All-solid-state lithium batteries(ASSLBs)based on sulfide electrolytes promise next-generation energy storage with high energy density and safety.However,the sulfide electrolytes suffer from phase instability and slug...All-solid-state lithium batteries(ASSLBs)based on sulfide electrolytes promise next-generation energy storage with high energy density and safety.However,the sulfide electrolytes suffer from phase instability and sluggish interfacial charge transport when pairing with layered oxide cathodes at high voltages.Herein,a simple and efficient strategy is proposed using two-dimensional Ti_(3)C_(2)T_(x)MXene as starting material to in-situ construct a 15 nm Li_(2)TiO_(3) layer on a typical oxide cathode,LiCoO_(2).The in-situ transformation of Ti_(3)C_(2)T_(x)into Li_(2)TiO_(3) layer occurs at a low temperature of 500℃,avoiding the phase deterioration of LiCoO_(2).The thin Li_(2)TiO_(3) layer is Li^(+)conducting and electrochemically stable,thereby preventing the interfacial decomposition of sulfide electrolytes induced by LiCoO_(2) at high voltages and facilitating Li+transport at the interface.Moreover,Li_(2)TiO_(3) can stabilize the layer structure of LiCoO_(2) at high voltages.Consequently,the sulfide-based ASSLB using LiCoO_(2)@Li_(2)TiO_(3) cathode can operate stably at a high voltage of up to 4.5 V(vs.Li+/Li),delivering an outstanding initial specific discharge capacity of 138.8 m Ah/g with a high capacity retention of 86.2% after 100 cycles at 0.2 C.The in-situ transformation strategy may also apply to other MXenes,offering a general approach for constructing other advanced lithiated coatings for oxide cathodes.展开更多
Transitional metal oxides(TMOs)are important functional materials in silicon-based and thin-film optoelectronics.Here,TMOs areapplied in carbon nanotube(CNT)-Si solar cells by spin-coating solutions of metal chlorides...Transitional metal oxides(TMOs)are important functional materials in silicon-based and thin-film optoelectronics.Here,TMOs areapplied in carbon nanotube(CNT)-Si solar cells by spin-coating solutions of metal chlorides that undergo favorable transformation in ambient conditions.An unconventional change in solar cell behavior is observed after coating two particular chlorides(MoCl,and WCls,respectively),characterized by an initial severe degradation followed by gradual recovery and then well surpassing the original performance.Detailed analysis reveals that the formation of correspondina oxides(MoOa and WO.)enables two primary functions on both CNTs(p-type doping)and Si(inducing inversion layer),leading to significant improvement in open-circuit voltage and fill factor,with power conversion efficiencies up to 13.0%(MoOg)and 13.4%(WOg).Further combining with other chlorides to increase the short-circuit current,ultimate cells efficiencies achieve>16%with over 90%retention after 24 h,which are among the highes stable efficiencies reported for CNT-Si solar cells.The transformation of functional layers as demonstrated here has profoundinfluence on the device characteristics,and represents a potential strategy in low-cost manufacturing of next-generation high efficiency photovoltaics.展开更多
Topochemical transformation has emerged as a promising method for fabricating two-dimensional (2D) materials with precise control over their composition and morphology. However, the large-scale synthesis of ultrathin ...Topochemical transformation has emerged as a promising method for fabricating two-dimensional (2D) materials with precise control over their composition and morphology. However, the large-scale synthesis of ultrathin 2D materials with controllable thickness remains a tremendous challenge. Herein, we adopt an efficient topochemical synthesis strategy, employing a confined reaction space to fabricate ultrathin 2D Sn_(4)P_(3) nanosheets in large-scale. By carefully adjusting the rolling number during the processing of Sn/Al foils, we have successfully fabricated Sn_(4)P_(3) nanosheets with varied layer thicknesses, achieving a remarkable minimum thickness of two layers (~ 2.2 nm). Remarkably, the bilayer Sn_(4)P_(3) nanosheets display an exceptional initial capacity of 1088 mAh·g^(−1), nearing the theoretical value of 1230 mAh·g^(−1). Furthermore, we reveal their high-rate property as well as outstanding cyclic stability, maintaining capacity without fading more than 3000 cycles. By precisely controlling the layer thickness and ensuring nanoscale uniformity, we enhance the lithium cycling performance of Sn_(4)P_(3), marking a significant advancement in developing high-performance energy storage systems.展开更多
The steady two-dimensional magnetohydrodynamic stagnation flow towards a nonlinear stretching surface is studied. The no-slip condition on the solid boundary is replaced with a partial slip condition. A scaling group ...The steady two-dimensional magnetohydrodynamic stagnation flow towards a nonlinear stretching surface is studied. The no-slip condition on the solid boundary is replaced with a partial slip condition. A scaling group transformation is used to get the invariants. Using the invariants, a third-order ordinary differential equation corresponding to the momentum is obtained. An analytical solution is obtained in a series form using a homotopy analysis method. Reliability and efficiency of series solutions are shown by the good agreement with numerical results presented in the literature. The effects of the slip parameter, the magnetic field parameter, the velocity ratio parameter, the suction velocity parameter, and the power law exponent on the flow are investigated. The results show that the velocity and shear stress profiles are greatly influenced by these parameters.展开更多
