Two multifunctional metal–organic frameworks (MOFs) with the same coordination mode, Co(L)(H2O) n ·2nH2O defined as “Co(L) MOF” and Cd(L)(H2O) n ·2nH2O defined as “Cd(L) MOF” (L = ...5-aminoisophthalic acid) have been fabricated via a simple and versatile scalable solvothermal approach at 85 °C for 24 h. The relationship between the structure of the electrode materials (especially the coordination water and different metal ions) and the electrochemical properties of MOFs have been investigated for the first time. And then the possible electrochemical mechanisms of the electrodes have been studied and proposed. In addition, MOFs/RGO hybrid materials were prepared via ball milling, which demonstrated better electrochemical performances than those of individual Co(L) MOF and Cd(L) MOF. For example, when Co(L) MOF/RGO was applied as anode for sodium ion batteries (SIBs), it retained 206 mA h g–1 after 330 cycles at 500 mA g–1 and 1185 mA h g–1 could be obtained after 50 cycles at 100 mA g–1 for lithium-ion batteries (LIBs). The high-discharge capacity, excellent cyclic stability combined with the facile synthesis procedure enable Co(L) MOF- and Cd(L) MOF-based materials to be prospective anode materials for SIBs and LIBs.
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IJS, KILJ, NUK, PNG, UL, UM
Tin phosphide (Sn4P3) nanoparticles with different sizes are synthesized via a facile solvothermal method at 180 °C for 10 h. The as-prepared Sn4P3 nanoparticles have an average size of about 15 nm. ...Meanwhile, their size could be easily controlled by the solvent ratio. The long cycle stability and rate performance of the as-obtained Sn4P3 nanoparticles have been tested as an anode material for lithium ion batteries for the first time. Electrochemical measurements show that the Sn4P3 nanoparticles with a smallest size give the best cycling and rate performances. They deliver a discharge capacity of 612 mAh g−1 after 10 cycles and could still maintain 442 mAh g−1 after 320 cycles at the current density of 100 mA g−1 within voltage limit of 0.01–3.0 V. Even after 200 cycles at a current density of 200 mA g−1, the specific capacity still could be remained at 315 mAh g−1. The improved electrochemical performances of Sn4P3 electrode might be largely attributed to their small-size. Furthermore, the as-prepared Sn4P3 nanoparticles have also been tested as an anode material for Na-ion batteries, this Sn4P3 anode can deliver a reversible capacity of 305 mAh g−1 after 10 cycles at the current density of 50 mA g−1.
The long cycle stability and TEM image of as-obtained Sn4P3 nanoparticles. Display omitted
•Sn4P3 nanoparticles were synthesized via a simple solvothermal route at 180 °C for 10 h.•The solvent ratio play crucial roles on the size modulation of Sn4P3 nanoparticles.•The long cycle stability of Sn4P3 nanoparticles is firstly reported in this study.•It is the first time to report the rate performance of Sn4P3 nanoparticles.•The Sn4P3 nanoparticles have also been applied as an anode material for Na-ion batteries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Three-dimensional (3D) hierarchical nanostructures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to the synergistic combination of the advantages ...of both nanostructures and microstructures. In this study, the honeycomb-like mesoporous NiO microspheres as promising cathode materials for supercapacitors have been achieved using a hydrothermal reaction, followed by an annealing process. The electrochemical tests demonstrate the highest specific capacitance of 1250 F g–1 at 1 A g–1. Even at 5 A g–1, a specific capacitance of 945 F g–1 with 88.4% retention after 3500 cycles was obtained. In addition, the 3D porous graphene (reduced graphene oxide, rGO) has been prepared as an anode material for supercapacitors, which displays a good capacitance performance of 302 F g–1 at 1 A g–1. An asymmetric supercapacitor has been successfully fabricated based on the honeycomb-like NiO and rGO. The asymmetric supercapacitor achieves a remarkable performance with a specific capacitance of 74.4 F g–1, an energy density of 23.25 Wh kg–1, and a power density of 9.3 kW kg–1, which is able to light up a light-emitting diode.
