Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme altern...Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.展开更多
Metal-organic frameworks(MOFs) are becoming more and more popular as the fillers in polymer electrolytes in recent years. In this study, a series of MOFs(NH_(2)-MIL-101(Fe), MIL-101(Fe), activated NH_(2)-MIL-101(Fe) a...Metal-organic frameworks(MOFs) are becoming more and more popular as the fillers in polymer electrolytes in recent years. In this study, a series of MOFs(NH_(2)-MIL-101(Fe), MIL-101(Fe), activated NH_(2)-MIL-101(Fe) and activated MIL-101(Fe)) were synthesized and added to PEO-based solid composite electrolytes(SCEs). Furthermore, the role of the —NH_(2) groups and open metal sites(OMSs) were both examined. Different ratios of MOFs vs polymers were also studied by the electrochemical characterizations. At last, we successfully designed a novel solid composite electrolyte containing activated NH_(2)-MIL-101(Fe),PEO, Li TFSI and PVDF for the high-performance all-solid-state lithium-metal batteries. This work might provide new insight to understand the interactions between polymers and functional groups or OMSs of MOFs better.展开更多
Savonius hydrokinetic turbine is a kind of turbine set which is suitable for low-velocity conditions.Unlike conventional turbines,Savonius turbines employ S-shaped blades and have simple internal structures.Therefore,...Savonius hydrokinetic turbine is a kind of turbine set which is suitable for low-velocity conditions.Unlike conventional turbines,Savonius turbines employ S-shaped blades and have simple internal structures.Therefore,there is a large space for optimizing the blade geometry.In this study,computational fluid dynamics(CFD)numerical simulation and genetic algorithm(GA)were used for the optimal design.The optimization strategies and methods were determined by comparing the results calculated by CFD with the experimental results.The weighted objective function was constructed with the maximum power coefficient Cp and the high-power coefficient range R under multiple working conditions.GA helps to find the optimal individual of the objective function.Compared the optimal scheme with the initial scheme,the overlap ratioβincreased from 0.2 to 0.202,and the clearance ratioεincreased from 0 to 0.179,the blade circumferential angleγincreased from 0°to 27°,the blade shape extended more towards the spindle.The overall power of Savonius turbines was maintained at a high level over 22%,R also increased from 0.73 to 1.02.In comparison with the initial scheme,the energy loss of the optimal scheme at high blade tip speed is greatly reduced,and this reduction is closely related to the optimization of blade geometry.As R becomes larger,Savonius turbines can adapt to the overall working conditions and meet the needs of its work in low flow rate conditions.The results of this paper can be used as a reference for the hydrodynamic optimization of Savonius turbine runners.展开更多
Comprehensive Summary This work systematically reviews recent progresses in the applications of MOF-derived materials modified 3D porous conductive framework as hosts for uniform lithium deposition in LMBs.A series of...Comprehensive Summary This work systematically reviews recent progresses in the applications of MOF-derived materials modified 3D porous conductive framework as hosts for uniform lithium deposition in LMBs.A series of commonly used lithiophilic materials and several kinds of representative MOF-derivation-modified 3D hosts as lithium metal anode(LMA)are presented.Finally,the challenges and future development of employing MOF-derived materials to modify the 3D porous conductive framework for LMA are included.展开更多
For several decades,the promise of implementing of lithium(Li)metal anodes for Li batteries has been a"holy grail"for researchers.Herein,we have proposed a facile design of a MOF-derived Co_(3)O_(4)nanoparti...For several decades,the promise of implementing of lithium(Li)metal anodes for Li batteries has been a"holy grail"for researchers.Herein,we have proposed a facile design of a MOF-derived Co_(3)O_(4)nanoparticles modified nickel foam,i.e.,Co_(3)O_(4)-NF,as a 3D host to achieve a uniform infusion of the molten Li.The molten Li was uniformly absorbed on the Co_(3)O_(4)-NF host only in 10 s due to its high Li lithiophilicity.The obtained Li-Co_(3)O_(4)-NF composite electrode shows high cycling stability in symmetric cells with low voltage hysteresis even at a high current density of 5 mA/cm2.The full cells of Li-Co_(3)O_(4)-NF/LiFePO_(4)can cycle for more than 500 cycles at 2C without obvious capacity decay.SEM after cycling and in situ optical microscope results suggest that the unique 3D host structure of the Li-Co_(3)O_(4)-NF anode plays key roles on suppressing the dendrite growth and decreasing the local current inhomogeneity.We believe this work might provide a new strategy for fabricating dendrite-free Li metal anodes and facilitate practical applications in Li batteries.展开更多
