The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,...The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton(3DIO FCSe-QDs@NC)is elaborately designed for both sulfur cathode and Li metal anode.The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble Li PSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors.Simultaneously,the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites.Taking advantage of these merits,the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability(a low decay rate of 0.014%over 2,000 cycles at 2C).Remarkably,a promising areal capacity of 8.41 mAh cm^(-2)can be achieved at the sulfur loading up to 8.50 mg cm^(-2)with an ultra-low electrolyte/sulfur ratio of 4.1μL mg^(-1).This work paves the bi-serve host design from systematic experimental and theoretical analysis,which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.展开更多
As promising anode candidates for potassium-ion batteries(PIBs),antimony sulfide(Sb_(2)S_(3))possesses high specific capacity but suffers from massive volume expansion and sluggish kinetics due to the large K^(+)inser...As promising anode candidates for potassium-ion batteries(PIBs),antimony sulfide(Sb_(2)S_(3))possesses high specific capacity but suffers from massive volume expansion and sluggish kinetics due to the large K^(+)insertion,resulting in inferior cycling and rate performance.To address these challenges,a yolk-shell structured Sb_(2)S_(3)confined in N,S co-doped hollow carbon nanorod(YS-Sb_(2)S_(3)@NSC)working as a viable anode for PIBs is proposed.As directly verified by in situ transmission electron microscopy(TEM),the buffer space between the Sb_(2)S_(3)core and thin carbon shell can effectively accommodate the large expansion stress of Sb_(2)S_(3)without cracking the shell and the carbon shell can accelerate electron transport and K^(+)diffusion,which plays a significant role in reinforcing the structural stability and facilitating charge transfer.As a result,the YS-Sb_(2)S_(3)@NSC electrode delivers a high reversible K^(+)storage capacity of 594.58 m A h g^(-1)at 0.1 A g^(-1)and a long cycle life with a slight capacity degradation(0.01%per cycle)for 2000 cycles at 1 A g^(-1)while maintaining outstanding rate capability.Importantly,utilizing in in situ/ex situ microscopic and spectroscopic characterizations,the origins of performance enhancement and K^(+)storage mechanism of Sb_(2)S_(3)were clearly elucidated.This work provides valuable insights into the rational design of high-performance and durable transition metal sulfides-based anodes for PIBs.展开更多
Amorphous carbon materials hold great potential for practical use in potassium-ion batteries(PIBs)due to their abundant resources,low cost and high structural stability.However,given the challenge of sluggish potassia...Amorphous carbon materials hold great potential for practical use in potassium-ion batteries(PIBs)due to their abundant resources,low cost and high structural stability.However,given the challenge of sluggish potassiation kinetics,the rate performance of amorphous carbon is severely hindered.Herein,amorphous carbon compounded with graphitic domains(HG-CNTs)was proposed as an advanced anode for PIBs.As directly verified by in situ transmission electron microscopy(TEM),the graphitic domains guarantee fast K-ions transport in the carbon composite at a high current density,while the amorphous carbon shells ensure the structural integrity during potassiation,thus boosting its fast and durable K^(+)storage.As a PlB anode,the HG-CNTs electrode exhibits not only a super-stable long-term cyclability(191.6 mAh g^(-1)at 1 A g^(-1)with almost no capacity decay over 3000 cycles),but also an outstanding rate performance(184.5 mAh g^(-1)at 2 A g^(-1)).Ex situ Raman and TEM results further suggest that the highly reversible structure of HG-CNTs is responsible for its superior electrochemical stability.This work provides helpful insights into the development of carbonaceous electrodes with both high rate capability and long cycle life for PIBs.展开更多
Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity...Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity and high-rate capability.Herein,we demonstrate that TiO_(2)nanosheets(meso-TiO_(2)-NSs)with densely packed mesoporous are capable of fast pseudocapacitance-dominated sodium-ion storage,as well as high volumetric and gravimetric capacities.Through compressing treatment,the compaction density of meso-TiO_(2)-NSs is up to~1.6g/cm^(2),combined with high surface area and high porosity with mesopore channels for rapid Na+diffusion.The compacted meso-TiO_(2)-NSs electrodes achieve high pseudocapacitance(93.6%of total charge at 1mV/s),high-rate capability(up to 10 A/g),and long-term cycling stability(10,000 cycles).More importantly,the space-efficiently packed structure enables high volumetric capacity.The thick-film meso-TiO_(2)-NSs anode with the mass loading of 10mg/cm^(2)delivers a gravimetric capacity of 165 mAh/g and a volumetric capacity of 223 mAh/cm^(3)at 5 mA/cm^(2),much higher than those of commercial hard carbon anode(80mAh/g and 86mAh/cm^(3)).This work highlights a pathway for designing a dense nanostructure that enables fast charge kinetics for high-density sodium-ion storage.展开更多
