The development of zero and negative therma expansion(i.e.,ZTE and NTE)materials is of crucial importance to the control of undesirable thermal expansion for high-precision devices.In the present work,ZTE and NTE were...The development of zero and negative therma expansion(i.e.,ZTE and NTE)materials is of crucial importance to the control of undesirable thermal expansion for high-precision devices.In the present work,ZTE and NTE were obtained in directionally-solidified Mn_(x)Fe_(5-x)Si_(3)alloys with a strong<001>texture,in striking contrast to positive thermal expansion in their isotropic counterparts Magnetometry and in-situ X-ray diffraction(XRD)measurements were performed to uncover the origin of the anomalous thermal expansion.Magnetic measurements indicate a strong easy-plane magnetocrystalline anisotropy in the textured samples,where the magnetic moments are aligned within the ab plane of the hexagonal structure Temperature-dependent XRD on the x=1 sample reveals a ZTE character in the ab plane that is coupled to a ferromagnetic transition.As a result,the macroscopic ZTE(~0.22×10^(-6)K^(-1))in the x=1 sample can be attributed to the microscopic magneto volume effect within the ab plane,which is realized by the introduction of the<001>-textured microstructure.Besides,the competition between antiferromagnetic and ferromagnetic exchange coupling leads to NTE in textured x=1.5 and 2 samples.Additionally,textured x=1 sample displays enhanced magnetocaloric properties as compared to the conventional counterparts with randomly-oriented grains.Consequently this work demonstrates a new strategy toward the exploration of anomalous thermal expansion properties as well as the enhancement of magnetocaloric properties for materials with a strong magnetocrystalline anisotropy.展开更多
(MnFe)2(P, Si)-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect (MCE), tunable working t...(MnFe)2(P, Si)-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect (MCE), tunable working temperature range and low material cost. The giant MCE in the (Mn, Fe)2(P, Si)-type compounds originates from strong mag- netoelastic coupling, where the lattice degrees of freedom and spin degrees of freedom are efficiently coupled. The tunability of the phase transition, in terms of the critical temperature and the character of the phase transition, is essentially attributed to the changes in the magnetoelastic coupling in the (Mn, Fe)2(P, Si)-type compounds. In this review, not only the fundamentals of the magnetoelastic coupling but also the related practical aspects such as magnetocaloric performance, hysteresis issue and mechanical stability are discussed for the (Mn, Fe)2(P, Si)- type compounds. Additionally, some future fundamental studies on the MCE as well as possible ways of solving the hysteresis and fracture issues are proposed.展开更多
All-solid-state Li-Se battery shows great potential as a candidate for next-generation energy storage devices due to its high energy density and safety.However,the low ionic conductivity of the solid electrolytes and ...All-solid-state Li-Se battery shows great potential as a candidate for next-generation energy storage devices due to its high energy density and safety.However,the low ionic conductivity of the solid electrolytes and large volume changes of Se active materials are two of the major issues that limit its applications.Herein,a simple solid-state reaction method is applied to synthesize chlorine-rich argyrodite Li_(5.5)PS_(4.5)CI_(1.5)electrolyte with high conductivity of 6.25 mS·cm^(-1)at room temperature.Carbon nanotube(CNT)is introduced as the host for Se to obtain Se/CNT composite with both enhanced electronic conductivity and lower volume expansion during the electrochemical reaction process.All-solid-state Li-Se battery using Li_(5.5)PS_(4.5)CI_(1.5)as solid electrolyte combined with Se/CNT cathode and Li-In anode shows a discharge capacity of 866 mAh·g-1for the 2nd cycle under0.433 mA·cm-2at room temperature.Moreover,the assembled battery delivers a high discharge capacity of1026 mAh·g^(-1)for the 2nd cycle when cycled at the same current density at 60℃and maintains a discharge capacity of 380 mAh·g^(-1)after 150 cycles.Owing to the high Li-ion conductivity of Li_(5.5)PS_(4.5)CI_(1.5)electrolyte,the assembled battery displays a high discharge capacity of 344 mAh·g^(-1)under 0.113 mA·cm^(-2)at-20℃C and remains 66.1%after200 cycles.In addition,this all-solid-state Li-Se battery shows ultralong cycling performances up to 1000 cycles under 0.433 mA·cm^(-2)at-20℃.This work offers the design clue to fabricate the all-solid-state Li-Se battery workable at different operating temperatures with an ultralong cycling life.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.12004179,U1832191,51801102,52271180,52001167 and 52101236)Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology+1 种基金the Fundamental Research Funds for the Central Universities(No.30922010802)the Sino-German Mobility Program from the Sino-German Center for Research Promotion(SGC)(No.M-0447)。
