Search2018 Vol. 25, No. 12
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2018, vol. 25, no. 12, pp.
1363-1372.
https://doi.org/10.1007/s12613-018-1690-8
Abstract:
In this study, we obtained information from twenty-one measurement points on the stress magnitudes and orientations of a gold mine in the Ludong area. We used the overcoring technique with an improved hollow inclusion strain gauge and then analyzed the distribution characteristics of the in situ stress field. The results indicate that the stress field is characterized by σH > σh > σv and σH > σv > σh (where σH, σh, and σv are the maximum horizontal, minimum horizontal, and vertical principal stresses, respectively). The regional stress field is dominated by horizontal principal stress. The σH, σh, and σv values show a gradual increasing trend with depth. The σH is predominantly oriented in the NWW-SEE or near-EW direction. We also confirmed the correspondence between the measured stress field and the regional geological structure. In addition, based on the measured stress data, we discuss the implications of the in situ stress with respect to fault activity in the mine area.
In this study, we obtained information from twenty-one measurement points on the stress magnitudes and orientations of a gold mine in the Ludong area. We used the overcoring technique with an improved hollow inclusion strain gauge and then analyzed the distribution characteristics of the in situ stress field. The results indicate that the stress field is characterized by σH > σh > σv and σH > σv > σh (where σH, σh, and σv are the maximum horizontal, minimum horizontal, and vertical principal stresses, respectively). The regional stress field is dominated by horizontal principal stress. The σH, σh, and σv values show a gradual increasing trend with depth. The σH is predominantly oriented in the NWW-SEE or near-EW direction. We also confirmed the correspondence between the measured stress field and the regional geological structure. In addition, based on the measured stress data, we discuss the implications of the in situ stress with respect to fault activity in the mine area.
2018, vol. 25, no. 12, pp.
1373-1379.
https://doi.org/10.1007/s12613-018-1691-7
Abstract:
Willemite is a common component of zinc and lead metallurgical slags that, in the absence of effective utilization methods, cause serious environmental problems. To solve this problem and increase zinc recovery, we proposed a novel extraction method of zinc from willemite by calcified roasting followed by leaching in NH4Cl-NH3·H2O solution. The thermodynamics and phase conversion of Zn2SiO4 to zinc oxide (ZnO) during calcified roasting with CaO were investigated. The mechanism of mineralogical phase conversion and the effects of the CaO-to-Zn2SiO4 mole ratio (n(CaO)/n(Zn2SiO4)), roasting temperature, and the roasting time on zinc-bearing phase conversion were experimentally investigated. The results show that Zn2SiO4 was first converted to Ca2ZnSi2O7 and then to ZnO. The critical step in extracting zinc from willemite is the conversion of Zn2SiO4 to ZnO. The zinc percent leached in the ammonia leaching system rapidly increased because of the gradual complete phase conversion from willemite to ZnO via the calcified roasting process.
Willemite is a common component of zinc and lead metallurgical slags that, in the absence of effective utilization methods, cause serious environmental problems. To solve this problem and increase zinc recovery, we proposed a novel extraction method of zinc from willemite by calcified roasting followed by leaching in NH4Cl-NH3·H2O solution. The thermodynamics and phase conversion of Zn2SiO4 to zinc oxide (ZnO) during calcified roasting with CaO were investigated. The mechanism of mineralogical phase conversion and the effects of the CaO-to-Zn2SiO4 mole ratio (n(CaO)/n(Zn2SiO4)), roasting temperature, and the roasting time on zinc-bearing phase conversion were experimentally investigated. The results show that Zn2SiO4 was first converted to Ca2ZnSi2O7 and then to ZnO. The critical step in extracting zinc from willemite is the conversion of Zn2SiO4 to ZnO. The zinc percent leached in the ammonia leaching system rapidly increased because of the gradual complete phase conversion from willemite to ZnO via the calcified roasting process.
2018, vol. 25, no. 12, pp.
1380-1388.
https://doi.org/10.1007/s12613-018-1692-6
Abstract:
In pyrometallurgical process, Al-and Si-bearing minerals in iron and aluminum ores are easily transformed into sodium aluminosilicates in the presence of Na2O constituents, which alters the leaching behaviors of Al2O3 and SiO2. It was confirmed that sodium aluminosilicates with different phase compositions synthesized at various roasting conditions were effectively digested in the alkaline digestion process. Under the optimum conditions at temperature of 100-120℃, liquid-to-solid ratio (L/S) of 10:2 mL/g, caustic ratio of 4, and Na2O concentration of 240 g/L, the actual and relative digestion ratio of Al2O3 from the synthesized sodium aluminosilicates reached maximums of about 65% and 95%, respectively, while SiO2 was barely leached out. To validate the superior digestion property of sodium aluminosilicate generated via an actual process, the Bayer digestion of an Al2O3-rich material derived from reductive roasting of bauxite and comprising Na1.75Al1.75Si0.25O4 was conducted; the relative digestion ratio of Al2O3 attained 90% at 200℃.