Vanadium nitride(VN)electrode displays high-rate,pseudocapacitive responses in aqueous electrolytes,however,it remains largely unclear in nonaqueous,Na+-based electrolytes.The traditional view supposes a conversion-ty...Vanadium nitride(VN)electrode displays high-rate,pseudocapacitive responses in aqueous electrolytes,however,it remains largely unclear in nonaqueous,Na+-based electrolytes.The traditional view supposes a conversion-type mechanism for Na+storage in VN anodes but does not explain the phenomena of their size-dependent specific capacities and underlying causes of pseudocapacitive charge storage behaviors.Herein,we insightfully reveal the VN anode exhibits a surface-redox pseudocapacitive mechanism in nonaqueous,Na+-based electrolytes,as demonstrated by kinetics analysis,experimental observations,and first-principles calculations.Through ex situ X-ray photoelectron spectroscopy and semiquantitative analyses,the Na+storage is characterized by redox reactions occurring with the V5+/V4+to V3+at the surface of VN particles,which is different from the well-known conversion reaction mechanism.The pseudocapacitive performance is enhanced through nanoarchitecture design via oxidized vanadium states at the surface.The optimized VN-10 nm anode delivers a sodium-ion storage capability of 106 mAh g−1 at the high specific current of 20 A g−1,and excellent cycling performance of 5000 cycles with negligible capacity losses.This work demonstrates the emerging opportunities of utilizing pseudocapacitive charge storage for realizing high-rate sodium-ion storage applications.展开更多
In recent years, tungsten disulfide(WS_(2)) and tungsten selenide(WSe_(2)) have emerged as favorable electrode materials because of their high theoretical capacity, large interlayer spacing, and high chemical activity...In recent years, tungsten disulfide(WS_(2)) and tungsten selenide(WSe_(2)) have emerged as favorable electrode materials because of their high theoretical capacity, large interlayer spacing, and high chemical activity;nevertheless, they have relatively low electronic conductivity and undergo large volume expansion during cycling, which greatly hinder them in practical applications. These drawbacks are addressed by combining a superior type of carbon material, graphene, with WS_(2) and WSe_(2) to form a WS_(2)/WSe_(2)@graphene nanocomposites.These materials have received considerable attention in electro-chemical energy storage applications such as lithium-ion batteries(LIBs), sodium-ion batteries(SIBs),and supercapacitors. Considering the rapidly growing research enthusiasm on this topic over the past several years, here the recent progress of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications is summarized. Furthermore, various methods for the synthesis of WS_(2)/WSe_(2)@graphene nanocomposites are reported and the relationships among these methods, nano/microstructures, and electrochemical performance are systematically summarized and discussed. In addition, the challenges and prospects for the future study and application of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications are proposed.展开更多
Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demon...Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.展开更多
Mini-LED backlights,combining color conversion materials with blue mini-LED chips,promise traditional liquid crystal displays(LCDs)with higher luminance,better contrast,and a wider color gamut.However,as color convers...Mini-LED backlights,combining color conversion materials with blue mini-LED chips,promise traditional liquid crystal displays(LCDs)with higher luminance,better contrast,and a wider color gamut.However,as color conversion materials,quantum dots(QDs)are toxic and unstable,whereas commercially available inorganic phosphors are too big in size to combine with small mini-LED chips and also have strong size-dependence of quantum efficiency(QE)and reliability.In this work,we prepare fine-grained Sr_(2)Si_(5)N_(8):Eu^(2+)-based red phosphors with high efficiency and stability by treating commercially available phosphors with ball milling,centrifuging,and acid washing.The particle size of phosphors can be easily controlled by milling speed,and the phosphors with a size varying from 3.5 to 0.7 mm are thus obtained.The samples remain the same QE as the original ones(~80%)even when their particle size is reduced to 3.2-3.5 mm,because they contain fewer surface suspension bond defects.More importantly,SrBaSi_(5)N_(8):Eu^(2+)phosphors show a size-independent thermal quenching behavior and a zero thermal degradation.We demonstrate that red-emitting mini-LEDs can be fabricated by combining the SrBaSi_(5)N_(8):Eu^(2+)red phosphor(3.5 mm in size)with blue mini-LED chips,which show a high external quantum efficiency(EQE)of above 31%and a super-high luminance of 34.3 Mnits.It indicates that fine and high efficiency phosphors can be obtained by the proposed method in this work,and they have great potentials for use in mini-LED displays.展开更多
