The poor crystallinity and unstable crystal structure of tungsten disulfide(WS2)limit its application in practice.In this paper,a molten salt electrolysis method is proposed to intercalate metal ions into the interlay...The poor crystallinity and unstable crystal structure of tungsten disulfide(WS2)limit its application in practice.In this paper,a molten salt electrolysis method is proposed to intercalate metal ions into the interlayers of layered WS2 to obtain few-layer sheetlike structures.The effect of the molten salt system,applied constant current and electrolysis duration on the exfoliation degree of WS2 bulk has been investigated.The results show that the products electrolyzed in molten LiCl-NaCl-KCl and NaClKCl salts under 25 mA were more transparent and thinner flakes sheets due to the uniform intercalation of Li^+and Na^+with smaller size.The exfoliated WS_(2)was used as an anode material for sodium-ion batteries with a potential of 0.01-2.50 V.In comparison,the WS_(2)-NaCl-25 mA electrode displays a high reversible capacity of 373 mAh·g^(-1)at0.1 A·g^(-1)after cycling for 100 cycles at the same time showing great rate and cycle performance.It also presents a high capacitive ratio of 90.65%at 1.0 mV·s^(-1).The molten salt electrolysis provides a new perspective on the exfoliation of layered material,while demonstrating the great potential of WS2 as an anode material for sodium-ion battery.展开更多
The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledim...The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.展开更多
Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale appli...Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale applications.Here,hollow silicon/germanium(H-SiGe)nanospheres with a binary-active component and heterogeneous structure combined with porous carbon(pC)reinforcing are synthesized as lithium-ion battery anodes.Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny volume expansion,high ion/electron conductivity,and stable electrode interface.Theoretical calculations confirm that through the replacement of Si using Ge with rational component control,the diffusion energy barrier of lithium will be reduced and lithium storage ability can be improved because of the slight charge polarization.Benefiting from these unique merits,the H-SiGe/pC anodes display a high initial specific capacity of 2922.2 mA h g^(-1)at 0.1 A g^(-1),superior rate capability(59.4%capacity retention from 0.5 to 8 A g^(-1)),and excellent cycling stability(81%retention after 700 cycles at 5 A g^(-1)at 1.0–1.2 mg cm^(-2)).An outstanding stability is preserved even at a high loading of 3.2 mg cm^(-2)with an improved reversible capacity of 429.1 mA h g^(-1)after 500 cycles at 4 A g^(-1).Furthermore,the full-cell with the prelithiated H-SiGe/pC anode and LiFePO4cathode exhibits an impressive capacity performance.展开更多
Silicon has a large impact on the energy supply and economy in the modern world. In industry, high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further ref...Silicon has a large impact on the energy supply and economy in the modern world. In industry, high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further refined by a modified Siemens method. This process suffers from the disadvantages of high cost and contaminant release and emission. As an alternative, the molten salt electrolysis approach, particularly the FFC Cambridge Process(FFC: Fray-Farthing-Chen), could realize high purity silicon products with morphology-controllable nanostructures at low or mild temperatures(generally 650–900 ℃). In this article, we review the development, reaction mechanisms, and electrolysis conditions of silicon production by the FFC Cambridge Process. Applications of the silicon products from electrolysis in molten salts are also discussed in terms of energy applications, including using them as the photovoltaic element in solar cells and as the charge storage phase in the negative electrode(negatrode) of lithium ion batteries.展开更多
Thermal batteries are unique direct current(DC) electrical power sources with long shelf live, high reliability and higher power density than classical alkaline batteries. This paper gives a brief overview into the wo...Thermal batteries are unique direct current(DC) electrical power sources with long shelf live, high reliability and higher power density than classical alkaline batteries. This paper gives a brief overview into the working principle of thermal batteries and reviews the properties of zirconium/barium chromate(Zr/BaCrO4) pyrolant previously used as first fire and iron/potassium perchlorate(Fe/KClO4) pyrolant(Heat), commonly applied as heating pellet in thermal batteries and its hazard properties. The review gives 64 references to the public domain. CAS-Nos. Zr: [7440-67-7], BaCrO4: [10294-40-3], Fe: [7439-89-6], KClO4: [7778-74-7], Viton: [9011-17-0].CAS-Nos. Zr: [7440-67-7], BaCrO4: [10294-40-3], Fe: [7439-89-6], KClO4: [7778-74-7], Viton: [9011-17-0].展开更多