"Natural forces" ——core theory of Fenlong technique is explored in this paper. We break through key core technique of farming and agriculture,and invent new method of Fenlong tillage. Broad-spectrum Fenlon..."Natural forces" ——core theory of Fenlong technique is explored in this paper. We break through key core technique of farming and agriculture,and invent new method of Fenlong tillage. Broad-spectrum Fenlong tillage technique system based on "full-layer and bottom-layer superdeep tillage without disturbance of soil layer" is established,which provides the possibility for establishing "modern Fenlong agriculture". When applied in 35 kinds of crops in 24 provinces of China,yield could be increased by 10%-50%,and even 1 times. In the transformation of severe saline-alkali land,corn yield could increase by 73. 0%,and Na,Cl and Mg ions in grain decrease by 20. 81%,1. 47%,and 9. 36% respectively. The newly developed "scarification tillage( reclamation) in the bottom area" could cover "bottom tillage" of dryland,paddy field,degraded grassland,perennial sugarcane,forest and fruit land,traditional Chinese medicine land,and ecological reconstruction of desertification land. It is point out that if Fenlong technique is used in 666 666. 67 km2 of farmland,200 000 km2 of saline-alkali land,666 666. 67 km2 of degraded grassland,and fisheries in rivers and offshore waters are used,trillion yuan of Fenlong economy could be formed,and the nationals will walk towards a healthier new era.Fenlong technique involves agriculture,forestry,water,grass,environment and other aspects,and its global promotion could improve eco-environment and change world development pattern.展开更多
Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the p...Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the properties (coercive field, critical thickness) of a ferroelectric thin film. Our theoretical results show that the surface layer is likely to answer for the emergence of phase transformation.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.52201242,52250010)Natural Science Foundation of Jiangsu Province(Nos.BK20200386,BK20200186)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2021QNRC001)the Fundamental Research Funds for the Central Universities(No.2242022R40018)。
文摘All-solid-state lithium batteries(ASSLBs)based on sulfide electrolytes promise next-generation energy storage with high energy density and safety.However,the sulfide electrolytes suffer from phase instability and sluggish interfacial charge transport when pairing with layered oxide cathodes at high voltages.Herein,a simple and efficient strategy is proposed using two-dimensional Ti_(3)C_(2)T_(x)MXene as starting material to in-situ construct a 15 nm Li_(2)TiO_(3) layer on a typical oxide cathode,LiCoO_(2).The in-situ transformation of Ti_(3)C_(2)T_(x)into Li_(2)TiO_(3) layer occurs at a low temperature of 500℃,avoiding the phase deterioration of LiCoO_(2).The thin Li_(2)TiO_(3) layer is Li^(+)conducting and electrochemically stable,thereby preventing the interfacial decomposition of sulfide electrolytes induced by LiCoO_(2) at high voltages and facilitating Li+transport at the interface.Moreover,Li_(2)TiO_(3) can stabilize the layer structure of LiCoO_(2) at high voltages.Consequently,the sulfide-based ASSLB using LiCoO_(2)@Li_(2)TiO_(3) cathode can operate stably at a high voltage of up to 4.5 V(vs.Li+/Li),delivering an outstanding initial specific discharge capacity of 138.8 m Ah/g with a high capacity retention of 86.2% after 100 cycles at 0.2 C.The in-situ transformation strategy may also apply to other MXenes,offering a general approach for constructing other advanced lithiated coatings for oxide cathodes.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(No.51672005).
文摘Transitional metal oxides(TMOs)are important functional materials in silicon-based and thin-film optoelectronics.Here,TMOs areapplied in carbon nanotube(CNT)-Si solar cells by spin-coating solutions of metal chlorides that undergo favorable transformation in ambient conditions.An unconventional change in solar cell behavior is observed after coating two particular chlorides(MoCl,and WCls,respectively),characterized by an initial severe degradation followed by gradual recovery and then well surpassing the original performance.Detailed analysis reveals that the formation of correspondina oxides(MoOa and WO.)enables two primary functions on both CNTs(p-type doping)and Si(inducing inversion layer),leading to significant improvement in open-circuit voltage and fill factor,with power conversion efficiencies up to 13.0%(MoOg)and 13.4%(WOg).Further combining with other chlorides to increase the short-circuit current,ultimate cells efficiencies achieve>16%with over 90%retention after 24 h,which are among the highes stable efficiencies reported for CNT-Si solar cells.The transformation of functional layers as demonstrated here has profoundinfluence on the device characteristics,and represents a potential strategy in low-cost manufacturing of next-generation high efficiency photovoltaics.