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IJS, KILJ, NUK, PNG, UL, UM
The proof-of-principle of an unusual fused γ-Mo
O
chain as an inorganic ligand is presented for the first time. By sharing two Mo-O edges, the γ-Mo
O
subunits are propagated into a one-dimensional ...(1D) zig-zag chain, which acts as a purely inorganic ligand binding octahedral Co(ii) centers into a two-dimensional (2D) CoMo
O
sheet. This material exhibits high initial reversible specific capacity and stable reversible capacity when applied as an anode for lithium-ion batteries (LIBs).
Redox-active organic polymers are promising cathode electrodes owing to the advantages of open and flexible frame-works, renewability and environmental friendliness. Sodium salt of poly (2, ...5-dihydroxy-p-benzoquinonyl sulfide)/RGO (Na2PDHBQS/RGO) composite has been fabricated via a convenient route and applied as a high performance and stable cathode for sodium ion batteries. The Na2PDHBQS/RGO was investigated in ether-based electrolyte, which demonstrated better electrochemical performances (228, 214, 203, 193, 172 and 147 mAh g−1 at 0.1, 0.2, 0.4, 0.8, 2 and 4C, respectively) than that in traditional ester-based ones. The high specific capacity, excellent cycle stability and reversibility of Na2PDHBQS/RGO may be attributed to the special porous structure, enhanced electronic conductivity by the introduction of RGO and fast sodium ion and electron diffusion rate in ether-based electrolyte. In addition, the Na2PDHBQS/RGO cathode has been assembled with disodium terephthalate (Na2TP) anode to compose a full cell for the first time, which presents an initial reversible capacity of 210 mAh g−1 at 0.1C.
Novel porous Na2PDHBQS/RGO composite has been prepared and investigated as a cathode for sodium ion batteries in ether-based electrolyte with excellent cycle stability and rate performances. The full cell of Na2PDHBQS/RGO-Na2TP delivers an initial reversible capacity of 210 mAh g−1, indicating its promising potential for practical applications. Display omitted
•Poly (2, 5-dihydroxy- p-benzoquinonyl sulfide)/RGO was used for SIBs.•The polymer/RGO composite showed higher capacity than individual polymer.•The polymer demonstrated better stability than the sodium salt of the monomer.•Fast ion and electrons diffusion rates was obtained in ether-based electrolyte.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Cu
3
P/reduced graphene oxide (Cu
3
P/RGO) nanocomposite was successfully synthesized by a facile one-pot method as an advanced anode material for high-performance lithium-ion batteries. Cu
...3
P nanostructures with a polyhedral shape with the mean diameter (80–100 nm) were homogeneously anchored on the surface of RGO. The flexible RGO sheets acted as elastic buffering layer which not only reduced the volume change, but also prevented the aggregation of Cu
3
P nanostructures, the cracking and crumbing of electrodes. On the other hand, the presence of Cu
3
P nanostructures could also avoid the agglomeration of RGO sheets and retain their highly active surface area. Therefore, as an advanced anode material for high-performance lithium-ion batteries, the as-prepared Cu
3
P/RGO exhibited high capacity of 756.15 mAhg
−1
at the current density 500 mAg
−1
after 80 cycles, superior cyclic stability and good rate capability.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Tungsten is a high-value resource with a wide range of applications. The tungsten metal is produced via ammonium paratungstate, which is a multi-stage process including leaching, conversion, ...precipitation, calcination, and reduction. A short process to produce tungsten metal from the electrolysis of molten sodium tungstate has been demonstrated. However, sodium tungstate cannot be directly produced from wolframite in the conventional hydrometallurgical process. There was no information reported in the literature on producing sodium tungstate directly from tungsten concentrates. The present study proposed a simple and low-cost process to produce sodium tungstate by high-temperature processing of wolframite. The mixtures of wolframite, sodium carbonate, and silica were melted in air between 1100 and 1300 °C. High-density sodium tungstate was easily separated from the immiscible slag, which contained all impurities from wolframite, flux, excess sodium oxide, and dissolved tungsten oxide. The slag was further water leached to recover sodium tungstate in the solution. Effects of Na2CO3/Ore and SiO2/Ore ratios, temperature, and reaction time on the recovery of tungstate and the purity of sodium tungstate were systematically studied. Sodium tungstate containing over 78% WO3 was produced in the smelting process, which is suitable for the electrolysis process. The experimental results will provide a theoretical basis for the direct production of sodium tungstate from wolframite. The compositions of the WO3-containing slags and sodium tungstate reported in the present study fill the knowledge gap of the tungsten-containing thermodynamic database. Further studies to use complex and low-grade tungsten concentrates to produce sodium tungstate are underway.