Molybdenum disulfide(Mo S_(2))has attracted great attention in hydrogen peroxide(H_(2)O_(2))activation as a Fenton-like catalyst and cocatalyst,but the distinct mechanism of generating^(·)OH remains unclear.In th...Molybdenum disulfide(Mo S_(2))has attracted great attention in hydrogen peroxide(H_(2)O_(2))activation as a Fenton-like catalyst and cocatalyst,but the distinct mechanism of generating^(·)OH remains unclear.In this paper,the metallic 1T phase and semiconducting 2H phase of Mo S_(2)nanosheets were prepared and applied in MoS_(2)/H_(2)O_(2)and MoS_(2)/Fe^(2+)/H_(2)O_(2)systems with and without light irradiation.Compared with2H-MoS_(2),1T-MoS_(2)exhibited superior removal rates in degrading organic pollutants in the two systems under light irradiation.However,the phase had little effect on activating H_(2)O_(2)in the Mo S_(2)/H_(2)O_(2)system under dark conditions.This is because it was difficult for the surface^(·)OH_(ads)generated in the Mo S_(2)/H_(2)O_(2)system to diffuse into solution,while the^(·)OH_(free)radicals were mainly responsible for degrading organic pollutants.When introducing light irradiation,external energy may accelerate the desorption of^(·)OH_(ads)into^(·)OH_(free.)Interestingly,the conversion between Mo^(4+)and Mo^(5+)triggered the decomposition of H_(2)O_(2)in the Fenton-like reaction,while the cycle of Mo^(4+)/Mo^(6+)promoted the regeneration of Fe^(3+)when employing 1T-MoS_(2)as a cocatalyst.Meanwhile,the 1T-MoS_(2)catalysts exhibited excellent stability and ability to degrade various organics in the two systems.This work offers deeper insight into the Mo S_(2)-based Fenton-like and cocatalytic mechanisms.展开更多
基金the National Natural Science Foundation of China(Nos.52272046,52090030,52090031,52122301,51973191)the Natural Science Foundation of Zhejiang Province(LR23E020003)+4 种基金Shanxi-Zheda Institute of New Materials and Chemical Engineering(2021SZ-FR004,2022SZ-TD011,2022SZ-TD012,2022SZ-TD014)Hundred Talents Program of Zhejiang University(188020*194231701/113,112300+1944223R3/003,112300+1944223R3/004)the Fundamental Research Funds for the Central Universities(Nos.226-2023-00023,226-2023-00082,2021FZZX001-17,K20200060)National Key R&D Program of China(NO.2022YFA1205300,NO.2022YFA1205301,NO.2020YFF0204400,NO.2022YFF0609801)“Pioneer”and“Leading Goose”R&D Program of Zhejiang 2023C01190.
文摘Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.
基金financially supported by National Natural Science Foundation of China (21701083)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_3137)。
文摘Metal-organic frameworks(MOFs) are becoming more and more popular as the fillers in polymer electrolytes in recent years. In this study, a series of MOFs(NH_(2)-MIL-101(Fe), MIL-101(Fe), activated NH_(2)-MIL-101(Fe) and activated MIL-101(Fe)) were synthesized and added to PEO-based solid composite electrolytes(SCEs). Furthermore, the role of the —NH_(2) groups and open metal sites(OMSs) were both examined. Different ratios of MOFs vs polymers were also studied by the electrochemical characterizations. At last, we successfully designed a novel solid composite electrolyte containing activated NH_(2)-MIL-101(Fe),PEO, Li TFSI and PVDF for the high-performance all-solid-state lithium-metal batteries. This work might provide new insight to understand the interactions between polymers and functional groups or OMSs of MOFs better.
基金funded by National Natural Science Foundation of China,Grant Number 52079142.
文摘Savonius hydrokinetic turbine is a kind of turbine set which is suitable for low-velocity conditions.Unlike conventional turbines,Savonius turbines employ S-shaped blades and have simple internal structures.Therefore,there is a large space for optimizing the blade geometry.In this study,computational fluid dynamics(CFD)numerical simulation and genetic algorithm(GA)were used for the optimal design.The optimization strategies and methods were determined by comparing the results calculated by CFD with the experimental results.The weighted objective function was constructed with the maximum power coefficient Cp and the high-power coefficient range R under multiple working conditions.GA helps to find the optimal individual of the objective function.Compared the optimal scheme with the initial scheme,the overlap ratioβincreased from 0.2 to 0.202,and the clearance ratioεincreased from 0 to 0.179,the blade circumferential angleγincreased from 0°to 27°,the blade shape extended more towards the spindle.The overall power of Savonius turbines was maintained at a high level over 22%,R also increased from 0.73 to 1.02.In comparison with the initial scheme,the energy loss of the optimal scheme at high blade tip speed is greatly reduced,and this reduction is closely related to the optimization of blade geometry.As R becomes larger,Savonius turbines can adapt to the overall working conditions and meet the needs of its work in low flow rate conditions.The results of this paper can be used as a reference for the hydrodynamic optimization of Savonius turbine runners.
