnS/NSC composite as electrodes for energy conversion and storage devices and open up a route for material design for future energy storage devices.

Tellurium Treatment for the Modification of Sulfide Inclusions and Corresponding Industrial Applications in Special Steels: A Review

Tellurium treatment is used to control the morphology of manganese sulfide (MnS) inclusions, reduce the mechanical anisotropy, and improve the machinability of sulfur‐bearing steels, such as free‐cutting steels, super free‐cutting steels, medium‐carbon microalloyed steels, and die steels. The boiling point of tellurium is low, and it is mainly added to steel in the form of fine particles wrapped in a cored wire. In steels, tellurium mainly exists in the form of Mn(S, Te) inclusions or MnTe–MnS composite inclusions. The strength of MnS inclusions is increased through tellurium doping; thus, the aspect ratio of sulfide after hot working is significantly decreased through tellurium treatment. However, the tellurium content in steel should not be too high; otherwise, brittle compounds will form and cause embrittlement, particularly in high‐alloyed steels. The Te/S mass ratio is considered an important factor in tellurium treatment. When the Te/S mass ratio in steel is 0.2, the aspect ratio of the as‐cast sulfide could be controlled within the optimal range. During steelmaking, the yield of Te can be improved by reducing the basicity of the slag and decreasing the time of Te evaporation. Through data‐driven material design, Te treatment technology undergoes broader development.

Corrosion behavior of 316L additively produced by Directed Energy Deposition-Arc

Among all additive manufacturing processes, Directed Energy Deposition-Arc (DED-Arc) shows significantly shorter production times and is particularly suitable for large-volume components of simple to medium complexity. To exploit the full potential of this process, the microstructural, mechanical and corrosion behavior have to be studied. High stickout distances lead to a large offset, which leads to an instable electric arc and thus defects such as lack of fusion. Since corrosion preferentially occurs at such defects, the main objective of this work is to investigate the influence of the stickout distance on the corrosion behavior and microstructure of stainless steel manufactured by DED-Arc.Within the heterogenous structure of the manufactured samples lack of fusion defects were detected. The quantity of such defects was reduced by applying a shorter stickout distance. The corrosion behavior of the additively manufactured specimens was investigated by means of potentiodynamic polarization measurements. The semi-logarithmic current density potential curves showed a similar course and thus similar corrosion resistance like that of the conventionally forged sample. The polarization curve of the reference material shows numerous current peaks, both in the anodic and cathodic regions. This metastable behavior is induced by the presence of manganese sulfides. On the sample surface a local attack by pitting corrosion was identified.

A novel manganese sulfide encapsulating biochar-dispersed zero-valent iron composite for high removal ability of Cr(VI) in water and its mechanism

The nanoscale Zero-Valent Iron (nZVI) is vulnerable to being oxidized and aggregated, which weakens its reactivity and hampers application potential, manganese sulfide (MnS) modification and biochar supporter could provide a new possibility for this issue. In this work, the nZVI was firstly anchored onto bagasse biochar and then vulcanized by MnS (MnS-nZVI@BC) to achieve low aggregation and preeminent removal capacity. The flaky nZVI was uniformly in-situ growth on the biochar's surface to construct flower-like gullies, of which the surface was covered with some amorphous MnS layer. The monolayer chemical reaction dominated the Cr(VI) removal process, and higher temperature benefited the redox reaction to enhance the prominent removal capacity at 405.10 mg/g at 318.15 K, and it was slightly promoted with the coexisting ions. The quadruplicity of redox, electrostatic attraction, adsorption, and co-deposition should be taken into consideration in the mechanism, in which MnS could not only enhance the reducibility from dominant contributor nZVI, but also directly participate in the redox reaction; and Fe(II) also played an important role in the process; whereafter, Fe(III) and Cr(III) form Cr(III)/Fe(III) hydroxide deposited on the surface of the material. Overall, the findings exhibited the great potential of MnS-nZVI@BC in wastewater treatment while also providing an alternative basis to reveal mechanisms involving versatile aspects.

