The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals ...The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping valence-changeable ions. The experimental results were discussed and a new reduction process of the photorefractive LN crystal at a relatively low temperature was proposed, and the reduced crystals showed a good effect in practical use.展开更多
Cubic （Zn,Li）TiO3 powders were synthesized through a modified sol-gel route including the Pechini process via a three-step heat treatment.The as-synthesized （Zn,Li）TiO3 could be stable up to 1000 °C.The diele...Cubic （Zn,Li）TiO3 powders were synthesized through a modified sol-gel route including the Pechini process via a three-step heat treatment.The as-synthesized （Zn,Li）TiO3 could be stable up to 1000 °C.The dielectric constant and dielectric loss tangent of all the synthesized （Zn,Li）TiO3 samples at different measurement frequencies showed the similar tendency.At the same frequency,the dielectric constant and the dielectric loss tangent of （Zn,Li）TiO3 samples decreased and increased,respectively,with the lithium doping content increase.The as-prepared （Zn,Li）TiO3 showed improved microwave dielectric properties,and its maximum value of quality factor could reach 34000 GHz.展开更多
The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,...The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,the intrinsically p-type Mg3Sb2 shows low figure of merit（z T = 0.23 at 723 K） for its poor electrical conductivity.In this study,a series of Mg（3-x）LixSb2 bulk materials have been prepared by high-energy ball milling and spark plasma sintering（SPS） process.Electrical transport measurements on these materials revealed significant improvement on the power factor with respect to the undoped sample,which can be essentially attributed to the increased carrier concentration,leading to a maximum z T of0.59 at 723 K with the optimum doping level x = 0.01.Additionally,the engineering z T and energy conversion efficiency are calculated to be 0.235 and 4.89%,respectively.To our best knowledge,those are the highest values of all reported p-type Mg3Sb2-based compounds with single element doping.展开更多
Powdery Li^(+)-imprinted manganese oxides adsorbent was widely used to the recovery of Li^(+),but there are some difficulties,such as poor stability in acid solution,inconvenience of operation and separation.In this w...Powdery Li^(+)-imprinted manganese oxides adsorbent was widely used to the recovery of Li^(+),but there are some difficulties,such as poor stability in acid solution,inconvenience of operation and separation.In this work,a useful hydrogel composite based H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide(HMTO-rGO/PAM)was fabricated by thermal initiation method with promising stable,conductive and selective properties.The resulting materials were characterized by field emission scanning electron microscope,infrared absorption spectrum,X-ray diffraction,X-ray photoelectron spectroscopy and electrochemical techniques.The recovery of Li^(+)was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process.The adsorption capacity of 51.5 mg·g^(-1)could be achieved with an initial Li^(+)concentration of 200 mg·L^(-1)in pH 10,at 45℃ for 12 h.Li^(+)ions could be quickly desorbed by cyclic voltammetry(CV)in pH 3,0.1 mol·L^(-1)HCl/NH;Cl accompanying the exchange of Li^(+)and H+(NH;)and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.展开更多
This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encou...This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells(hASCs)and the osteogenic differentiation-related gene expression,essential for osteogenesis.In-situ X-ray diffraction(XRD)and in-situ 1H nuclear magnetic resonance(1H NMR)measurements proved the precipitation of brushite,as main phase,and monetite,indicating that Li+favored the formation of monetite under certain conditions.Li+was detected in the remaining pore solution in significant amounts after the completion of hydration.Isothermal calorimetry results showed an accelerating effect of Li+,especially for low concentration of the setting retarder(phytic acid).A decrease of initial and final setting times with increasing amount of Li+was detected and setting times could be well adjusted by varying the setting retarder concentration.The cements presented compressive mechanical strength within the ranges reported for cancellous bone.In vitro assays using hASCs showed normal metabolic and proliferative levels.The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+for increasing the in vivo bone density.The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.展开更多
H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiP...H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiPF6/(EC-EMC-DMC),respectively.PH,PLI and PHLI were all characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) spectrometry.With 1 mol/L LiPF6/(EC-EMC-DMC) as electrolyte,PH,PHLI and PLI were used as the active materials of symmetric non-aqueous redox supercapacitors.PLI shows the highest initial specific capacitance of 120 F/g(47 F/g for PH and 66 F/g for PHLI) among three samples.After 500 cycles,the specific capacitance of PLI remains 75 F/g,indicating the good cycleability.展开更多
