Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further p...Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.展开更多
In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium ...In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium batteries(ASSLB)using sulfide solid electrolyte.However,the electrochemical performances are still not satisfactory,due to the high interfacial resistance caused by severe interfacial instability between sulfide solid electrolyte and oxide cathode,especially Ni-rich oxide cathodes,in charge-discharge process.Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)material at present is one of the most key cathode candidates to achieve the high energy density up to 300 Wh kg^-1 in liquid LIB,but rarely investigated in ASSLB using sulfide electrolyte.To design the stable interface between NCM811 and sulfide electrolyte should be extremely necessary.In this work,in view of our previous work,LiNbO3 coating with about 1 wt% content is adopted to improve the interfacial stability and the electrochemical performances of NCM811 cathode in ASSLB using Li10GeP2S12 solid electrolyte.Consequently,LiNbO3-coated NCM811 cathode displays the higher discharge capacity and rate performance than the reported oxide electrodes in ASSLB using sulfide solid electrolyte to our knowledge.展开更多
The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and li...The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and lithium niobate type MnTiO3 reversibly transforms at room temperature to perovskite at 2.0 GPa. Bulk moduli （K300） of ilmenite, lithium niobate and perovskite are 174（4） GPa, 179 （8） GPa, and 208（5） GPa, respectively （at fixed first pressure derivative K＇ = 4）. The Griineisen parameter T has been estimated to be 1.28 for ilmenite and 1.75 for perovskite. In ilmenite phase, TiO6 octahedra become more regular with increasing pressure. In perovskite phase structural distortion increases with pressure increase.展开更多
We report an electro-optically(EO)tunable microdisk laser fabricated on the erbium(Er^(3+))-doped lithium niobate on insulator(LNOI) substrate.By applying a variable voltage on a pair of integrated chromium(Cr) microe...We report an electro-optically(EO)tunable microdisk laser fabricated on the erbium(Er^(3+))-doped lithium niobate on insulator(LNOI) substrate.By applying a variable voltage on a pair of integrated chromium(Cr) microelectrodes fabricated near the LNOI microdisk,electro-optic modulation with an effective resonance-frequency tuning rate of 2.6 GHz/100 V has been achieved.This gives rise to a tuning range of 45 pm when the electric voltage is varied between-200 V and 200 V.展开更多
All-solid-state batteries(ASSB) with lithium anode have attracted ever-increasing attention towards developing safer batteries with high energy densities.While great advancement has been achieved in developing solid e...All-solid-state batteries(ASSB) with lithium anode have attracted ever-increasing attention towards developing safer batteries with high energy densities.While great advancement has been achieved in developing solid electrolytes(SE) with superb ionic conductivity rivalling that of the current liquid technology,it has yet been very difficult in their successful application to ASSBs with sustaining rate and cyclic performances.Here in this work,we have realized a stable ASSB using the Li_(6.25)PS_(5.25)Cl_(0.75) fast ionconducting electrolyte together with LiNbO_3 coated LiCoO_2 as cathode and lithium foil as the anode.The effective diffusion coefficient of Li-ions in the battery is higher than 10^(-12) cm~2 s^(-1),and the significantly enhanced electrochemical matching at the cathode-electrolyte interface was essential to enable long-term stability against high oxidation potential,with the LCO@LNO/Li_(6.25)PS_(5.25)Cl_(0.75)/Li battery to retain 74.12% capacity after 430 cycles at 100 μA cm-2 and 59.7% of capacity after 800 cycles at 50 μA cm^(-2),at a high charging cut-off voltage of 4.2 V.This demonstrates that the Li_(6.25)PS_(5.25)Cl_(0.75) can be an excellent electrolyte for the realization of stable ASSBs with high-voltage cathodes and metallic lithium as anode,once the electrochemical compatibility between cathode and electrolyte can be addressed with a suitable buffer coating.展开更多
