The shell structure design has been recognized as a highly efficient strategy to buffer the severe volume expansion and consecutive pulverization of conversion-type anodes.Nevertheless,construction of a functional she...The shell structure design has been recognized as a highly efficient strategy to buffer the severe volume expansion and consecutive pulverization of conversion-type anodes.Nevertheless,construction of a functional shell with a stabilized structure that meets the demands of both high electronic conductivity and feasible pathways for Na^(+)ions has been a challenge so far.Herein,we design a two-in-one shell configuration for bimetal selenides to achieve fast sodium storage within broadened voltage windows.The hybridized shell,which benefits from the combination of titanium dioxide quantum dots and amorphous carbon,can not only effectively buffer the strain and maintain structural integrity but also allow facile and reversible transport of electrons and Na^(+)uptake for electrode materials during sodiation/desodiation processes,resulting in increased reaction kinetics and diffusion of sodium ions,conferring many benefits to the functionality of conversion-type electrode materials.As a representative material,Ni-CoSe_(2) with such structural engineering shows a reversible capacity of 515 mAh g^(−1)at 0.1 A g^(−1)and a stable capacity of 416 mAh g^(−1)even at 6.4 A g^(−1);more than 80%of the capacity at 0.1 A g^(−1)could be preserved,so that this strategy holds great promise for designing fast-charging conversion-type anodes in the future.展开更多
This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc mod...This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger-Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid ele- ment, a hybrid-stress solid-shell element is formulated. The presented finite shell element is able to model arbitrary curved shell structures. Non-linear numerical examples demonstrate the ability of the proposed model to analyze nonlinear piezoelectric devices.展开更多
PAM-ZnS hybrid microspheres with diameters of 640-660 nm were fabricated in two simple steps: the formation of polyacrylamide（PAM） microspheres via the polymerization of acrylamide in the water phase of a water-in-t...PAM-ZnS hybrid microspheres with diameters of 640-660 nm were fabricated in two simple steps: the formation of polyacrylamide（PAM） microspheres via the polymerization of acrylamide in the water phase of a water-in-toluene emulsion,and the sedimentation of ZnS at the inside or on the surface of the PAM microspheres in the emulsion via the reaction of Zn（AC）2 and Na2S or H2S.ZnS@PAM and PAM@ZnS hybrid microspheres were obtained by the use of Na2S and H2S as the precipitating agent respectively.The hybrid microspheres were characterized with TEM and FTIR spectrum.The XRD results show that ZnS in the hybrid microspheres is in a crystalline state with a face-centered structure.The hybrid microspheres are photoluminescence-active due to the presence of ZnS.展开更多
基金Fundamental Research Funds for the Central Universities,Grant/Award Numbers:531118010111,531118010633National Natural Science Foundation of China,Grant/Award Numbers:22109041,52103313。
文摘The shell structure design has been recognized as a highly efficient strategy to buffer the severe volume expansion and consecutive pulverization of conversion-type anodes.Nevertheless,construction of a functional shell with a stabilized structure that meets the demands of both high electronic conductivity and feasible pathways for Na^(+)ions has been a challenge so far.Herein,we design a two-in-one shell configuration for bimetal selenides to achieve fast sodium storage within broadened voltage windows.The hybridized shell,which benefits from the combination of titanium dioxide quantum dots and amorphous carbon,can not only effectively buffer the strain and maintain structural integrity but also allow facile and reversible transport of electrons and Na^(+)uptake for electrode materials during sodiation/desodiation processes,resulting in increased reaction kinetics and diffusion of sodium ions,conferring many benefits to the functionality of conversion-type electrode materials.As a representative material,Ni-CoSe_(2) with such structural engineering shows a reversible capacity of 515 mAh g^(−1)at 0.1 A g^(−1)and a stable capacity of 416 mAh g^(−1)even at 6.4 A g^(−1);more than 80%of the capacity at 0.1 A g^(−1)could be preserved,so that this strategy holds great promise for designing fast-charging conversion-type anodes in the future.
基金Supported by the National Natural Science Foundation of China (Grant No. 10672111)the Major Project of the Natural Science Foundation of Jiangsu Province (Grant No. BK2006725)
文摘This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger-Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid ele- ment, a hybrid-stress solid-shell element is formulated. The presented finite shell element is able to model arbitrary curved shell structures. Non-linear numerical examples demonstrate the ability of the proposed model to analyze nonlinear piezoelectric devices.
文摘PAM-ZnS hybrid microspheres with diameters of 640-660 nm were fabricated in two simple steps: the formation of polyacrylamide（PAM） microspheres via the polymerization of acrylamide in the water phase of a water-in-toluene emulsion,and the sedimentation of ZnS at the inside or on the surface of the PAM microspheres in the emulsion via the reaction of Zn（AC）2 and Na2S or H2S.ZnS@PAM and PAM@ZnS hybrid microspheres were obtained by the use of Na2S and H2S as the precipitating agent respectively.The hybrid microspheres were characterized with TEM and FTIR spectrum.The XRD results show that ZnS in the hybrid microspheres is in a crystalline state with a face-centered structure.The hybrid microspheres are photoluminescence-active due to the presence of ZnS.