In pyrometallurgical process, Al-and Si-bearing minerals in iron and aluminum ores are easily transformed into sodium aluminosilicates in the presence of Na2O constituents, which alters the leaching behaviors of Al2O3 and SiO2. It was confirmed that sodium aluminosilicates with different phase compositions synthesized at various roasting conditions were effectively digested in the alkaline digestion process. Under the optimum conditions at temperature of 100-120℃, liquid-to-solid ratio (L/S) of 10:2 mL/g, caustic ratio of 4, and Na2O concentration of 240 g/L, the actual and relative digestion ratio of Al2O3 from the synthesized sodium aluminosilicates reached maximums of about 65% and 95%, respectively, while SiO2 was barely leached out. To validate the superior digestion property of sodium aluminosilicate generated via an actual process, the Bayer digestion of an Al2O3-rich material derived from reductive roasting of bauxite and comprising Na1.75Al1.75Si0.25O4 was conducted; the relative digestion ratio of Al2O3 attained 90% at 200℃.
2018, vol. 25, no. 12, pp.
1389-1401.
https://doi.org/10.1007/s12613-018-1693-5
Abstract:
Ti6Al4V powders with three different particle size distributions (0-20, 20-45, and 45-75 μm) were used to evaluate the effect of the particle size distribution on the solid-state sintering and their mechanical properties. The sintering kinetics was determined by dilatometry at temperatures from 900 to 1260℃. The mechanical properties of the sintered samples were evaluated by microhardness and compression tests. The sintering kinetics indicated that the predominant mechanism depends on the relative density irrespective of the particle size used. The mechanical properties of the sintered samples are adversely affected by increasing pore volume fraction. The elastic Young's modulus and yield stress follow a power law function of the relative density. The fracture behavior after compression is linked to the neck size developed during sintering, exhibiting two different mechanisms of failure:interparticle neck breaking and intergranular cracking in samples with relative densities below and above of 90%, respectively. The main conclusion is that relative density is responsible for the kinetics, mechanical properties, and failure behavior of Ti6Al4V powders.
Ti6Al4V powders with three different particle size distributions (0-20, 20-45, and 45-75 μm) were used to evaluate the effect of the particle size distribution on the solid-state sintering and their mechanical properties. The sintering kinetics was determined by dilatometry at temperatures from 900 to 1260℃. The mechanical properties of the sintered samples were evaluated by microhardness and compression tests. The sintering kinetics indicated that the predominant mechanism depends on the relative density irrespective of the particle size used. The mechanical properties of the sintered samples are adversely affected by increasing pore volume fraction. The elastic Young's modulus and yield stress follow a power law function of the relative density. The fracture behavior after compression is linked to the neck size developed during sintering, exhibiting two different mechanisms of failure:interparticle neck breaking and intergranular cracking in samples with relative densities below and above of 90%, respectively. The main conclusion is that relative density is responsible for the kinetics, mechanical properties, and failure behavior of Ti6Al4V powders.
2018, vol. 25, no. 12, pp.
1402-1411.
https://doi.org/10.1007/s12613-018-1694-4
Abstract:
To more comprehensively analyze the effect of CO2 and H2O on the gasification dissolution reaction and deep reaction of coke, the reactions of coke with CO2 and H2O using high temperature gas-solid reaction apparatus over the range of 950-1250℃ were studied, and the thermodynamic and kinetic analyses were also performed. The results show that the average reaction rate of coke with H2O is about 1.3-6.5 times that with CO2 in the experimental temperature range. At the same temperature, the endothermic effect of coke with H2O is less than that with CO2. As the pressure increases, the gasification dissolution reaction of coke shifts to the high-temperature zone. The use of hydrogen-rich fuels is conducive to decreasing the energy consumed inside the blast furnace, and a corresponding high-pressure operation will help to suppress the gasification dissolution reaction of coke and reduce its deterioration. The interfacial chemical reaction is the main rate-limiting step over the experimental temperature range. The activation energies of the reaction of coke with CO2 and H2O are 169.23 kJ·mol-1 and 87.13 kJ·mol-1, respectively. Additionally, water vapor is more likely to diffuse into the coke interior at a lower temperature and thus aggravates the deterioration of coke in the middle upper part of blast furnace.