Evaluation of nitrogen content on pitting and repassivation behavior of a high alloy nickel‐reduced austenitic stainless steel

AbstractThe present study deals with the pitting and repassivation behavior of a nickel‐reduced austenitic stainless steel with different nitrogen contents. While nitrogen promoted the resistance to pitting, no significant effect on repassivation was found. The study also aims to address the experimental difficulties in determining repassivation potentials owing to the occurrence of crevice corrosion. Furthermore, the mechanism of the ongoing reactions was investigated, indicating that pitting was initiated in regions where manganese sulfide inclusions were present next to the remaining δ‐ferrite.

Mn-MOF derived manganese sulfide as peroxymonosulfate activator for levofloxacin degradation: An electron-transfer dominated and radical/nonradical coupling process

Recently, transition metal sulfides have attracted much attention due to their better catalytic capacities as peroxymonosulfate (PMS) activator than their metal oxide counterparts. However, the systematic studies on PMS activation using transition metal sulfides are still lacking. In this work, manganese sulfide (MnS) materials were synthesized via a MOFs-derived method and utilized for PMS activation to degrade levofloxacin (LVF) in water for the first time. As expected, MnS exhibited remarkable LVF degradation efficiency by PMS activation, which was distinctly higher than Mn2O3. The results of quenching experiments, electro spin resonance identification and electrochemical tests indicated that electron-transfer progress was the dominant mechanism in α-MnS/PMS system. Meanwhile, the presence of 1O2 and radicals further became the removal of LVF by α-MnS/PMS system into a radical/nonradical coupling process. The superior electrical conductivity of α-MnS than α-Mn2O3 was revealed by DFT calculations, which resulted in the higher catalytic capacity of α-MnS. The result of XPS also indicated the S species in MnS accelerated the recycle of Mn(IV)/Mn(II) and then promoted the generation of radicals. Furthermore, the influence of various environmental conditions on LVF removal and the reusability of α-MnS were also investigated, which demonstrated the high application potential of α-MnS/PMS system. Finally, six possible pathways of LVF oxidation in the system were proposed based on the identified byproducts and their ecotoxicity was evaluated with ECOSAR method. This work promotes the fundamental understanding of PMS activation by α-MnS and provides useful information for practical application of manganese sulfide in water treatment.

A Comparative Study of Protective Film Formation of Additively Manufactured 316L SS and Conventional Wrought 316L SS in Aqueous, Gaseous and Steam Environments

Additively prepared 316L SS using selective laser melting technique has been found to possess better passivation behavior in relation to its wrought counterpart in aqueous media such as chloride solutions, despite having cast structure. This has been attributed to the absence of manganese sulfide inclusions and higher chromium content of the passive film formed on the former. Not much work has been published on the behavior of this alloy in high temperature gaseous and steam environments though it is expected to be employed in such environments. Our studies show that the nature of the oxides formed on oxidation on the additively formed alloy has been found to be notably different from that formed on its wrought alloy counterpart. A talk will bring out the salient differences shown by these two types of alloys and their implication on the protection behavior.

Proficient One-Step Heat-Up Synthesis of Manganese Sulfide Quantum Dots for Solar Cell Applications.

The necessity to develop renewable energy resources that are highly durable and flexible with superior energy density and capacitance ability has attracted considerable interest in the field of solar cell research. Semiconducting compound materials that are easily available, hazard-free and cost-effective are emerging as potential solutions to tackle this challenge. Herein, we present multiple molecular precursors used to grow manganese sulfide nanoparticles through a proficient one-step heat-up approach. For all of the tested samples, the X-ray diffraction peaks correspond to a γ-MnS hexagonal wurtzite structure. UV-Vis spectroscopy yielded absorption wavelengths of 359–420 nm and band-gap energies of 3.78–4.0 eV. Photoluminescence analysis shows characteristics of red and blue shift from 451–602 nm. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) reveal a narrow size distribution with nanosticks and large contact areas, which are critical for improved catalytic performance. The current study provides an improved pathway to a well-grown and uniform nanocrystal structure for applications in energy devices.

