In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treat...In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treatment.The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency.Ni/T-Nb_(2)O_(5)nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system,which provides effective buffering during the lithiation/delithiation process for cycling stability.The Ni/TNb_(2)O_(5)@CNFs show high surface area(26.321 m^(2)·g^(-1))and mesoporous microstructure,resulting in higher capacity and excellent rate performance.The Ni/T-Nb_(2)O_(5)@CNFs exhibit a remarkable capacity of 437 mAh·g^(-1)at a current density of0.5 A·g^(-1)after 230 cycles and a capacity of 173 mAh·g^(-1)at a current density up to 10.0 A·g^(-1)after 1400 cycles.This work indicates that nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs.展开更多
Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic...Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs performances.The results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,respectively.The delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)layer.After 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)TBCs.The cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.展开更多
基金Project(51274248) supported by the National Natural Science Foundation of ChinaProjects(2015DFR50580,2013DFA31440) supported by the International Scientific and Technological Cooperation Projects of China
基金The authors are grateful for the financial supports from Guangdong Academy of Sciences Project(2018GDASCX-0402)of China,Yunnan Science and Technology Plan Project of China(2018IC080)the Natural Science Foundation of Hunan Province of China(2018JJ2524).
基金the National Natural Science Foundation of China(Nos.51771236,51901249,U1904216)the Science Fund for Distinguished Young Scholars of Hunan Province(No.2018JJ1038)。
文摘In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treatment.The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency.Ni/T-Nb_(2)O_(5)nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system,which provides effective buffering during the lithiation/delithiation process for cycling stability.The Ni/TNb_(2)O_(5)@CNFs show high surface area(26.321 m^(2)·g^(-1))and mesoporous microstructure,resulting in higher capacity and excellent rate performance.The Ni/T-Nb_(2)O_(5)@CNFs exhibit a remarkable capacity of 437 mAh·g^(-1)at a current density of0.5 A·g^(-1)after 230 cycles and a capacity of 173 mAh·g^(-1)at a current density up to 10.0 A·g^(-1)after 1400 cycles.This work indicates that nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs.
基金financially supported by the National Key Research and Development Program of China(No.2017YFB0306100)the National Natural Science Foundation of China(No.51771059)+2 种基金the Natural Science Foundation of Hunan Province(No.2018JJ2524)the International Scientific Technological Cooperation Projects of China(Nos.2015DFR50580 and 2013DFA31440)the Science and Technology Planning Project of Guangdong Province(No.2017A070701027)。
文摘Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs performances.The results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,respectively.The delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)layer.After 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)TBCs.The cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.