To more comprehensively analyze the effect of CO2 and H2O on the gasification dissolution reaction and deep reaction of coke, the reactions of coke with CO2 and H2O using high temperature gas-solid reaction apparatus over the range of 950-1250℃ were studied, and the thermodynamic and kinetic analyses were also performed. The results show that the average reaction rate of coke with H2O is about 1.3-6.5 times that with CO2 in the experimental temperature range. At the same temperature, the endothermic effect of coke with H2O is less than that with CO2. As the pressure increases, the gasification dissolution reaction of coke shifts to the high-temperature zone. The use of hydrogen-rich fuels is conducive to decreasing the energy consumed inside the blast furnace, and a corresponding high-pressure operation will help to suppress the gasification dissolution reaction of coke and reduce its deterioration. The interfacial chemical reaction is the main rate-limiting step over the experimental temperature range. The activation energies of the reaction of coke with CO2 and H2O are 169.23 kJ·mol-1 and 87.13 kJ·mol-1, respectively. Additionally, water vapor is more likely to diffuse into the coke interior at a lower temperature and thus aggravates the deterioration of coke in the middle upper part of blast furnace.
2018, vol. 25, no. 12, pp.
1412-1422.
https://doi.org/10.1007/s12613-018-1695-3
Abstract:
The combustion characteristics of blast furnace bag dust (BD) and three kinds of coal-Shenhua (SH) bituminous coal, Pingluo (PL) anthracite, and Yangquan (YQ) anthracite-were obtained via non-isothermal thermogravimetry. The combustion characteristics with different mixing ratios were also investigated. The physical and chemical properties of the four samples were investigated in depth using particle size analysis, Scanning electron microscopy, X-ray diffraction, X-ray fluorescence analysis, and Raman spectroscopy. The results show that the conversion rate of the three kinds of pulverized coals is far greater than that of the BD. The comprehensive combustion characteristics of the three types of pulverized coals rank in the order SH > PL > YQ. With the addition of BD, the characteristic parameters of the combustion reaction of the blend showed an increasing trend. The Coats-Redfern model used in this study fit well with the experimental results. As the BD addition increased from 5wt% to 10wt%, the activation energy of combustion reactions decreased from 68.50 to 66.74 kJ/mol for SH, 118.34 to 110.75 kJ/mol for PL, and 146.80 to 122.80 kJ/mol for YQ. These results also provide theoretical support for the practical application of blast furnace dust for blast furnace injection.
The combustion characteristics of blast furnace bag dust (BD) and three kinds of coal-Shenhua (SH) bituminous coal, Pingluo (PL) anthracite, and Yangquan (YQ) anthracite-were obtained via non-isothermal thermogravimetry. The combustion characteristics with different mixing ratios were also investigated. The physical and chemical properties of the four samples were investigated in depth using particle size analysis, Scanning electron microscopy, X-ray diffraction, X-ray fluorescence analysis, and Raman spectroscopy. The results show that the conversion rate of the three kinds of pulverized coals is far greater than that of the BD. The comprehensive combustion characteristics of the three types of pulverized coals rank in the order SH > PL > YQ. With the addition of BD, the characteristic parameters of the combustion reaction of the blend showed an increasing trend. The Coats-Redfern model used in this study fit well with the experimental results. As the BD addition increased from 5wt% to 10wt%, the activation energy of combustion reactions decreased from 68.50 to 66.74 kJ/mol for SH, 118.34 to 110.75 kJ/mol for PL, and 146.80 to 122.80 kJ/mol for YQ. These results also provide theoretical support for the practical application of blast furnace dust for blast furnace injection.
2018, vol. 25, no. 12, pp.
1423-1430.
https://doi.org/10.1007/s12613-018-1696-2
Abstract:
Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe3O4, and Cr2O3 was studied using the FactSage software, which revealed that SiO2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3B1C3 (t=30 min, C/O=0.4, R=1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity (R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.
Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe3O4, and Cr2O3 was studied using the FactSage software, which revealed that SiO2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3B1C3 (t=30 min, C/O=0.4, R=1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity (R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.
2018, vol. 25, no. 12, pp.