A flexible cathode of nickel-manganese sulfide microparticles on carbon cloth for aqueous asymmetric supercapacitors with high comprehensive performance

Herein, a flexible cathode with high performance, which consists of nickel (Ni)-manganese (Mn) sulfide (S) microparticles on activated carbon cloth (ACC), i.e., Ni–Mn–S/ACC, prepared by one-step electrodeposition of the Ni–Mn based compound and subsequent sulfurization is reported. The optimized Ni–Mn–S/ACC cathode has a high capacitance (∼12789.6 mF cm−2 at 1.0 mA cm−2), good rate performance (∼3352 mF cm−2 up to 60.0 mA cm−2) and cycling behavior (∼81.7% retention of the initial capacitance after 5000 cycles at 50 mA cm−2). An aqueous asymmetric supercapacitor assembled using the cathode of Ni–Mn–S/ACC, the anode of activated carbon on carbon cloth and the electrolyte of 6.0 M potassium hydroxide delivers a desirable energy density of ∼0.789 mWh cm−2 at 0.850 mW cm−2 and good cycling performance of ∼82.8% capacitance retention after 18,000 cycles at 25.0 mA cm−2 with the Coulombic efficiency around 100%.

A non-aqueous nickel–manganese sulfide on rGO wrapped Ni-foam as a supercapacitor advanced electrode material

A non-aqueous nickel–manganese sulfide on rGO wrapped Ni-foam as a supercapacitor advanced electrode material

Cobalt–manganese sulfide hybridized Fe-doped 1T-Vanadium disulfide 3D-Hierarchical core-shell nanorods for extreme low potential overall water-splitting

The cobalt manganese sulfide [CoMnS2] hybridized with Fe-doped (1T)-phase vanadium disulfide [VS2] 3D-hierarchical core-shell nanorods arrays electrocatalyst on nickel foam [NF] (CoMnS2@1T-Fe-VS2@NF) has been fabricated for overall water-splitting in the present study. The CoMnS2@1T-Fe-VS2@NF performs superior activities through the interface engineering between 1D cobalt manganese sulfide (CoMnS2) core and Fe-doped metallic (1T)-phase VS2 (1T-Fe-VS2) shell due to the modulation of surface electronic structure, hence, leading to enhancement of the intrinsic conductivity of the whole core-shell structure. The CoMnS2@1T-Fe-VS2@NF having plentiful heterointerfaces, requires a low overpotential of 89 mV to deliver 10 mA/cm2- for hydrogen evolution reaction (HER) and 260 mV to deliver 20 mA/cm2- for oxygen evolution reaction (OER). The CoMnS2@1T-Fe-VS2@NF (+, -) alkaline electrolyzer requires a low cell voltage of 1.51 V at 10 mA/cm2- for overall water splitting and demonstrates outstanding long-term stability during hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) over 30 h of continuous operation. The outstanding performance of CoMnS2@1T-Fe-VS2@NF can be ascribed to the synergistic catalysis of CoMnS2 core with the activated basal planes and edge sites of 1T-Fe-VS2 shell.

Sulfur defects engineering enables high-performance manganese sulfide anode

Poor intrinsic electrical and ionic conductivity has severely impeded the applications of high-capacity sulfide anodes such as α-MnS. Defects engineering has been proven effective to alleviate the dilemma. While α-MnS also undergoes huge volume variation upon cycling. We here report the synergistic effect of pomegranate composite structure and S detect for MnS anode to address these issues. Sufficient S vacancies are implanted onto fine MnS nanoparticles (NPs) confined in N, S-codoped mesoporous carbon host, which can improve the electric conductivity and modulate electronic structure to enhance Li+ conversion redox, suggested by theoretical calculations. Continuous carbon networks act as electron highways, and physical barrier that confines MnS NPs size and defines the formation of solid electrolyte interphase, where abundant voids are retained to tolerate volume evolution. Thereby optimal MnS/C composite anode achieves notably improved cycling performance (460 mAh g−1 maintained after 1500 cycles at 1.6 A g−1). Operando optical observation validates the advantages of such a pomegranate nanostructure through maintaining structural integrity.