Discovery of new phosphors with desired properties is of great significance for developing high optical quality solid-state lighting.The single-particle-diagnosis approach is an effective way to search novel phosphors...Discovery of new phosphors with desired properties is of great significance for developing high optical quality solid-state lighting.The single-particle-diagnosis approach is an effective way to search novel phosphors by analyzing tiny single crystals screened from the fired powder mixtures.In this work,a broadband orange-emitting phosphor of Sr(3)Si_(8)O_(4)N_(10):Eu^(2+)for solid state lighting was discovered by this method.The new oxonitridosilicate crystallizes in the monoclinic space group of P2_(1)/n(No.14)with cell parameters of a=4.8185 A,b=24.2303 A,c=10.5611 A,β=90.616°,and Z=4.The crystal structure of SrsSigO4Nio was determined from the single-crystal X-ray diffraction(XRD)data of a single crystal,which is made up of a three-dimensional framework consisting of vertex-sharing SiN_(4)and SiN_(3)O tetrahedra.Sr^(2+)ions occupy five crystallographic sites and have coordination numbers between 6 and 8 with one ordered Sr and other four disordered Sr atoms.The multiple Sr sites lead to a broadband emission centered at 565-600 nm and a bandwidth of 128-138 nm.The internal and external quantum efficiencies(IQE/EQE)of the title phosphor are 48.6%and 29.1%under 450 nm excitation,respectively.To improve the accuracy and speed of distinguishing phosphor particles in fired powder mixtures,a microscopic imaging spectroscopy is developed and demonstrated to modify the single-particle-diagnosis method.展开更多
A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating con...A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating consisted of MgCO3,Mg(OH)2 and MgO,and provided satisfactory protection in 3.5 wt%NaCl with a corrosion rate of 0.07 mm y−1 in 72 h.However,after that period,the corrosion rate of the specimen increased due to the damage of the coating.The failure of the coating was strongly related to the second phase particles(e.g.Zr particles)or impurities in the matrix.The AP+H coating is supposed to be used as a primer coating for Mg applications in kitchen ware,biomedical areas or industry.展开更多
CONSPECTUS:Laser diodes(LDs),free of“efficiency droop”,can bear a superhigh power density.Laser-driven white light sources(blue LD+laser phosphors),which promise super brightness and high directionality,have emerged...CONSPECTUS:Laser diodes(LDs),free of“efficiency droop”,can bear a superhigh power density.Laser-driven white light sources(blue LD+laser phosphors),which promise super brightness and high directionality,have emerged for various applications,including lighting,displays,communications,and endoscopy.Laser phosphors are critical components of this technology,which determine the luminous efficacy,luminance,and color quality of the device.However,most phosphors suffer from serious luminance saturation when excited by a high-powerdensity blue laser.展开更多
基金financial support from the National Natural Science Foundation of China(Grant Nos.51871188 and 51931006)the Fundamental Research Funds for the Central Universities of China(Xiamen University:Nos.20720200068,20720190007 and 20720220074)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2021A1515010139)Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(HRTP-[2022]-22)the“Double-First Class”Foundation of Materials Intelligent Manufacturing Discipline of Xiamen University。
文摘The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton(3DIO FCSe-QDs@NC)is elaborately designed for both sulfur cathode and Li metal anode.The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble Li PSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors.Simultaneously,the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites.Taking advantage of these merits,the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability(a low decay rate of 0.014%over 2,000 cycles at 2C).Remarkably,a promising areal capacity of 8.41 mAh cm^(-2)can be achieved at the sulfur loading up to 8.50 mg cm^(-2)with an ultra-low electrolyte/sulfur ratio of 4.1μL mg^(-1).This work paves the bi-serve host design from systematic experimental and theoretical analysis,which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.