1431-1438.
https://doi.org/10.1007/s12613-018-1697-1
Abstract:
In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500℃, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy (SEM) and X-ray diffractrometry (XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in 3.5wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.
In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500℃, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy (SEM) and X-ray diffractrometry (XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in 3.5wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.
2018, vol. 25, no. 12, pp.
1439-1446.
https://doi.org/10.1007/s12613-018-1698-0
Abstract:
This study investigates a purification process for metallurgical-grade silicon (MG-Si) in which Si is alloyed with tin (Sn) and CaO-SiO2-CaCl2 slag is used to remove boron (B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si-Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1×10-4wt%, 93.9% removal efficiency.
This study investigates a purification process for metallurgical-grade silicon (MG-Si) in which Si is alloyed with tin (Sn) and CaO-SiO2-CaCl2 slag is used to remove boron (B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si-Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1×10-4wt%, 93.9% removal efficiency.
2018, vol. 25, no. 12, pp.
1447-1456.
https://doi.org/10.1007/s12613-018-1699-z
Abstract:
A rapidly air-cooled ladle furnace slag (RA-LFS), which is a type of steelmaking slag discharged from a steel mill, was used to synthesize CaCO3 film. The CaCO3 film with 35 cm2 of surface area was synthesized under atmospheric conditions, and the surface morphology of the CaCO3 films was changed by using additives (CaCl2 and ethylene glycol). Especially, the addition of CaCl2 changed the surface morphology of CaCO3 film with pore and induced new material properties, such as water adsorption. The (012) face of CaCO3 film (calcite) was rapidly decreased by the addition of CaCl2. The major components of RA-LFS were calcium (type of CaO, 53.9wt%) and aluminum (type of Al2O3, 37.9wt%), and the major crystal phases of RA-LFS were C3S, C12A7, and C3A. The calcium extraction efficiency of RA-LFS was significantly increased after the CaCO3 film synthesis. The material properties (hardness and elastic modulus) and the thermal characteristics of the CaCO3 films were analyzed by nano-indentation and thermogravimetry-differential thermal analysis. The synthesized CaCO3 films from RA-LFS and Ca(OH)2 (reagent) showed similarities in terms of their material properties and the decomposition temperature.
A rapidly air-cooled ladle furnace slag (RA-LFS), which is a type of steelmaking slag discharged from a steel mill, was used to synthesize CaCO3 film. The CaCO3 film with 35 cm2 of surface area was synthesized under atmospheric conditions, and the surface morphology of the CaCO3 films was changed by using additives (CaCl2 and ethylene glycol). Especially, the addition of CaCl2 changed the surface morphology of CaCO3 film with pore and induced new material properties, such as water adsorption. The (012) face of CaCO3 film (calcite) was rapidly decreased by the addition of CaCl2. The major components of RA-LFS were calcium (type of CaO, 53.9wt%) and aluminum (type of Al2O3, 37.9wt%), and the major crystal phases of RA-LFS were C3S, C12A7, and C3A. The calcium extraction efficiency of RA-LFS was significantly increased after the CaCO3 film synthesis. The material properties (hardness and elastic modulus) and the thermal characteristics of the CaCO3 films were analyzed by nano-indentation and thermogravimetry-differential thermal analysis. The synthesized CaCO3 films from RA-LFS and Ca(OH)2 (reagent) showed similarities in terms of their material properties and the decomposition temperature.
2018, vol. 25, no. 12, pp.
1457-1464.
https://doi.org/10.1007/s12613-018-1700-x
Abstract:
The aim of this work is to investigate the mechanical properties and microstructures of friction-stir welded (FSWed) St52 structural steel joints. In this study, St52 steel plates with a thickness of 4 mm were butt-welded by friction-stir welding (FSW) using a tungsten carbide tool having a conical pin. The microstructure of the welded zone consists of equiaxed fine ferrite, grain boundary ferrite, Widmanstatten ferrite, and aggregates of ferrite + cementite. The microhardness measurements showed that the hardness of the welded zone was significantly higher than that of the base metal. The FSWed St52 joint exhibited a significant strength overmatching in the weld region and a strength performance similar to or slightly higher than that of the base plate.
The aim of this work is to investigate the mechanical properties and microstructures of friction-stir welded (FSWed) St52 structural steel joints. In this study, St52 steel plates with a thickness of 4 mm were butt-welded by friction-stir welding (FSW) using a tungsten carbide tool having a conical pin. The microstructure of the welded zone consists of equiaxed fine ferrite, grain boundary ferrite, Widmanstatten ferrite, and aggregates of ferrite + cementite. The microhardness measurements showed that the hardness of the welded zone was significantly higher than that of the base metal. The FSWed St52 joint exhibited a significant strength overmatching in the weld region and a strength performance similar to or slightly higher than that of the base plate.