The cycling performances with different current density: (a) 100mAg−1 (b) 200mAg−1.
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•Mn-doped Sn4P3 particles were synthesized via a facile ultrasonic assisted method.•The Mn dopant ...content play crucial roles on structure stability of Sn-Mn-P structure.•The Mn-doped Sn4P3 has a potential application as anode material for Li-ion batteries.
This paper reports the synthesis of various molar concentrations of manganese (Mn)-doped Sn4P3 nanoparticles and and their efficient use as anode materials for rechargeable lithium-ion batteries (LIBs). The nanoparticles were synthesized via a novel and facile ultrasonic assisted hydrothermal method and characterized in detail by various analytical techniques. The XRD, SEM, and TEM results showed that Mn ion was successfully substituted on the Sn4P3 layered structure without any structure changes. The long cycle stability of the as-prepared Mn-doped Sn4P3 nanoparticles have been tested as an anode material for lithium ion batteries at the different current density. By detailed experimental results exhibited that the Mn dopant content crucially determines the electrochemical performances of Sn4P3 nanoparticles. Electrochemical measurements show that the Sn4P3 nanoparticles with 0.10 mol% molar concentration of Mn dopant give the best cycling performances. They deliver a discharge capacity of 488mAhg−1 after 150 cycles at the current density of 100mAg−1. Even after 150 cycles at a current density of 200mAg−1, the specific capacity still could be remained at 420mAhg−1. Further increasing the current density to 1000mAg−1, it could still maintain 255mAhg−1 after 200 cycles. It is confirmed that Mn substitution in the Sn-Mn-P structure is an important pole to improve the structure stability and electrochemical properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
High yields of CoFe204, NiFe204 and CdFe204 hierarchical porous ball-in-ball hollow spheres have been achieved using hydrothermal synthesis followed by calcination. The mechanism of formation is ...shown to involve an in situ carbonaceous-template process. Hierarchical porous CoFe2O4 hollow spheres with different numbers of shells can be obtained by altering the synthesis conditions. The electrochemical properties of the resulting CoFe2O4 electrodes have been compared, using different binders. The as-obtained CoFe2O4 and NiFe2O4 have relatively high reversible discharge capacity and good rate retention performance which make them promising materials for use as anode materials in lithium ion batteries.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Tungsten is one of the strategic metals produced from tungsten ores through sodium tungstate. The hydrometallurgical process is a common technology for extracting sodium tungstate from high-grade ...tungsten concentrates. The grade of tungsten ore is decreasing, and the mineral processing to produce a high-grade concentrate suitable for the hydrometallurgical process is becoming more difficult. It is desirable to develop a new technology to effectively recover tungsten from the complex low-grade tungsten ores. A fundamental study on the pyrometallurgical processing of wolframite was carried out through thermodynamic calculations and high-temperature experiments. The wolframite was reacted with Na2CO3 and SiO2 at 1050–1200 °C and then leached with water to obtain a sodium tungstate solution as a feed for the traditional process of APT (Ammonium paratungstate). The factors affecting the extraction rate of tungsten from wolframite were investigated in air and neutral atmosphere. The extraction rate of tungsten was found to increase with increasing Na2O content and decrease with increasing SiO2 addition and temperature. The extraction rate in argon was higher than that in air for wolframite.
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