文摘The development of zero and negative therma expansion(i.e.,ZTE and NTE)materials is of crucial importance to the control of undesirable thermal expansion for high-precision devices.In the present work,ZTE and NTE were obtained in directionally-solidified Mn_(x)Fe_(5-x)Si_(3)alloys with a strong<001>texture,in striking contrast to positive thermal expansion in their isotropic counterparts Magnetometry and in-situ X-ray diffraction(XRD)measurements were performed to uncover the origin of the anomalous thermal expansion.Magnetic measurements indicate a strong easy-plane magnetocrystalline anisotropy in the textured samples,where the magnetic moments are aligned within the ab plane of the hexagonal structure Temperature-dependent XRD on the x=1 sample reveals a ZTE character in the ab plane that is coupled to a ferromagnetic transition.As a result,the macroscopic ZTE(~0.22×10^(-6)K^(-1))in the x=1 sample can be attributed to the microscopic magneto volume effect within the ab plane,which is realized by the introduction of the<001>-textured microstructure.Besides,the competition between antiferromagnetic and ferromagnetic exchange coupling leads to NTE in textured x=1.5 and 2 samples.Additionally,textured x=1 sample displays enhanced magnetocaloric properties as compared to the conventional counterparts with randomly-oriented grains.Consequently this work demonstrates a new strategy toward the exploration of anomalous thermal expansion properties as well as the enhancement of magnetocaloric properties for materials with a strong magnetocrystalline anisotropy.
基金financially supported by the Key Research & Development Program of Jiangsu Province(No.BE2017102)
文摘(MnFe)2(P, Si)-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect (MCE), tunable working temperature range and low material cost. The giant MCE in the (Mn, Fe)2(P, Si)-type compounds originates from strong mag- netoelastic coupling, where the lattice degrees of freedom and spin degrees of freedom are efficiently coupled. The tunability of the phase transition, in terms of the critical temperature and the character of the phase transition, is essentially attributed to the changes in the magnetoelastic coupling in the (Mn, Fe)2(P, Si)-type compounds. In this review, not only the fundamentals of the magnetoelastic coupling but also the related practical aspects such as magnetocaloric performance, hysteresis issue and mechanical stability are discussed for the (Mn, Fe)2(P, Si)- type compounds. Additionally, some future fundamental studies on the MCE as well as possible ways of solving the hysteresis and fracture issues are proposed.
基金financially supported by the National Key Research and Development Program (No. 2021YFB2400300)the National Natural Science Foundation of China (No.52177214)the Certificate of China Post-doctoral Science Foundation Grant (No.2019M652634)
文摘All-solid-state Li-Se battery shows great potential as a candidate for next-generation energy storage devices due to its high energy density and safety.However,the low ionic conductivity of the solid electrolytes and large volume changes of Se active materials are two of the major issues that limit its applications.Herein,a simple solid-state reaction method is applied to synthesize chlorine-rich argyrodite Li_(5.5)PS_(4.5)CI_(1.5)electrolyte with high conductivity of 6.25 mS·cm^(-1)at room temperature.Carbon nanotube(CNT)is introduced as the host for Se to obtain Se/CNT composite with both enhanced electronic conductivity and lower volume expansion during the electrochemical reaction process.All-solid-state Li-Se battery using Li_(5.5)PS_(4.5)CI_(1.5)as solid electrolyte combined with Se/CNT cathode and Li-In anode shows a discharge capacity of 866 mAh·g-1for the 2nd cycle under0.433 mA·cm-2at room temperature.Moreover,the assembled battery delivers a high discharge capacity of1026 mAh·g^(-1)for the 2nd cycle when cycled at the same current density at 60℃and maintains a discharge capacity of 380 mAh·g^(-1)after 150 cycles.Owing to the high Li-ion conductivity of Li_(5.5)PS_(4.5)CI_(1.5)electrolyte,the assembled battery displays a high discharge capacity of 344 mAh·g^(-1)under 0.113 mA·cm^(-2)at-20℃C and remains 66.1%after200 cycles.In addition,this all-solid-state Li-Se battery shows ultralong cycling performances up to 1000 cycles under 0.433 mA·cm^(-2)at-20℃.This work offers the design clue to fabricate the all-solid-state Li-Se battery workable at different operating temperatures with an ultralong cycling life.