Lithium-ion batteries(LIBs)with the“double-high”characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics.However,the lithiu...Lithium-ion batteries(LIBs)with the“double-high”characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics.However,the lithium ion(Li+)-storage performance of the most commercialized lithium cobalt oxide(LiCoO_(2),LCO)cathodes is still far from satisfactory in terms of high-voltage and fast-charging capabilities for reaching the double-high target.Herein,we systematically summarize and discuss high-voltage and fast-charging LCO cathodes,covering in depth the key fundamental challenges,latest advancements in modification strategies,and future perspectives in this field.Comprehensive and elaborated discussions are first presented on key fundamental challenges related to structural degradation,interfacial instability,the inhomogeneity reactions,and sluggish interfacial kinetics.We provide an instructive summary of deep insights into promising modification strategies and underlying mechanisms,categorized into element doping(Li-site,cobalt-/oxygen-site,and multi-site doping)for improved Li+diffusivity and bulkstructure stability;surface coating(dielectrics,ionic/electronic conductors,and their combination)for surface stability and conductivity;nanosizing;combinations of these strategies;and other strategies(i.e.,optimization of the electrolyte,binder,tortuosity of electrodes,charging protocols,and prelithiation methods).Finally,forward-looking perspectives and promising directions are sketched out and insightfully elucidated,providing constructive suggestions and instructions for designing and realizing high-voltage and fast-charging LCO cathodes for next-generation double-high LIBs.展开更多
Application of amorphous V2O5/carbon/ncodymium oxide （Nd2O3） composite is one ot ways to surmount me lower electrical conductivity of V2O5. A new type of V2O5/carbon/Nd2O3 composite was prepared by mixing vanadium o...Application of amorphous V2O5/carbon/ncodymium oxide （Nd2O3） composite is one ot ways to surmount me lower electrical conductivity of V2O5. A new type of V2O5/carbon/Nd2O3 composite was prepared by mixing vanadium oxide hydrosol, acetone, carbon and Nd2O3 powder. High rate discharge/charge property of the composite electrode was tested electrochemically. This composite with Nd2O3 added shows the improvement of not only the discharge capacity but also cycle durability discharge capacity. The rate capability of the composite cathode also increases with the addition of Nd2O3. Even at 10 A·g^-1 current density, a capacity of about 250 mAh·g^-1 was obtained at 25 ℃. This enhanced rate capability and cycle life are probably caused by the increase in porosity of open pores and short diffusion length of the active material on the lithium-ion insertion.展开更多
The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after...The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after isothermal oxidation at 900 ℃ for different times were observed. The experiments showed that the coatings on steel substrate were not deteriorated and the substrate was protected well, being exposed to high temperatures up to 900 ℃ . The coatings withstood more than ten times thermal shock tests without any coating separation. The thermal expansion coefficient of the coatings was measured, revealing not much difference between it and that of steel substrate. After exposure at high temperature, the coatings were still adhered to steel substrate well. Isothermal mass gain of the coatings at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, exhibiting the oxidation kinetics curve accorded with a parabolic law. The parabolic rate constant of the oxidation kinetic curve is 1.02×10?9 g2·cm?4·s?1 for the first 60 min and from 150 min to 2 880 min the constant is 5.1×10?12 g2·cm?4·s?1.展开更多
Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated....Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity （120 mAh/g） at a discharge rate of 0.2 C （29.6 mA/g）. The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73~ at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.展开更多
We report on the performance of La203/InA1N/GaN metal-oxide-semiconductor high electron mobility transistors （MOSHEMTs） and InA1N/GaN high electron mobility transistors （HEMTs）. The MOSHEMT presents a maximum drai...We report on the performance of La203/InA1N/GaN metal-oxide-semiconductor high electron mobility transistors （MOSHEMTs） and InA1N/GaN high electron mobility transistors （HEMTs）. The MOSHEMT presents a maximum drain current of 961 mA/mm at Vgs = 4 V and a maximum transconductance of 130 mS/mm compared with 710 mA/mm at Vgs = 1 V and 131 mS/mm for the HEMT device, while the gate leakage current in the reverse direction could be reduced by four orders of magnitude. Compared with the HEMT device of a similar geometry, MOSHEMT presents a large gate voltage swing and negligible current collapse.展开更多