基金the National Natural Science Foundation of China(Nos.21701083 and 22179054).
文摘Comprehensive Summary This work systematically reviews recent progresses in the applications of MOF-derived materials modified 3D porous conductive framework as hosts for uniform lithium deposition in LMBs.A series of commonly used lithiophilic materials and several kinds of representative MOF-derivation-modified 3D hosts as lithium metal anode(LMA)are presented.Finally,the challenges and future development of employing MOF-derived materials to modify the 3D porous conductive framework for LMA are included.
基金This work was financially supported by National Natural Science Foundation of China(No.21701083)Fok Ying-Tong Education Foundation of China(No.171064)Natural Science Foundation of Hebei Province(Nos.B2022203018,B2018203297).
文摘For several decades,the promise of implementing of lithium(Li)metal anodes for Li batteries has been a"holy grail"for researchers.Herein,we have proposed a facile design of a MOF-derived Co_(3)O_(4)nanoparticles modified nickel foam,i.e.,Co_(3)O_(4)-NF,as a 3D host to achieve a uniform infusion of the molten Li.The molten Li was uniformly absorbed on the Co_(3)O_(4)-NF host only in 10 s due to its high Li lithiophilicity.The obtained Li-Co_(3)O_(4)-NF composite electrode shows high cycling stability in symmetric cells with low voltage hysteresis even at a high current density of 5 mA/cm2.The full cells of Li-Co_(3)O_(4)-NF/LiFePO_(4)can cycle for more than 500 cycles at 2C without obvious capacity decay.SEM after cycling and in situ optical microscope results suggest that the unique 3D host structure of the Li-Co_(3)O_(4)-NF anode plays key roles on suppressing the dendrite growth and decreasing the local current inhomogeneity.We believe this work might provide a new strategy for fabricating dendrite-free Li metal anodes and facilitate practical applications in Li batteries.
基金financially supported by the Natural Science Foundation of Henan Province(No.212300410336)Program for Science and Technology Innovation Talent in Universities of Henan Province(No.20HASTIT016)National Natural Science Foundation of China(No.51902101)。
文摘Molybdenum disulfide(Mo S_(2))has attracted great attention in hydrogen peroxide(H_(2)O_(2))activation as a Fenton-like catalyst and cocatalyst,but the distinct mechanism of generating^(·)OH remains unclear.In this paper,the metallic 1T phase and semiconducting 2H phase of Mo S_(2)nanosheets were prepared and applied in MoS_(2)/H_(2)O_(2)and MoS_(2)/Fe^(2+)/H_(2)O_(2)systems with and without light irradiation.Compared with2H-MoS_(2),1T-MoS_(2)exhibited superior removal rates in degrading organic pollutants in the two systems under light irradiation.However,the phase had little effect on activating H_(2)O_(2)in the Mo S_(2)/H_(2)O_(2)system under dark conditions.This is because it was difficult for the surface^(·)OH_(ads)generated in the Mo S_(2)/H_(2)O_(2)system to diffuse into solution,while the^(·)OH_(free)radicals were mainly responsible for degrading organic pollutants.When introducing light irradiation,external energy may accelerate the desorption of^(·)OH_(ads)into^(·)OH_(free.)Interestingly,the conversion between Mo^(4+)and Mo^(5+)triggered the decomposition of H_(2)O_(2)in the Fenton-like reaction,while the cycle of Mo^(4+)/Mo^(6+)promoted the regeneration of Fe^(3+)when employing 1T-MoS_(2)as a cocatalyst.Meanwhile,the 1T-MoS_(2)catalysts exhibited excellent stability and ability to degrade various organics in the two systems.This work offers deeper insight into the Mo S_(2)-based Fenton-like and cocatalytic mechanisms.
基金We are grateful to the National Natural Science Foundation of China （Grant No. 21402094, 41401258）, the Natural Science Foundation of Jiangsu Province （Grant No. BK20140678, BK20131044） and the Fun- damental Research Funds for the Central Universities （Grant No. KJQN201551）.