Within the framework of the linearized theory of electroelastic wave propagation,a model of a piezoelectric structure with a prestressed functionally graded coating made of piezoceramics of a trigonal system with a sy...Within the framework of the linearized theory of electroelastic wave propagation,a model of a piezoelectric structure with a prestressed functionally graded coating made of piezoceramics of a trigonal system with a symmetry class of 3m is considered.The ferroelectric LiNbO_(3) is used as the main material of the structure.The initial deformed state of the coating material is homogeneous,induced by the action of initial mechanical stresses and an external electrostatic field,the properties of the coating continuously change in thickness.By the example of the problem of the propagation of SH-waves from a remote source for structures with an inhomogeneous prestressed coating in the case of an electrically free and short-circuited surface,the influence of the nature and localization of the inhomogeneity of the coating on the features of SAW propagation is studied.The separate and combined effects of initial actions on changes in the physical properties of the structure,the transformation of the surface wave field,and the change in the SAW velocities in a wide frequency range is studied.The results obtained in this work are useful for understanding the dynamic processes in prestressed piezoelectric structures,in the optimization and design of new structures and devices on SAW with high performance characteristics.展开更多
An iterative procedure is proposed for the variational analysis of Ti:LiNbO3 optical waveguides. A trial solution for the dominant electric field profile of arbitrary-order eigenmodes in strip waveguides and two coupl...An iterative procedure is proposed for the variational analysis of Ti:LiNbO3 optical waveguides. A trial solution for the dominant electric field profile of arbitrary-order eigenmodes in strip waveguides and two coupled waveguides is proposed and its parameters are determined using the variational method. The results calculated using this method agree well with those obtained using the finite-element method. The present method has been used to check the accuracy of the effective index method as well as a quasi-analytical technique based on the effective index method. The results show that the effective index method is generally accurate for the fundamental mode and becomes less accurate for higher-order vertical modes.展开更多
文摘Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.
基金financially supported partly by the National Key Research and Development Program of China (2018YFB0104302)NSFC (21503148)Major Programs of the Innovation Driven Plan of Guilin (No. 20160203)
文摘In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium batteries(ASSLB)using sulfide solid electrolyte.However,the electrochemical performances are still not satisfactory,due to the high interfacial resistance caused by severe interfacial instability between sulfide solid electrolyte and oxide cathode,especially Ni-rich oxide cathodes,in charge-discharge process.Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)material at present is one of the most key cathode candidates to achieve the high energy density up to 300 Wh kg^-1 in liquid LIB,but rarely investigated in ASSLB using sulfide electrolyte.To design the stable interface between NCM811 and sulfide electrolyte should be extremely necessary.In this work,in view of our previous work,LiNbO3 coating with about 1 wt% content is adopted to improve the interfacial stability and the electrochemical performances of NCM811 cathode in ASSLB using Li10GeP2S12 solid electrolyte.Consequently,LiNbO3-coated NCM811 cathode displays the higher discharge capacity and rate performance than the reported oxide electrodes in ASSLB using sulfide solid electrolyte to our knowledge.
基金an Alexander von Humboldt Fellowship in Germany and S.Qin acknowledges the financial support of the National Natural Science Foundation of China(Grant No. 40972029)
文摘The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and lithium niobate type MnTiO3 reversibly transforms at room temperature to perovskite at 2.0 GPa. Bulk moduli （K300） of ilmenite, lithium niobate and perovskite are 174（4） GPa, 179 （8） GPa, and 208（5） GPa, respectively （at fixed first pressure derivative K＇ = 4）. The Griineisen parameter T has been estimated to be 1.28 for ilmenite and 1.75 for perovskite. In ilmenite phase, TiO6 octahedra become more regular with increasing pressure. In perovskite phase structural distortion increases with pressure increase.
