As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities...As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.展开更多
We present a detailed investigation of magnetic properties of colossal magnetoresistance material HgCr2Se4. While spontaneous magnetization and zero-field magnetic susceptibility are found to follow asymptotic scaling...We present a detailed investigation of magnetic properties of colossal magnetoresistance material HgCr2Se4. While spontaneous magnetization and zero-field magnetic susceptibility are found to follow asymptotic scaling laws for a narrow range of temperatures near the critical point, two methods with connections to the renormalization group theory provide analytical descriptions of the magnetic properties for much wider temperature ranges. Based on this, an analytical formula is obtained for the temperature dependence of the low field magnetoresistance in the paramagnetic phase.展开更多
The effect of an external magnetic field on the structural and magnetic properties of bond frustrated ZnCr2 Se4 at low temperatures is investigated using magnetization, dielectric constants and thermal conductivity ex...The effect of an external magnetic field on the structural and magnetic properties of bond frustrated ZnCr2 Se4 at low temperatures is investigated using magnetization, dielectric constants and thermal conductivity experiments. With an increase in the magnetic field H, the antiferromagnetic transition temperature TN is observed to shift progressively toward lower temperatures. The corresponding high temperature cubic （Fd3m） to low temperature tetragonal （I41amd） structural transition is tuned simultaneously due to the inherent strong spin-lattice coupling. In the antiferromagnetic phase, an anomaly at Hc2 defined as a steep downward peak in the derivative of the M-H curve is dearly drawn. It is found that TN versus H and Hc2 versus T exhibit a consistent tendency, indicative of a field-induced tetragonal （I41amd） to cubic （Fd3m） structural transition. The transition is further substantiated by the field-dependent dielectric constant and thermal conductivity measurements. We modify the T-H phase diagram, highlighting the coexistence of the paramagnetic state and ferromagnetic clusters between 100K and TN.展开更多
基金financially supported by the Natural Science Foundation of Hebei Province of China(Nos.E2021202011 and E2018202123)Jian-Hua Research Foundation of Hebei University of Technology(No.HB1921)+4 种基金High-strength,Highprecision,Superconducting Rail Transit Aluminum Research and Development and Industrialization Projects(No.2019TSLH0110)"One Belt,One Road"Technology Innovation Cooperation Project of Tianjin(No.18PTZWHZ00220)Ministry of Science and Higher Education of the Russian Federation as part of World-class Research Center program(No.075-15-2020-934)Foundation of Strengthening Program(No.2019-JCJQ-142-00)the Exchange Project of the Third Meeting of the Science and Technology Cooperation Subcommittee of the China-Ukraine Intergovernmental Cooperation Committee(No.CU03-11).
文摘As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61425015,11474330 and 11374337the National Basic Research Program of China under Grant Nos 2012CB921703 and 2015CB921102the Chinese Academy of Sciences
文摘We present a detailed investigation of magnetic properties of colossal magnetoresistance material HgCr2Se4. While spontaneous magnetization and zero-field magnetic susceptibility are found to follow asymptotic scaling laws for a narrow range of temperatures near the critical point, two methods with connections to the renormalization group theory provide analytical descriptions of the magnetic properties for much wider temperature ranges. Based on this, an analytical formula is obtained for the temperature dependence of the low field magnetoresistance in the paramagnetic phase.
基金Supported by the National Basic Research Program of China under Grant No 2011CBA00111the National Natural Science Foundation of China under Grant No U1332143
文摘The effect of an external magnetic field on the structural and magnetic properties of bond frustrated ZnCr2 Se4 at low temperatures is investigated using magnetization, dielectric constants and thermal conductivity experiments. With an increase in the magnetic field H, the antiferromagnetic transition temperature TN is observed to shift progressively toward lower temperatures. The corresponding high temperature cubic （Fd3m） to low temperature tetragonal （I41amd） structural transition is tuned simultaneously due to the inherent strong spin-lattice coupling. In the antiferromagnetic phase, an anomaly at Hc2 defined as a steep downward peak in the derivative of the M-H curve is dearly drawn. It is found that TN versus H and Hc2 versus T exhibit a consistent tendency, indicative of a field-induced tetragonal （I41amd） to cubic （Fd3m） structural transition. The transition is further substantiated by the field-dependent dielectric constant and thermal conductivity measurements. We modify the T-H phase diagram, highlighting the coexistence of the paramagnetic state and ferromagnetic clusters between 100K and TN.