High-voltage nickel(Ni)-rich layered oxide-based lithium metal batteries(LMBs)exhibit a great potential in advanced batteries due to the ultra-high energy density.However,it is still necessary to deal with the challen...High-voltage nickel(Ni)-rich layered oxide-based lithium metal batteries(LMBs)exhibit a great potential in advanced batteries due to the ultra-high energy density.However,it is still necessary to deal with the challenges in poor cyclic and thermal stability before realizing practical application where cycling life is considered.Among many improved strategies,mechanical and chemical stability for the electrode electrolyte interface plays a key role in addressing these challenges.Therefore,extensive effort has been made to address the challenges of electrode-electrolyte interface.In this progress,the failure mechanism of Ni-rich cathode,lithium metal anode and electrolytes are reviewed,and the latest breakthrough in stabilizing electrode-electrolyte interface is also summarized.Finally,the challenges and future research directions of Ni-rich LMBs are put forward.展开更多
The AIN ceramics with Y2O3 is prepared by hot-pressing. The phase compositions and their distributions are determined by X-ray, SEM and EPA. Both the relation between bend strength and temperature and the relation bet...The AIN ceramics with Y2O3 is prepared by hot-pressing. The phase compositions and their distributions are determined by X-ray, SEM and EPA. Both the relation between bend strength and temperature and the relation between bend strength and oxidation time in 1300℃ air are investigated. It is found that the bend strength decreases slightly with the increasing of temperature below 1300℃ and decreases violently within 1300 ~ 1500℃ . The samples are oxidized in 1300℃ air and their strength decreases with the increasing of oxidation time. The fracture mechanisms of AIN ceramics with Y2O3 at different temperature and after being oxidized in 1300℃ air are discussed.展开更多
Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batt...Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.展开更多
Ultra high molecular weight polyethylene （UHMWPE） is widely used for articulating surfaces in total hip and knee replacements. In the present work, UHMWPE based polymer composites were synthesized by synergistic rei...Ultra high molecular weight polyethylene （UHMWPE） is widely used for articulating surfaces in total hip and knee replacements. In the present work, UHMWPE based polymer composites were synthesized by synergistic reinforcing of bioactive hydroxyapatite （HA）, bioinert aluminum oxide （Al2O3）, and carbon nanotubes （CNTs） using compression molding. Phase and microstructural analysis suggests retention of UHMWPE and reinforcing phases in the compression molded composites. Microstructural analysis elicited variation in densification due to the size effect of the reinforcing particles. The hybrid composites exhibited hardness, elastic modulus and toughness comparable to that of UHMWPE. The interfacial effect of reinforcement phases has evinced the effectiveness of Al2O3 over HA and CNT reinforcements, depicting synergistic enhancement in hardness and elastic modulus. Weak interfacial bonding of polymer matrix with HA and CNT requires utilization of coupling agents to achieve enhanced mechanical properties without deteriorating cytocompatible properties.展开更多
To obtain homogenous layered oxide Li（Co1/3Ni1/3Mn1/3）O2 as a lithium insertion positive electrode material, the sol-gel process using citric acid as a chelating agent was applied. The material Li（Co1/3Ni1/3Mn1/3）...To obtain homogenous layered oxide Li（Co1/3Ni1/3Mn1/3）O2 as a lithium insertion positive electrode material, the sol-gel process using citric acid as a chelating agent was applied. The material Li（Co1/3Ni1/3Mn1/3）O2 was synthesized at different calcination temperatures. XRD experiment indicated that the layered Li（Co1/3Ni1/3Mn1/3）O2 material could be synthesized at a lower temperature of 800℃, and the oxidation state of Co, Ni, and Mn in the cathode confirmed by XPS were ＋3, ＋2, and ＋4, respectively. SEM observations showed that the synthesized material could form homogenous particle morphology with the particle size of about 200 nm. In spite of different calcination temperatures, the charge-discharge curves of all the samples for the initial cycle were similar, and the cathode synthesized at 900℃ showed a small irreversible capacity loss of 11.24% and a high discharge capacity of 212.2 mAh·g^-1 in the voltage range of 2.9-4.6 V.展开更多
The oxidation performance and tribological properties of the anodized Ti45Al8.5Nb were investigated.Anodization was performed in ethylene glycol containing 0.15 mol/L NH_(4)F.Results showed that the anodized Ti45Al8.5...The oxidation performance and tribological properties of the anodized Ti45Al8.5Nb were investigated.Anodization was performed in ethylene glycol containing 0.15 mol/L NH_(4)F.Results showed that the anodized Ti45Al8.5Nb alloy exhibited good resistance against oxidation.After 100 h oxidation at 1000℃,the mass gain of the anodized Ti45Al8.5Nb alloy was only 0.37 mg/cm^(2).This is attributed to the generation of protective oxide scale.On the other hand,the hardness and elastic modulus of the anodized Ti45Al8.5Nb alloy decreased and then increased with the prolonging of thermal exposure due to the generation of the Al_(2)O_(3)-enriched outermost oxide layer.展开更多
基金supported by the National Key Research and Development Program of China(2022YFA1504100)the National Natural Science Foundation of China(22125903,51872283,and 22005298)+4 种基金Dalian Innovation Support Plan for High Level Talents(2019RT09)Dalian National Laboratory For Clean Energy(DNL),Chinese Academy of Sciences(CAS),DNL Cooperation Fund,CAS(DNL202016 and DNL202019)Dalian Institute of Chemical Physics(DICP I2020032)Exploratory Research Project of Yanchang Petroleum International Limited and DICP(yc-hw-2022ky-01)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(YLU-DNL Fund 2021002 and 2021009).