2018, vol. 25, no. 12, pp.
1465-1472.
https://doi.org/10.1007/s12613-018-1701-9
Abstract:
Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25Zn and Al-3Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350℃ for 8 h and then, the alloys were furnace-cooled to 50℃. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise (S/N) ratio analysis, and specific wear rate (SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance (ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) images.
Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25Zn and Al-3Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350℃ for 8 h and then, the alloys were furnace-cooled to 50℃. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise (S/N) ratio analysis, and specific wear rate (SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance (ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) images.
2018, vol. 25, no. 12, pp.
1473-1481.
https://doi.org/10.1007/s12613-018-1702-8
Abstract:
A high-energy-density Li-ion battery with excellent rate capability and long cycle life was fabricated with a Ni-rich layered LiNi0.8Mn0.1Co0.1O2 cathode and SiO-C composite anode. The LiNi0.8Mn0.1Co0.1O2 and SiO-C exhibited excellent electrochemical performance in both half and full cells. Specifically, when integrated into a full cell configuration, a high energy density (280 Wh·kg-1) with excellent rate capability and long cycle life was attained. At 0.5C, the full cell retained 80% of its initial capacity after 200 charge/discharge cycles, and 60% after 600 cycles, indicating robust structural tolerance for the repeated insertion/extraction of Li+ ions. The rate performance showed that, at high rate of 1C and 2C, 96.8% and 93% of the initial capacity were retained, respectively. The results demonstrate strong potential for the development of high energy density Li-ion batteries for practical applications.
A high-energy-density Li-ion battery with excellent rate capability and long cycle life was fabricated with a Ni-rich layered LiNi0.8Mn0.1Co0.1O2 cathode and SiO-C composite anode. The LiNi0.8Mn0.1Co0.1O2 and SiO-C exhibited excellent electrochemical performance in both half and full cells. Specifically, when integrated into a full cell configuration, a high energy density (280 Wh·kg-1) with excellent rate capability and long cycle life was attained. At 0.5C, the full cell retained 80% of its initial capacity after 200 charge/discharge cycles, and 60% after 600 cycles, indicating robust structural tolerance for the repeated insertion/extraction of Li+ ions. The rate performance showed that, at high rate of 1C and 2C, 96.8% and 93% of the initial capacity were retained, respectively. The results demonstrate strong potential for the development of high energy density Li-ion batteries for practical applications.
2018, vol. 25, no. 12, pp.
1482-1492.
https://doi.org/10.1007/s12613-018-1703-7
Abstract:
N-doped carbons were fabricated from zeolite-templated carbon via modification with melamine and mild KOH activation. The N-doping treatment and KOH activation slightly lowered the surface areas of pristine zeolite-templated carbon; nonetheless, N-doped carbons with a lower surface area exhibited much higher capacitance and cycling stability as fabricated into symmetric supercapacitor. Significantly, N-doped carbon obtained at 700℃ showed a capacitance of 45.7 F/g at 0.1 A/g and 42.0 F/g at 10 A/g for the fabricated supercapacitor with 6 M KOH electrolyte, with 92% retention of initial capacitance as current density increased up to 100-fold. This performance was attributed to the dual contribution of electric double-layer capacitance and pseudo-capacitance. The assembled supercapacitor also exhibited excellent cycling stability, with 91% capacitance retention at 10 A/g after 10000 cycles.
N-doped carbons were fabricated from zeolite-templated carbon via modification with melamine and mild KOH activation. The N-doping treatment and KOH activation slightly lowered the surface areas of pristine zeolite-templated carbon; nonetheless, N-doped carbons with a lower surface area exhibited much higher capacitance and cycling stability as fabricated into symmetric supercapacitor. Significantly, N-doped carbon obtained at 700℃ showed a capacitance of 45.7 F/g at 0.1 A/g and 42.0 F/g at 10 A/g for the fabricated supercapacitor with 6 M KOH electrolyte, with 92% retention of initial capacitance as current density increased up to 100-fold. This performance was attributed to the dual contribution of electric double-layer capacitance and pseudo-capacitance. The assembled supercapacitor also exhibited excellent cycling stability, with 91% capacitance retention at 10 A/g after 10000 cycles.
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