基金supported by the National Natural Science Foundation of China(Grants Nos.52072323 and 52122211)the"Double-First Class"Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen Universitythe State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(Grant No.LAPS22005)。
文摘As promising anode candidates for potassium-ion batteries(PIBs),antimony sulfide(Sb_(2)S_(3))possesses high specific capacity but suffers from massive volume expansion and sluggish kinetics due to the large K^(+)insertion,resulting in inferior cycling and rate performance.To address these challenges,a yolk-shell structured Sb_(2)S_(3)confined in N,S co-doped hollow carbon nanorod(YS-Sb_(2)S_(3)@NSC)working as a viable anode for PIBs is proposed.As directly verified by in situ transmission electron microscopy(TEM),the buffer space between the Sb_(2)S_(3)core and thin carbon shell can effectively accommodate the large expansion stress of Sb_(2)S_(3)without cracking the shell and the carbon shell can accelerate electron transport and K^(+)diffusion,which plays a significant role in reinforcing the structural stability and facilitating charge transfer.As a result,the YS-Sb_(2)S_(3)@NSC electrode delivers a high reversible K^(+)storage capacity of 594.58 m A h g^(-1)at 0.1 A g^(-1)and a long cycle life with a slight capacity degradation(0.01%per cycle)for 2000 cycles at 1 A g^(-1)while maintaining outstanding rate capability.Importantly,utilizing in in situ/ex situ microscopic and spectroscopic characterizations,the origins of performance enhancement and K^(+)storage mechanism of Sb_(2)S_(3)were clearly elucidated.This work provides valuable insights into the rational design of high-performance and durable transition metal sulfides-based anodes for PIBs.
基金financially supported by the National Natural Science Foundation of China(52172240)the Fundamental Research Funds for the Central Universities(20720200075)the National Program for Thousand Young Talents of China,and the“Double-First Class”Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University。
文摘Amorphous carbon materials hold great potential for practical use in potassium-ion batteries(PIBs)due to their abundant resources,low cost and high structural stability.However,given the challenge of sluggish potassiation kinetics,the rate performance of amorphous carbon is severely hindered.Herein,amorphous carbon compounded with graphitic domains(HG-CNTs)was proposed as an advanced anode for PIBs.As directly verified by in situ transmission electron microscopy(TEM),the graphitic domains guarantee fast K-ions transport in the carbon composite at a high current density,while the amorphous carbon shells ensure the structural integrity during potassiation,thus boosting its fast and durable K^(+)storage.As a PlB anode,the HG-CNTs electrode exhibits not only a super-stable long-term cyclability(191.6 mAh g^(-1)at 1 A g^(-1)with almost no capacity decay over 3000 cycles),but also an outstanding rate performance(184.5 mAh g^(-1)at 2 A g^(-1)).Ex situ Raman and TEM results further suggest that the highly reversible structure of HG-CNTs is responsible for its superior electrochemical stability.This work provides helpful insights into the development of carbonaceous electrodes with both high rate capability and long cycle life for PIBs.
基金support from the National Natural Science Foundation of China(Nos.22005256,22179-113),the Natural Science Foundation of Fujian Province of China(No.2020J01034)Fundamental Research Funds for the Central Universities(Nos.20720210045,2072-0210084)+4 种基金Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)(No.HRTP-2022-19)Kun Lan acknowledges the support from the National Natural Science Foundation of China(No.22205118)the“Junma"Program of Inner Mongolia University(No.21300-5223715)the Grassland Talent Program of Inner Mongolia Autonomous Region of China.Haobin Wu acknowledges the support the Zhejiang Provincial Natural Science Foundation(No.LR21E020003)the National Natural Science Foundation of China(No.22005266).
文摘Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity and high-rate capability.Herein,we demonstrate that TiO_(2)nanosheets(meso-TiO_(2)-NSs)with densely packed mesoporous are capable of fast pseudocapacitance-dominated sodium-ion storage,as well as high volumetric and gravimetric capacities.Through compressing treatment,the compaction density of meso-TiO_(2)-NSs is up to~1.6g/cm^(2),combined with high surface area and high porosity with mesopore channels for rapid Na+diffusion.The compacted meso-TiO_(2)-NSs electrodes achieve high pseudocapacitance(93.6%of total charge at 1mV/s),high-rate capability(up to 10 A/g),and long-term cycling stability(10,000 cycles).More importantly,the space-efficiently packed structure enables high volumetric capacity.The thick-film meso-TiO_(2)-NSs anode with the mass loading of 10mg/cm^(2)delivers a gravimetric capacity of 165 mAh/g and a volumetric capacity of 223 mAh/cm^(3)at 5 mA/cm^(2),much higher than those of commercial hard carbon anode(80mAh/g and 86mAh/cm^(3)).This work highlights a pathway for designing a dense nanostructure that enables fast charge kinetics for high-density sodium-ion storage.