基金supported by the National Key R&D Program of China (No. 2019YFA0705000)National Natural Science Foundation of China (Nos. 12004116, 11874154, 11734009, 11933005, 11874060, and 61991444)+1 种基金Shanghai Municipal Science and Technology Major Project (No. HZDZX01)Fundamental Research Funds for the Central Universities, and Shanghai Sailing Program (No. 1410400)
文摘We report an electro-optically(EO)tunable microdisk laser fabricated on the erbium(Er^(3+))-doped lithium niobate on insulator(LNOI) substrate.By applying a variable voltage on a pair of integrated chromium(Cr) microelectrodes fabricated near the LNOI microdisk,electro-optic modulation with an effective resonance-frequency tuning rate of 2.6 GHz/100 V has been achieved.This gives rise to a tuning range of 45 pm when the electric voltage is varied between-200 V and 200 V.
基金supported in part by the 1000 Talents Program of China, the Zhengzhou Materials Genome Institute (ZMGI)the Natural Science Foundation of China (Nos. 51001091, 91233101)the Fundamental Research Program from the Ministry of Science and Technology of China (no. 2014CB931704)。
文摘All-solid-state batteries(ASSB) with lithium anode have attracted ever-increasing attention towards developing safer batteries with high energy densities.While great advancement has been achieved in developing solid electrolytes(SE) with superb ionic conductivity rivalling that of the current liquid technology,it has yet been very difficult in their successful application to ASSBs with sustaining rate and cyclic performances.Here in this work,we have realized a stable ASSB using the Li_(6.25)PS_(5.25)Cl_(0.75) fast ionconducting electrolyte together with LiNbO_3 coated LiCoO_2 as cathode and lithium foil as the anode.The effective diffusion coefficient of Li-ions in the battery is higher than 10^(-12) cm~2 s^(-1),and the significantly enhanced electrochemical matching at the cathode-electrolyte interface was essential to enable long-term stability against high oxidation potential,with the LCO@LNO/Li_(6.25)PS_(5.25)Cl_(0.75)/Li battery to retain 74.12% capacity after 430 cycles at 100 μA cm-2 and 59.7% of capacity after 800 cycles at 50 μA cm^(-2),at a high charging cut-off voltage of 4.2 V.This demonstrates that the Li_(6.25)PS_(5.25)Cl_(0.75) can be an excellent electrolyte for the realization of stable ASSBs with high-voltage cathodes and metallic lithium as anode,once the electrochemical compatibility between cathode and electrolyte can be addressed with a suitable buffer coating.
基金This work was performed with a financial support of the Ministry of Science and Higher Education of the Russian Federation(project 01201354242)Russian Foundation of Basic Research(projects 19-08-01051,19-01-00719).
文摘Within the framework of the linearized theory of electroelastic wave propagation,a model of a piezoelectric structure with a prestressed functionally graded coating made of piezoceramics of a trigonal system with a symmetry class of 3m is considered.The ferroelectric LiNbO_(3) is used as the main material of the structure.The initial deformed state of the coating material is homogeneous,induced by the action of initial mechanical stresses and an external electrostatic field,the properties of the coating continuously change in thickness.By the example of the problem of the propagation of SH-waves from a remote source for structures with an inhomogeneous prestressed coating in the case of an electrically free and short-circuited surface,the influence of the nature and localization of the inhomogeneity of the coating on the features of SAW propagation is studied.The separate and combined effects of initial actions on changes in the physical properties of the structure,the transformation of the surface wave field,and the change in the SAW velocities in a wide frequency range is studied.The results obtained in this work are useful for understanding the dynamic processes in prestressed piezoelectric structures,in the optimization and design of new structures and devices on SAW with high performance characteristics.
基金Project supported in part by the National Natural Science Foundation of China,Science Foundation of Guangdong Province,Zhongshan University,Chinese Post-doctoral Committee.
文摘An iterative procedure is proposed for the variational analysis of Ti:LiNbO3 optical waveguides. A trial solution for the dominant electric field profile of arbitrary-order eigenmodes in strip waveguides and two coupled waveguides is proposed and its parameters are determined using the variational method. The results calculated using this method agree well with those obtained using the finite-element method. The present method has been used to check the accuracy of the effective index method as well as a quasi-analytical technique based on the effective index method. The results show that the effective index method is generally accurate for the fundamental mode and becomes less accurate for higher-order vertical modes.