The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, ...The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.展开更多
A pyrotechnical battery is successfully prepared, including an anode and cathode having pyrotechnic charges with Zr, CuO and asbestos. The anode and cathode are separated by a separator formed from LiF, ZrO2, and a fi...A pyrotechnical battery is successfully prepared, including an anode and cathode having pyrotechnic charges with Zr, CuO and asbestos. The anode and cathode are separated by a separator formed from LiF, ZrO2, and a fibrous sponge. A digital phosphor oscilloscope （DPO） is used to analyze discharge characterization of the pyrotechnical battery. Then the properties of the electrode materials are characterized by EDS, SEM and a temperature recorder, respectively. The discharge mechanism and safety characteristic are also discussed. The results indicate that the combustion temperature of electrode materials is determined as 1 500.6 ℃ according to thermometry analysis （the case temperature of the battery is lower）. The combustion product is identified as ZrO2, Cu2O and Cu by X-ray diffraction （XRD）. When the diaphragm is completely melted, Li＋ migration and an embedded-based conductive process are formed. Then an electromotive force will immediately reach to the maximum. The discharge performance of the pyrotechnical battery then takes on stability. The electromotive force is up to 2.29 V, and that discharge time continues for more than 18 s. The current density in the small area （less than 2.88 Acm-2） is most effective. The conversion efficiency of electric energy is 96%. The pyrotechnical battery is very safe for the production and use processes.展开更多
以金属锂作为负极的固态锂‐氧气电池由于超高的比能量和宽操作温度而成为当前国际研究的热点,但是金属锂的高反应活性使基于金属锂负极的固态锂金属电池难以在高温下稳定地工作.用高离子导体的三元碱金属锂盐作为金属锂(Li)负极与固态...以金属锂作为负极的固态锂‐氧气电池由于超高的比能量和宽操作温度而成为当前国际研究的热点,但是金属锂的高反应活性使基于金属锂负极的固态锂金属电池难以在高温下稳定地工作.用高离子导体的三元碱金属锂盐作为金属锂(Li)负极与固态电解质(Li_(1.5)Al_(0.5)Ge_(1.5)P_(3)O_(12),LAGP)之间的人工界面层,改善Li/LAGP之间的界面接触,降低其界面阻抗,提高界面稳定性.基于此制备的固态锂‐氧气电池在150℃可以释放出1.58 m Ah·cm^(12)的容量,对应库伦效率接近100%,在定容0.1 m Ah·cm^(12)时,可稳定循环40周期.为高温电池的研究和开发提供了有效的途径.展开更多
Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated c...Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated chemical vapor deposition or pulse laser deposition in a limited scale.In this work,we have succes s fully pre pared a-Si spheres(~200 nm) by reducing the TiO2-coated silica spheres with Al powders in the molten salts at 300℃.The coated TiO2 layer acts as a protective layer for structural maintenance during the reduction and a precursor for doping.The doped Ti element may suppress the crystal growth of Si to facilitate the formation of a-Si.The observation with in-situ transmission electron microscopy(TEM) further reveals that lithiation kinetics of the synthesized a-Si is controlled by the interfacial reaction.The Li^(+) diffusivity in a-Si determined from the observation is in the order of 10^(-14) cm^(2)/s.The anode of a-Si spheres together with crystalline Si nanoparticles exhibits excellent electrochemical performance,delivering a reversible capacity of 1604 mAh/g at 4 A/g and a capacity retention of 78,3%after 500 cycles.The low temperature reduction process reported in this study provides a low-cost method to fabricate a-Si nanostructures as high-capacity durable anode materials.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities(Nos.N2025034 and N2025035)Xingliao Project(No.XLYC1807042)the Program of the Ministry of Education of China for Introducing Talents of Discipline to Universities(No.B16009)。
文摘The poor crystallinity and unstable crystal structure of tungsten disulfide(WS2)limit its application in practice.In this paper,a molten salt electrolysis method is proposed to intercalate metal ions into the interlayers of layered WS2 to obtain few-layer sheetlike structures.The effect of the molten salt system,applied constant current and electrolysis duration on the exfoliation degree of WS2 bulk has been investigated.The results show that the products electrolyzed in molten LiCl-NaCl-KCl and NaClKCl salts under 25 mA were more transparent and thinner flakes sheets due to the uniform intercalation of Li^+and Na^+with smaller size.The exfoliated WS_(2)was used as an anode material for sodium-ion batteries with a potential of 0.01-2.50 V.In comparison,the WS_(2)-NaCl-25 mA electrode displays a high reversible capacity of 373 mAh·g^(-1)at0.1 A·g^(-1)after cycling for 100 cycles at the same time showing great rate and cycle performance.It also presents a high capacitive ratio of 90.65%at 1.0 mV·s^(-1).The molten salt electrolysis provides a new perspective on the exfoliation of layered material,while demonstrating the great potential of WS2 as an anode material for sodium-ion battery.