文摘Lithium-ion batteries(LIBs)with the“double-high”characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics.However,the lithium ion(Li+)-storage performance of the most commercialized lithium cobalt oxide(LiCoO_(2),LCO)cathodes is still far from satisfactory in terms of high-voltage and fast-charging capabilities for reaching the double-high target.Herein,we systematically summarize and discuss high-voltage and fast-charging LCO cathodes,covering in depth the key fundamental challenges,latest advancements in modification strategies,and future perspectives in this field.Comprehensive and elaborated discussions are first presented on key fundamental challenges related to structural degradation,interfacial instability,the inhomogeneity reactions,and sluggish interfacial kinetics.We provide an instructive summary of deep insights into promising modification strategies and underlying mechanisms,categorized into element doping(Li-site,cobalt-/oxygen-site,and multi-site doping)for improved Li+diffusivity and bulkstructure stability;surface coating(dielectrics,ionic/electronic conductors,and their combination)for surface stability and conductivity;nanosizing;combinations of these strategies;and other strategies(i.e.,optimization of the electrolyte,binder,tortuosity of electrodes,charging protocols,and prelithiation methods).Finally,forward-looking perspectives and promising directions are sketched out and insightfully elucidated,providing constructive suggestions and instructions for designing and realizing high-voltage and fast-charging LCO cathodes for next-generation double-high LIBs.
文摘Application of amorphous V2O5/carbon/ncodymium oxide （Nd2O3） composite is one ot ways to surmount me lower electrical conductivity of V2O5. A new type of V2O5/carbon/Nd2O3 composite was prepared by mixing vanadium oxide hydrosol, acetone, carbon and Nd2O3 powder. High rate discharge/charge property of the composite electrode was tested electrochemically. This composite with Nd2O3 added shows the improvement of not only the discharge capacity but also cycle durability discharge capacity. The rate capability of the composite cathode also increases with the addition of Nd2O3. Even at 10 A·g^-1 current density, a capacity of about 250 mAh·g^-1 was obtained at 25 ℃. This enhanced rate capability and cycle life are probably caused by the increase in porosity of open pores and short diffusion length of the active material on the lithium-ion insertion.
文摘The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after isothermal oxidation at 900 ℃ for different times were observed. The experiments showed that the coatings on steel substrate were not deteriorated and the substrate was protected well, being exposed to high temperatures up to 900 ℃ . The coatings withstood more than ten times thermal shock tests without any coating separation. The thermal expansion coefficient of the coatings was measured, revealing not much difference between it and that of steel substrate. After exposure at high temperature, the coatings were still adhered to steel substrate well. Isothermal mass gain of the coatings at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, exhibiting the oxidation kinetics curve accorded with a parabolic law. The parabolic rate constant of the oxidation kinetic curve is 1.02×10?9 g2·cm?4·s?1 for the first 60 min and from 150 min to 2 880 min the constant is 5.1×10?12 g2·cm?4·s?1.
基金supported by the National Natural Science Foundation for Postdoctoral Scientists of China (Grant No. 20090451554)
文摘Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity （120 mAh/g） at a discharge rate of 0.2 C （29.6 mA/g）. The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73~ at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.
基金Project supported by the Basic Science Research Fund for the Central Universities （Grant No. K50511250009）.
文摘We report on the performance of La203/InA1N/GaN metal-oxide-semiconductor high electron mobility transistors （MOSHEMTs） and InA1N/GaN high electron mobility transistors （HEMTs）. The MOSHEMT presents a maximum drain current of 961 mA/mm at Vgs = 4 V and a maximum transconductance of 130 mS/mm compared with 710 mA/mm at Vgs = 1 V and 131 mS/mm for the HEMT device, while the gate leakage current in the reverse direction could be reduced by four orders of magnitude. Compared with the HEMT device of a similar geometry, MOSHEMT presents a large gate voltage swing and negligible current collapse.