基金supported partially by project of the National Natural Science Foundation of China(Nos.52102203 and 51972110)Beijing Science and Technology Project(No.Z211100004621010)+4 种基金Beijing Natural Science Foundation(No.2222076)State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(No.LAPS202114)Huaneng Group Headquarters Science and Technology Project(No.HNKJ20-H88)2022 Strategic Research Key Project of Science and Technology Commission of the Ministry of Education,the Fundamental Research Funds for the Central Universities(No.2024MS082)the NCEPU “Double First- Class” Program.
文摘Topochemical transformation has emerged as a promising method for fabricating two-dimensional (2D) materials with precise control over their composition and morphology. However, the large-scale synthesis of ultrathin 2D materials with controllable thickness remains a tremendous challenge. Herein, we adopt an efficient topochemical synthesis strategy, employing a confined reaction space to fabricate ultrathin 2D Sn_(4)P_(3) nanosheets in large-scale. By carefully adjusting the rolling number during the processing of Sn/Al foils, we have successfully fabricated Sn_(4)P_(3) nanosheets with varied layer thicknesses, achieving a remarkable minimum thickness of two layers (~ 2.2 nm). Remarkably, the bilayer Sn_(4)P_(3) nanosheets display an exceptional initial capacity of 1088 mAh·g^(−1), nearing the theoretical value of 1230 mAh·g^(−1). Furthermore, we reveal their high-rate property as well as outstanding cyclic stability, maintaining capacity without fading more than 3000 cycles. By precisely controlling the layer thickness and ensuring nanoscale uniformity, we enhance the lithium cycling performance of Sn_(4)P_(3), marking a significant advancement in developing high-performance energy storage systems.
基金Project supported by the National Natural Science Foundation of China (No. 50936003)the Open Project of State Key Laboratory for Advanced Metals and Materials and the Research Foundation of Engineering Research Institute of University of Science and Technology Beijing (No. 2009Z-02)
文摘The steady two-dimensional magnetohydrodynamic stagnation flow towards a nonlinear stretching surface is studied. The no-slip condition on the solid boundary is replaced with a partial slip condition. A scaling group transformation is used to get the invariants. Using the invariants, a third-order ordinary differential equation corresponding to the momentum is obtained. An analytical solution is obtained in a series form using a homotopy analysis method. Reliability and efficiency of series solutions are shown by the good agreement with numerical results presented in the literature. The effects of the slip parameter, the magnetic field parameter, the velocity ratio parameter, the suction velocity parameter, and the power law exponent on the flow are investigated. The results show that the velocity and shear stress profiles are greatly influenced by these parameters.
基金Supported by Science and Technology Major Project of Guangxi(Guike AA17204037)
文摘"Natural forces" ——core theory of Fenlong technique is explored in this paper. We break through key core technique of farming and agriculture,and invent new method of Fenlong tillage. Broad-spectrum Fenlong tillage technique system based on "full-layer and bottom-layer superdeep tillage without disturbance of soil layer" is established,which provides the possibility for establishing "modern Fenlong agriculture". When applied in 35 kinds of crops in 24 provinces of China,yield could be increased by 10%-50%,and even 1 times. In the transformation of severe saline-alkali land,corn yield could increase by 73. 0%,and Na,Cl and Mg ions in grain decrease by 20. 81%,1. 47%,and 9. 36% respectively. The newly developed "scarification tillage( reclamation) in the bottom area" could cover "bottom tillage" of dryland,paddy field,degraded grassland,perennial sugarcane,forest and fruit land,traditional Chinese medicine land,and ecological reconstruction of desertification land. It is point out that if Fenlong technique is used in 666 666. 67 km2 of farmland,200 000 km2 of saline-alkali land,666 666. 67 km2 of degraded grassland,and fisheries in rivers and offshore waters are used,trillion yuan of Fenlong economy could be formed,and the nationals will walk towards a healthier new era.Fenlong technique involves agriculture,forestry,water,grass,environment and other aspects,and its global promotion could improve eco-environment and change world development pattern.
文摘Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the properties (coercive field, critical thickness) of a ferroelectric thin film. Our theoretical results show that the surface layer is likely to answer for the emergence of phase transformation.
