Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,〈001〉-textured Na0.7Bi0.1NbO3(NBN)ceramics were prepared by a templated grain growth...Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,〈001〉-textured Na0.7Bi0.1NbO3(NBN)ceramics were prepared by a templated grain growth technique.The effects of microstructure and orientation degree on dielectric properties,polarization and energy storage performance were investigated.The textured ceramic with an optimized orientation degree(70%)showed a high Wrec of 2.4 J/cm3 andηof 85.6%.The excellent energy storage properties of textured ceramic originate from the co-effect of interfacial polarization and clamping effect.The results indicate that texture development is a potential candidate to optimize the energy storage properties of functional ceramics.展开更多
The Gibbs free energies of reaction △rGτ of KNbO3 and NaNbO3 were calculated and then that of KxNa1-xNbO3 was estimated. On the basis of the thermodynamic calculation results, the hydrothermal temperatures were desi...The Gibbs free energies of reaction △rGτ of KNbO3 and NaNbO3 were calculated and then that of KxNa1-xNbO3 was estimated. On the basis of the thermodynamic calculation results, the hydrothermal temperatures were designed at 100, 160, and 230℃ respectively. However, NaNbO3 was prepared when the heating temperature was higher than 160℃, and KNbO3 and KxNa1-xNbO3 were obtained at 230℃, suggesting that only at a higher temperature the kinetic requirement is satisfied. According to the X-ray diffraction results, both the solid solutions, NaNbO3-based solid solution, Na1-xKxNbO3, and KNbO3-based solid solution, K1-xNaxNbO3, were hydrothermally synthesized in 6 mol/L alkali （NaOH and KOH） solution at 230℃.展开更多
A new intercalation-type anode material is reported herein to improve the lithium storage kinetics for high-rate lithium ion capacitors.The crystal structure of orthorhombic NaNbO3 indicates two possible tunnels for l...A new intercalation-type anode material is reported herein to improve the lithium storage kinetics for high-rate lithium ion capacitors.The crystal structure of orthorhombic NaNbO3 indicates two possible tunnels for lithium ions insertion into NaNbO3 host along the<101>and<141>directions.Moreover,in situ XRD is conducted to investigate the lithium storage mechanism and structural evolution of the NaNb O_(3) anode,demonstrating its intercalation behavior through(101)and(141)planes.Furthermore,the rGO nanosheets are introduced to facilitate the charge transfer,which also effectively prevent the aggregation of NaNbO3 nanocubes.As expected,the NaNbO_(3)/rGO nanocomposites possess remarkable reversible capacity(465 mA h g^(-1) at 0.1 A g^(-1)),superior rate capability(325 mA h g^(-1) at 1.0 A g^(-1))and cycling stability,attributed to their synergistic effect and high Li+diffusion coefficient DLi[D(NaNbO_(3)/rGO)/D(NaNbO_(3))≈31.54].Remarkably,the NaNbO3/rGO-based LIC delivers a high energy density of 166.7 W h kg^(-1) at 112.4 W kg^(-1) and remains 24.1 W h kg^(-1) at an ultrahigh power density of26621.2 W kg^(-1),with an outstanding cycling durability(90%retention over 3000 cycles at 1.0 A g^(-1)).This study provides new insights on novel intercalation-type anode material to enrich the materials system of LICs.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52072080 and 11864004)the Guangxi Natural Science Fund for Distinguished Young Scholars(Grant No.2022GXNSFFA035034).
文摘Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,〈001〉-textured Na0.7Bi0.1NbO3(NBN)ceramics were prepared by a templated grain growth technique.The effects of microstructure and orientation degree on dielectric properties,polarization and energy storage performance were investigated.The textured ceramic with an optimized orientation degree(70%)showed a high Wrec of 2.4 J/cm3 andηof 85.6%.The excellent energy storage properties of textured ceramic originate from the co-effect of interfacial polarization and clamping effect.The results indicate that texture development is a potential candidate to optimize the energy storage properties of functional ceramics.
基金supported by the National Science Funds for Creative Research Groups of China(51421006)the National Science Fundation of China for Excellent Young Scholars(51422902)+3 种基金the Key Program of National Natural Science Foundation of China(41430751)the National Natural Science Foundation of China(51679063)the National Key Plan for Research and Development of China(2016YFC0502203)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)~~
基金the National Natural Science Foundation of China (Nos. 50425415, 50402022, and 50672006)
文摘The Gibbs free energies of reaction △rGτ of KNbO3 and NaNbO3 were calculated and then that of KxNa1-xNbO3 was estimated. On the basis of the thermodynamic calculation results, the hydrothermal temperatures were designed at 100, 160, and 230℃ respectively. However, NaNbO3 was prepared when the heating temperature was higher than 160℃, and KNbO3 and KxNa1-xNbO3 were obtained at 230℃, suggesting that only at a higher temperature the kinetic requirement is satisfied. According to the X-ray diffraction results, both the solid solutions, NaNbO3-based solid solution, Na1-xKxNbO3, and KNbO3-based solid solution, K1-xNaxNbO3, were hydrothermally synthesized in 6 mol/L alkali （NaOH and KOH） solution at 230℃.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20170549)the National Natural Science Foundation of China(No.21706103)Postdoctoral Science Foundation of Jiangsu Province(No.2019K295)。
文摘A new intercalation-type anode material is reported herein to improve the lithium storage kinetics for high-rate lithium ion capacitors.The crystal structure of orthorhombic NaNbO3 indicates two possible tunnels for lithium ions insertion into NaNbO3 host along the<101>and<141>directions.Moreover,in situ XRD is conducted to investigate the lithium storage mechanism and structural evolution of the NaNb O_(3) anode,demonstrating its intercalation behavior through(101)and(141)planes.Furthermore,the rGO nanosheets are introduced to facilitate the charge transfer,which also effectively prevent the aggregation of NaNbO3 nanocubes.As expected,the NaNbO_(3)/rGO nanocomposites possess remarkable reversible capacity(465 mA h g^(-1) at 0.1 A g^(-1)),superior rate capability(325 mA h g^(-1) at 1.0 A g^(-1))and cycling stability,attributed to their synergistic effect and high Li+diffusion coefficient DLi[D(NaNbO_(3)/rGO)/D(NaNbO_(3))≈31.54].Remarkably,the NaNbO3/rGO-based LIC delivers a high energy density of 166.7 W h kg^(-1) at 112.4 W kg^(-1) and remains 24.1 W h kg^(-1) at an ultrahigh power density of26621.2 W kg^(-1),with an outstanding cycling durability(90%retention over 3000 cycles at 1.0 A g^(-1)).This study provides new insights on novel intercalation-type anode material to enrich the materials system of LICs.