基金National Natural Science Foundation of China,Grant/Award Numbers:U21A20311,51971090。
文摘High-voltage nickel(Ni)-rich layered oxide-based lithium metal batteries(LMBs)exhibit a great potential in advanced batteries due to the ultra-high energy density.However,it is still necessary to deal with the challenges in poor cyclic and thermal stability before realizing practical application where cycling life is considered.Among many improved strategies,mechanical and chemical stability for the electrode electrolyte interface plays a key role in addressing these challenges.Therefore,extensive effort has been made to address the challenges of electrode-electrolyte interface.In this progress,the failure mechanism of Ni-rich cathode,lithium metal anode and electrolytes are reviewed,and the latest breakthrough in stabilizing electrode-electrolyte interface is also summarized.Finally,the challenges and future research directions of Ni-rich LMBs are put forward.
文摘The AIN ceramics with Y2O3 is prepared by hot-pressing. The phase compositions and their distributions are determined by X-ray, SEM and EPA. Both the relation between bend strength and temperature and the relation between bend strength and oxidation time in 1300℃ air are investigated. It is found that the bend strength decreases slightly with the increasing of temperature below 1300℃ and decreases violently within 1300 ~ 1500℃ . The samples are oxidized in 1300℃ air and their strength decreases with the increasing of oxidation time. The fracture mechanisms of AIN ceramics with Y2O3 at different temperature and after being oxidized in 1300℃ air are discussed.
基金supported by the National Key Research and Development Program of China (2016YFA202500)the “One Hundred Talent Project” of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (11675255)
文摘Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.
基金funded by the Department of Biotechnology (DBT),Govt.of India
文摘Ultra high molecular weight polyethylene （UHMWPE） is widely used for articulating surfaces in total hip and knee replacements. In the present work, UHMWPE based polymer composites were synthesized by synergistic reinforcing of bioactive hydroxyapatite （HA）, bioinert aluminum oxide （Al2O3）, and carbon nanotubes （CNTs） using compression molding. Phase and microstructural analysis suggests retention of UHMWPE and reinforcing phases in the compression molded composites. Microstructural analysis elicited variation in densification due to the size effect of the reinforcing particles. The hybrid composites exhibited hardness, elastic modulus and toughness comparable to that of UHMWPE. The interfacial effect of reinforcement phases has evinced the effectiveness of Al2O3 over HA and CNT reinforcements, depicting synergistic enhancement in hardness and elastic modulus. Weak interfacial bonding of polymer matrix with HA and CNT requires utilization of coupling agents to achieve enhanced mechanical properties without deteriorating cytocompatible properties.
基金The authors would like to thank the financial support of the Major State Basic Research Development Program of China (No.2002CB613303)the National Natural Science Foundation of China (No.20371038)the Foundation for Innovative Research Team of Hubei Province of China(No.2005ABC004).
文摘To obtain homogenous layered oxide Li（Co1/3Ni1/3Mn1/3）O2 as a lithium insertion positive electrode material, the sol-gel process using citric acid as a chelating agent was applied. The material Li（Co1/3Ni1/3Mn1/3）O2 was synthesized at different calcination temperatures. XRD experiment indicated that the layered Li（Co1/3Ni1/3Mn1/3）O2 material could be synthesized at a lower temperature of 800℃, and the oxidation state of Co, Ni, and Mn in the cathode confirmed by XPS were ＋3, ＋2, and ＋4, respectively. SEM observations showed that the synthesized material could form homogenous particle morphology with the particle size of about 200 nm. In spite of different calcination temperatures, the charge-discharge curves of all the samples for the initial cycle were similar, and the cathode synthesized at 900℃ showed a small irreversible capacity loss of 11.24% and a high discharge capacity of 212.2 mAh·g^-1 in the voltage range of 2.9-4.6 V.
基金financial supports from the National Natural Science Foundation of China (No. 51971205)the Guangdong Basic and Applied Basic Research Foundation, China (No. 2021B1515020056)the Shenzhen Fundamental Research Program, China (No. JCYJ20190807154005593)。
文摘The oxidation performance and tribological properties of the anodized Ti45Al8.5Nb were investigated.Anodization was performed in ethylene glycol containing 0.15 mol/L NH_(4)F.Results showed that the anodized Ti45Al8.5Nb alloy exhibited good resistance against oxidation.After 100 h oxidation at 1000℃,the mass gain of the anodized Ti45Al8.5Nb alloy was only 0.37 mg/cm^(2).This is attributed to the generation of protective oxide scale.On the other hand,the hardness and elastic modulus of the anodized Ti45Al8.5Nb alloy decreased and then increased with the prolonging of thermal exposure due to the generation of the Al_(2)O_(3)-enriched outermost oxide layer.