基金supported by the National Natural Science Foundation of China(No.51872090)Natural Science Foundation of Hebei Province(No.E2019209433,E2022209158)Colleges and Universities in Hebei Province Science and Technology Research Project(No.JZX2024026).
文摘The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.
基金supported by the National Natural Science Foundation of China programs(52007110,22078179,21901146)the Natural Science Foundation of Shandong Province(ZR2020QB048)the Taishan Scholar Foundation(tsqn201812063)。
文摘Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale applications.Here,hollow silicon/germanium(H-SiGe)nanospheres with a binary-active component and heterogeneous structure combined with porous carbon(pC)reinforcing are synthesized as lithium-ion battery anodes.Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny volume expansion,high ion/electron conductivity,and stable electrode interface.Theoretical calculations confirm that through the replacement of Si using Ge with rational component control,the diffusion energy barrier of lithium will be reduced and lithium storage ability can be improved because of the slight charge polarization.Benefiting from these unique merits,the H-SiGe/pC anodes display a high initial specific capacity of 2922.2 mA h g^(-1)at 0.1 A g^(-1),superior rate capability(59.4%capacity retention from 0.5 to 8 A g^(-1)),and excellent cycling stability(81%retention after 700 cycles at 5 A g^(-1)at 1.0–1.2 mg cm^(-2)).An outstanding stability is preserved even at a high loading of 3.2 mg cm^(-2)with an improved reversible capacity of 429.1 mA h g^(-1)after 500 cycles at 4 A g^(-1).Furthermore,the full-cell with the prelithiated H-SiGe/pC anode and LiFePO4cathode exhibits an impressive capacity performance.
基金supported by the National Natural Science Foundation of China (No.51602234)Ningbo Municipal Government (3315 Plan and 2014A35001-1)UK Engineering and Physical Science Research Council (EP/J000582/1, GR/R68078)。
文摘Silicon has a large impact on the energy supply and economy in the modern world. In industry, high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further refined by a modified Siemens method. This process suffers from the disadvantages of high cost and contaminant release and emission. As an alternative, the molten salt electrolysis approach, particularly the FFC Cambridge Process(FFC: Fray-Farthing-Chen), could realize high purity silicon products with morphology-controllable nanostructures at low or mild temperatures(generally 650–900 ℃). In this article, we review the development, reaction mechanisms, and electrolysis conditions of silicon production by the FFC Cambridge Process. Applications of the silicon products from electrolysis in molten salts are also discussed in terms of energy applications, including using them as the photovoltaic element in solar cells and as the charge storage phase in the negative electrode(negatrode) of lithium ion batteries.