A nanoporous N-doped reduced graphene oxide（p-N-rGO） was prepared through carbothermal reaction between graphene oxide and ammonium-containing oxometalates as sulfur host for Li-S batteries.The p-N-rGO sheets have a...A nanoporous N-doped reduced graphene oxide（p-N-rGO） was prepared through carbothermal reaction between graphene oxide and ammonium-containing oxometalates as sulfur host for Li-S batteries.The p-N-rGO sheets have abundant nanopores with diameters of 10-40 nm and the nitrogen content is 2.65 at%.When used as sulfur cathode,the obtained p-N-rGO/S composite has a high reversible capacity of 1110mAhg^-1 at 1C rate and stable cycling performance with 781.8 mAhg-1 retained after 110 cycles,much better than those of the rGO/S composite.The enhanced electrochemical performance is ascribed to the rational combination of nanopores and N-doping,which provide efficient contact and wetting with the electrolyte,accommodate volume expansion and immobilize polysulfides during cycling.展开更多
A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merge...A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0–4.3 V, Li3Nd0.08V1.92（PO4）3exhibits an initial discharge capacity of 115.8 m Ah/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51 st cycle.In addition, Li3Nd0.05V1.95（PO4）3holds at 100.4 m Ah/g after 80 cycles at 0.2 C with a capacity retention of92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92（PO4）3decreased compared with the un-doped one.展开更多
文摘The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping valence-changeable ions. The experimental results were discussed and a new reduction process of the photorefractive LN crystal at a relatively low temperature was proposed, and the reduced crystals showed a good effect in practical use.
基金Supported by the National Natural Science Foundation of China(Nos.20731001,20871015 and 50725415)the Program for New Century Excellent Talents in University,China(NCET)+1 种基金the National Basic Research Program of China(No.2007CB613601)the Program for Changjiang Scholars and Innovative Research Team in University,China(No.IRT0708)
文摘Cubic （Zn,Li）TiO3 powders were synthesized through a modified sol-gel route including the Pechini process via a three-step heat treatment.The as-synthesized （Zn,Li）TiO3 could be stable up to 1000 °C.The dielectric constant and dielectric loss tangent of all the synthesized （Zn,Li）TiO3 samples at different measurement frequencies showed the similar tendency.At the same frequency,the dielectric constant and the dielectric loss tangent of （Zn,Li）TiO3 samples decreased and increased,respectively,with the lithium doping content increase.The as-prepared （Zn,Li）TiO3 showed improved microwave dielectric properties,and its maximum value of quality factor could reach 34000 GHz.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1601213 and 51572287)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH013)
文摘The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,the intrinsically p-type Mg3Sb2 shows low figure of merit（z T = 0.23 at 723 K） for its poor electrical conductivity.In this study,a series of Mg（3-x）LixSb2 bulk materials have been prepared by high-energy ball milling and spark plasma sintering（SPS） process.Electrical transport measurements on these materials revealed significant improvement on the power factor with respect to the undoped sample,which can be essentially attributed to the increased carrier concentration,leading to a maximum z T of0.59 at 723 K with the optimum doping level x = 0.01.Additionally,the engineering z T and energy conversion efficiency are calculated to be 0.235 and 4.89%,respectively.To our best knowledge,those are the highest values of all reported p-type Mg3Sb2-based compounds with single element doping.
基金supported by the Ministry of Science and Technology of China(Science and Technology to Boost Economy 2020Key Project,SQ2020YFF0412719 and SQ2020YFF0404901)The Key Research and Development and Transformation Program Funding in Qinghai Province(2021-GX-105)Anhui Province Key Research and Development Plan(1804e03020316)。
文摘Powdery Li^(+)-imprinted manganese oxides adsorbent was widely used to the recovery of Li^(+),but there are some difficulties,such as poor stability in acid solution,inconvenience of operation and separation.In this work,a useful hydrogel composite based H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide(HMTO-rGO/PAM)was fabricated by thermal initiation method with promising stable,conductive and selective properties.The resulting materials were characterized by field emission scanning electron microscope,infrared absorption spectrum,X-ray diffraction,X-ray photoelectron spectroscopy and electrochemical techniques.The recovery of Li^(+)was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process.The adsorption capacity of 51.5 mg·g^(-1)could be achieved with an initial Li^(+)concentration of 200 mg·L^(-1)in pH 10,at 45℃ for 12 h.Li^(+)ions could be quickly desorbed by cyclic voltammetry(CV)in pH 3,0.1 mol·L^(-1)HCl/NH;Cl accompanying the exchange of Li^(+)and H+(NH;)and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.