Application of fractal theory to study morphology of manganese sulfide inclusion in resulfurized free-cutting steels

Application of fractal theory to study morphology of manganese sulfide inclusion in resulfurized free-cutting steels

Effect of TiN on Sulfide Morphology of Non-Quenched and Tempered Steel

In this paper, non-quenched and tempered steel was selected to observe sulfide inclusions in as-cast and forged steel with different Ti and N contents, and analyzed the influence of TiN on the precipitation, morphology, distribution and composition of MnS. The precipitation of MnS and TiN in liquid-phase, solid–liquid two-phase region and solid phase was comparatively analyzed from a thermodynamic perspective, and the effect of the thermodynamic precipitation sequence on composite sulfide was explored. It was found that the change in Ti content had little effect on the morphology of sulfide in its as-cast state, and the composite sulfide was more spindle-like in the forged state. The increase in Ti and N content will increase the content of composite sulfide containing TiN in the steel, especially the number of MnS with TiN as the nucleation core. The initial precipitation temperature of TiN is higher than that of MnS, which provides a thermodynamic explanation for the existence of composite manganese sulfide containing TiN. Titanium treatment provides a new way to improve sulfide morphology.

Evaluation of d-block metal sulfides as electrode materials for battery-supercapacitor energy storage devices

Transition metal sulfides are among the most favored materials for energy storage applications. In this work, an innovative approach to synthesize three distinct samples of manganese sulfide was realized. The three samples were synthesized via sonochemical, hydrothermal and electrodeposition techniques, respectively. At first the elemental and morphological results were obtained for the samples. To evaluate the energy storage capabilities, electrochemical testing was accomplished, employing galvanostatic charging/discharging, cyclic voltammetry, and electro-impedance spectroscopy. A battery-supercapacitor device was assembled by the amalgamation of the superior performing sample with activated carbon in a single device. The device displayed a 127.5 Wh kg−1 energy density and 2550 W kg−1 power density at 3 A g−1, respectively, with a retained capacity of 89.12 % after 1000 cycles. In addition to the electrochemical results, a simulation approach was introduced to extract the capacitive and diffusive contribution of the fabricated device through Dunn's model. The showcased device performance supports the conception of electro-synthesizing materials for energy storage applications.

Effect of tin microalloying on the microstructure of low-carbon free-machining steels

Sn is a well-known grain boundary segregation element that improves the machinability of steel. Sn has been considered as a replacement for Pb in super-free-machining steels. The effect of Sn on the microstructure of the Fe-0.05C-0.03Si-1.28Mn-0.36S-0.05P base composition containing 0.0002 (without addition), 0.062, 0.12, and 0.18 Sn (wt.%) low-carbon free-machining steels was investigated though thermodynamic calculations, optical microscopy, scanning electron microscopy, transmission electron microscopy, electron probe microanalysis, and high-temperature laser scanning confocal microscopy. The microstructure of the free-machining steels was composed of α-ferrite, pearlite, and manganese sulfide. Sn significantly decreased the pearlite content of the steels. Most of the Sn was dissolved in the matrix, and the remainder was dissolved in manganese sulfide. No FeSn intermetallic compound precipitation was observed through transmission electron microscopy, but a significant strengthening effect was observed in α-ferrite. Sn had little effect on the solidification behavior or sulfide precipitation behavior of the steels when its content was lower than 0.2 wt.%. Similar to Al and Si, Sn is a ferrite-stabilizing element that expands both the δ-ferrite and α-ferrite phase regions, promotes α-ferrite formation, and inhibits carbide precipitation. Sn segregates at the interface, decreasing the interfacial energy and promoting the Widmanstätten ferrite phase transformation. A much lower cooling rate than that of Sn-free free-machining steels should be adopted to restrain the formation of Widmanstätten ferrite after hot rolling. Sn addition greatly improved the machinability of the experimental steels.