文摘Thermal batteries are unique direct current(DC) electrical power sources with long shelf live, high reliability and higher power density than classical alkaline batteries. This paper gives a brief overview into the working principle of thermal batteries and reviews the properties of zirconium/barium chromate(Zr/BaCrO4) pyrolant previously used as first fire and iron/potassium perchlorate(Fe/KClO4) pyrolant(Heat), commonly applied as heating pellet in thermal batteries and its hazard properties. The review gives 64 references to the public domain. CAS-Nos. Zr: [7440-67-7], BaCrO4: [10294-40-3], Fe: [7439-89-6], KClO4: [7778-74-7], Viton: [9011-17-0].CAS-Nos. Zr: [7440-67-7], BaCrO4: [10294-40-3], Fe: [7439-89-6], KClO4: [7778-74-7], Viton: [9011-17-0].
基金Project supported by the Beijing S&T Project,China(Grant No.Z13111000340000)the National Basic Research Program of China(Grant No.2012CB932900)the National Natural Science Foundation of China(Grants Nos.51325206 and 51421002)
文摘The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.
基金Funded by the National Defense Basic Research Sub-programs of China (973 Program)State Key Laboratory of Explosion Science and Technology Foundation (No.2DKT08-5-5)
文摘A pyrotechnical battery is successfully prepared, including an anode and cathode having pyrotechnic charges with Zr, CuO and asbestos. The anode and cathode are separated by a separator formed from LiF, ZrO2, and a fibrous sponge. A digital phosphor oscilloscope （DPO） is used to analyze discharge characterization of the pyrotechnical battery. Then the properties of the electrode materials are characterized by EDS, SEM and a temperature recorder, respectively. The discharge mechanism and safety characteristic are also discussed. The results indicate that the combustion temperature of electrode materials is determined as 1 500.6 ℃ according to thermometry analysis （the case temperature of the battery is lower）. The combustion product is identified as ZrO2, Cu2O and Cu by X-ray diffraction （XRD）. When the diaphragm is completely melted, Li＋ migration and an embedded-based conductive process are formed. Then an electromotive force will immediately reach to the maximum. The discharge performance of the pyrotechnical battery then takes on stability. The electromotive force is up to 2.29 V, and that discharge time continues for more than 18 s. The current density in the small area （less than 2.88 Acm-2） is most effective. The conversion efficiency of electric energy is 96%. The pyrotechnical battery is very safe for the production and use processes.
文摘以金属锂作为负极的固态锂‐氧气电池由于超高的比能量和宽操作温度而成为当前国际研究的热点,但是金属锂的高反应活性使基于金属锂负极的固态锂金属电池难以在高温下稳定地工作.用高离子导体的三元碱金属锂盐作为金属锂(Li)负极与固态电解质(Li_(1.5)Al_(0.5)Ge_(1.5)P_(3)O_(12),LAGP)之间的人工界面层,改善Li/LAGP之间的界面接触,降低其界面阻抗,提高界面稳定性.基于此制备的固态锂‐氧气电池在150℃可以释放出1.58 m Ah·cm^(12)的容量,对应库伦效率接近100%,在定容0.1 m Ah·cm^(12)时,可稳定循环40周期.为高温电池的研究和开发提供了有效的途径.
基金supported by National Key Research and Development Program of China (No.2017YFA0204600)National Natural Science Foundation of China programs (Nos.U1703128,U1503292)the Hong Kong Polytechnic University (No.1-ZVRP)。
文摘Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated chemical vapor deposition or pulse laser deposition in a limited scale.In this work,we have succes s fully pre pared a-Si spheres(~200 nm) by reducing the TiO2-coated silica spheres with Al powders in the molten salts at 300℃.The coated TiO2 layer acts as a protective layer for structural maintenance during the reduction and a precursor for doping.The doped Ti element may suppress the crystal growth of Si to facilitate the formation of a-Si.The observation with in-situ transmission electron microscopy(TEM) further reveals that lithiation kinetics of the synthesized a-Si is controlled by the interfacial reaction.The Li^(+) diffusivity in a-Si determined from the observation is in the order of 10^(-14) cm^(2)/s.The anode of a-Si spheres together with crystalline Si nanoparticles exhibits excellent electrochemical performance,delivering a reversible capacity of 1604 mAh/g at 4 A/g and a capacity retention of 78,3%after 500 cycles.The low temperature reduction process reported in this study provides a low-cost method to fabricate a-Si nanostructures as high-capacity durable anode materials.