基金National Natural Science Foundation of China,Grant/Award Numbers:22005256,22179113Fundamental Research Funds for the Central Universities,Grant/Award Number:20720210045Natural Science Foundation of Fujian Province of China,Grant/Award Number:2020J01034。
文摘Vanadium nitride(VN)electrode displays high-rate,pseudocapacitive responses in aqueous electrolytes,however,it remains largely unclear in nonaqueous,Na+-based electrolytes.The traditional view supposes a conversion-type mechanism for Na+storage in VN anodes but does not explain the phenomena of their size-dependent specific capacities and underlying causes of pseudocapacitive charge storage behaviors.Herein,we insightfully reveal the VN anode exhibits a surface-redox pseudocapacitive mechanism in nonaqueous,Na+-based electrolytes,as demonstrated by kinetics analysis,experimental observations,and first-principles calculations.Through ex situ X-ray photoelectron spectroscopy and semiquantitative analyses,the Na+storage is characterized by redox reactions occurring with the V5+/V4+to V3+at the surface of VN particles,which is different from the well-known conversion reaction mechanism.The pseudocapacitive performance is enhanced through nanoarchitecture design via oxidized vanadium states at the surface.The optimized VN-10 nm anode delivers a sodium-ion storage capability of 106 mAh g−1 at the high specific current of 20 A g−1,and excellent cycling performance of 5000 cycles with negligible capacity losses.This work demonstrates the emerging opportunities of utilizing pseudocapacitive charge storage for realizing high-rate sodium-ion storage applications.
基金financially supported by the National Key Research and Development Program of China (No.2020YFB1713500)the Chinese 02 Special Fund (No.2017ZX02408003)+5 种基金Open Fund of State Key Laboratory of Advanced Refractories (No.SKLAR202210)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials &Henan Key Laboratory of High-temperature Structural and Functional MaterialsHenan University of Science and Technology (No.HKDNM2019013)the Foundation of Department of Science and Technology of Henan Province (No.212102210219)the Student Research Training Plan of Henan University of Science and Technology (No.2021035)the Undergraduate Innovation and Entrepreneurship Training Program of Henan Province (No.S202110464005)。
文摘In recent years, tungsten disulfide(WS_(2)) and tungsten selenide(WSe_(2)) have emerged as favorable electrode materials because of their high theoretical capacity, large interlayer spacing, and high chemical activity;nevertheless, they have relatively low electronic conductivity and undergo large volume expansion during cycling, which greatly hinder them in practical applications. These drawbacks are addressed by combining a superior type of carbon material, graphene, with WS_(2) and WSe_(2) to form a WS_(2)/WSe_(2)@graphene nanocomposites.These materials have received considerable attention in electro-chemical energy storage applications such as lithium-ion batteries(LIBs), sodium-ion batteries(SIBs),and supercapacitors. Considering the rapidly growing research enthusiasm on this topic over the past several years, here the recent progress of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications is summarized. Furthermore, various methods for the synthesis of WS_(2)/WSe_(2)@graphene nanocomposites are reported and the relationships among these methods, nano/microstructures, and electrochemical performance are systematically summarized and discussed. In addition, the challenges and prospects for the future study and application of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications are proposed.
基金the National Key Research and Development Program of China(No.2020YFB1713500)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials&Henan Key Laboratory of High-temperature Structural and Functional Materials,Henan University of Science and Technology(No.HKDNM2019013)+1 种基金the Student Research Training Plan of Henan University of Science and Technology(Nos.2021026 and 2021035)the Undergraduate Innovation and Entrepreneurship Training Program of Henan Province(No.S202110464005).
文摘Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.
基金This work is supported by the National Natural Science Foundation of China(Nos.51832005 and 52172157)the Fundamental Research Funds for the Central Universities(No.20720200075)Fujian Provincial Science and Technology Project(Nos.2020I0002 and 2021J01042).