基金funded by the Portuguese Foundation for Science and Technology(FCT)and the German Academic Exchange Service(Deutscher Akademischer Austauschdienst,DAAD)for the transnational cooperation FCT/DAAD 2018-2019FRM acknowledges her contract under the Transitional Rule DL 57/2016(CTTI-57/18-I3BS(5))attributed by the FCT.VPR acknowledges the Junior Researcher contracts(POCI-01-0145-FEDER-031367+1 种基金POCI-01-0145-FEDER-029139)under the projects Fun4TE project(PTDC/EMD-EMD/31367/2017)and B-Liver(PTDC/EMD-EMD/29139/2017)attributed by the FCT.The authors also thank the funds provided under the distinctions attributed to JMO(IF/01285/2015)and SP(CEECIND/03673/2017).Furthermore,funding by the German Research Foundation(Deutsche Forschungsgemeinschaft,DFG),Grant Nr.HU 2498/1-1GB 1/22-1,is acknowledged.
文摘This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells(hASCs)and the osteogenic differentiation-related gene expression,essential for osteogenesis.In-situ X-ray diffraction(XRD)and in-situ 1H nuclear magnetic resonance(1H NMR)measurements proved the precipitation of brushite,as main phase,and monetite,indicating that Li+favored the formation of monetite under certain conditions.Li+was detected in the remaining pore solution in significant amounts after the completion of hydration.Isothermal calorimetry results showed an accelerating effect of Li+,especially for low concentration of the setting retarder(phytic acid).A decrease of initial and final setting times with increasing amount of Li+was detected and setting times could be well adjusted by varying the setting retarder concentration.The cements presented compressive mechanical strength within the ranges reported for cancellous bone.In vitro assays using hASCs showed normal metabolic and proliferative levels.The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+for increasing the in vivo bone density.The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.
基金Project(2008AA03Z207) supported by the National Hi-tech Research and Development Program of China
文摘H+ doped polyaniline nanofibre(PH) was synthesized by interfacial polymerization and polyanilines doped with Li salt(PLI and PHLI) were prepared by immersing emeraldine base(EB) and H+ doped polyaniline in 1 mol/L LiPF6/(EC-EMC-DMC),respectively.PH,PLI and PHLI were all characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) spectrometry.With 1 mol/L LiPF6/(EC-EMC-DMC) as electrolyte,PH,PHLI and PLI were used as the active materials of symmetric non-aqueous redox supercapacitors.PLI shows the highest initial specific capacitance of 120 F/g(47 F/g for PH and 66 F/g for PHLI) among three samples.After 500 cycles,the specific capacitance of PLI remains 75 F/g,indicating the good cycleability.
基金Financial support from the Research Project of National University of Defense Technology (No. ZDYYjc Yj20140701)
文摘A nanoporous N-doped reduced graphene oxide（p-N-rGO） was prepared through carbothermal reaction between graphene oxide and ammonium-containing oxometalates as sulfur host for Li-S batteries.The p-N-rGO sheets have abundant nanopores with diameters of 10-40 nm and the nitrogen content is 2.65 at%.When used as sulfur cathode,the obtained p-N-rGO/S composite has a high reversible capacity of 1110mAhg^-1 at 1C rate and stable cycling performance with 781.8 mAhg-1 retained after 110 cycles,much better than those of the rGO/S composite.The enhanced electrochemical performance is ascribed to the rational combination of nanopores and N-doping,which provide efficient contact and wetting with the electrolyte,accommodate volume expansion and immobilize polysulfides during cycling.
基金supported by the National Key Program for Basic Research of China(No.2009CB220100)National High-tech 863Key Program(No.2011AA11A235)Basic Research Fund of Beijing Institute of Technology(No.3100012211111)
文摘A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0–4.3 V, Li3Nd0.08V1.92（PO4）3exhibits an initial discharge capacity of 115.8 m Ah/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51 st cycle.In addition, Li3Nd0.05V1.95（PO4）3holds at 100.4 m Ah/g after 80 cycles at 0.2 C with a capacity retention of92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92（PO4）3decreased compared with the un-doped one.