文摘Mini-LED backlights,combining color conversion materials with blue mini-LED chips,promise traditional liquid crystal displays(LCDs)with higher luminance,better contrast,and a wider color gamut.However,as color conversion materials,quantum dots(QDs)are toxic and unstable,whereas commercially available inorganic phosphors are too big in size to combine with small mini-LED chips and also have strong size-dependence of quantum efficiency(QE)and reliability.In this work,we prepare fine-grained Sr_(2)Si_(5)N_(8):Eu^(2+)-based red phosphors with high efficiency and stability by treating commercially available phosphors with ball milling,centrifuging,and acid washing.The particle size of phosphors can be easily controlled by milling speed,and the phosphors with a size varying from 3.5 to 0.7 mm are thus obtained.The samples remain the same QE as the original ones(~80%)even when their particle size is reduced to 3.2-3.5 mm,because they contain fewer surface suspension bond defects.More importantly,SrBaSi_(5)N_(8):Eu^(2+)phosphors show a size-independent thermal quenching behavior and a zero thermal degradation.We demonstrate that red-emitting mini-LEDs can be fabricated by combining the SrBaSi_(5)N_(8):Eu^(2+)red phosphor(3.5 mm in size)with blue mini-LED chips,which show a high external quantum efficiency(EQE)of above 31%and a super-high luminance of 34.3 Mnits.It indicates that fine and high efficiency phosphors can be obtained by the proposed method in this work,and they have great potentials for use in mini-LED displays.
基金supported by the National Key R&D Program of China(No.2022YFE0108800)the National Natural Science Foundation of China(Nos.51832005,51802274,62075203,and U2005213)Foreign Coorperation Project of Fujian Provincial Science and Technology Plan(No.202010002).
文摘Discovery of new phosphors with desired properties is of great significance for developing high optical quality solid-state lighting.The single-particle-diagnosis approach is an effective way to search novel phosphors by analyzing tiny single crystals screened from the fired powder mixtures.In this work,a broadband orange-emitting phosphor of Sr(3)Si_(8)O_(4)N_(10):Eu^(2+)for solid state lighting was discovered by this method.The new oxonitridosilicate crystallizes in the monoclinic space group of P2_(1)/n(No.14)with cell parameters of a=4.8185 A,b=24.2303 A,c=10.5611 A,β=90.616°,and Z=4.The crystal structure of SrsSigO4Nio was determined from the single-crystal X-ray diffraction(XRD)data of a single crystal,which is made up of a three-dimensional framework consisting of vertex-sharing SiN_(4)and SiN_(3)O tetrahedra.Sr^(2+)ions occupy five crystallographic sites and have coordination numbers between 6 and 8 with one ordered Sr and other four disordered Sr atoms.The multiple Sr sites lead to a broadband emission centered at 565-600 nm and a bandwidth of 128-138 nm.The internal and external quantum efficiencies(IQE/EQE)of the title phosphor are 48.6%and 29.1%under 450 nm excitation,respectively.To improve the accuracy and speed of distinguishing phosphor particles in fired powder mixtures,a microscopic imaging spectroscopy is developed and demonstrated to modify the single-particle-diagnosis method.
基金supported by the National Natural Science Foundation of China(No.51801168).
文摘A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating consisted of MgCO3,Mg(OH)2 and MgO,and provided satisfactory protection in 3.5 wt%NaCl with a corrosion rate of 0.07 mm y−1 in 72 h.However,after that period,the corrosion rate of the specimen increased due to the damage of the coating.The failure of the coating was strongly related to the second phase particles(e.g.Zr particles)or impurities in the matrix.The AP+H coating is supposed to be used as a primer coating for Mg applications in kitchen ware,biomedical areas or industry.
基金supported by the National Natural Science Foundation of China(Nos.51832005,52272165,and U2005213)the Fundamental Research Funds for the Central Universities(Nos.20720220087 and 20720220066)the Fujian Provincial Science and Technology Project(2020I0002).
文摘CONSPECTUS:Laser diodes(LDs),free of“efficiency droop”,can bear a superhigh power density.Laser-driven white light sources(blue LD+laser phosphors),which promise super brightness and high directionality,have emerged for various applications,including lighting,displays,communications,and endoscopy.Laser phosphors are critical components of this technology,which determine the luminous efficacy,luminance,and color quality of the device.However,most phosphors suffer from serious luminance saturation when excited by a high-powerdensity blue laser.
基金supported by the National Natural Science Foundation of China(52172156,51832005)the Natural Science Foundation of Fujian Province of China(2023J06005)the Natural Science Foundation of Zhejiang Province(LD22E010001)。
