The sulfur cathodes operating via solid phase conversion of sulfur have natural advantages in suppressing polysulfide dissolution and lowering the electrolyte dosage,and thus realizing significant improvements in both...The sulfur cathodes operating via solid phase conversion of sulfur have natural advantages in suppressing polysulfide dissolution and lowering the electrolyte dosage,and thus realizing significant improvements in both cycle life and energy density.To realize an ideal solid-phase conversion of sulfur,a deep understanding of the regulation path of reaction mechanism and a corresponding intentional material and/or cathode design are highly essential.Herein,via covalently fixing of sulfur onto the triallyl isocyanurate,a series of S-triallyl isocyanurate organosulfur polymer composites(STIs) are developed.Relationship between the structure and the electrochemical conversion behavior of STIs is systematically investigated.It is found that the structure of STIs varies with the synthetic temperature,and correspondingly the electrochemical redox of sulfur can be controlled from conventional "solid-liquid-solid" conversion to the "solid-solid" one.Among the STI series,the STI-5 composite realizes an ideal solid-phase conversion and demonstrates great potential for building a Li-S battery with high-energy density and long-cyclelife:it realizes stable cycling over 1000 cycles in carbonate electrolyte,with a degradation rate of0.053% per cycle;the corresponding pouch cell shows almost no capacity decay for 125 cycles under the conditions of high sulfur loading(4.5 mg cm^(-2)) and lean electrolyte(8 μL mg_s^(-1)).In addition,the tailoring strategy of STI can also apply to other precursors with allyl functional groups to develop new organosulfur polymers for "solid-solid" sulfur cathodes.The vulcanized triallyl phosphate(STP) and triallylamine(STA) both show great lithium storage potential.This strategy successfully develops a new family of organosulfur polymers as cathodes for Li-S batteries via solid-phase conversion of sulfur,and brings insights to the mechanism study in Li-S batteries.展开更多
This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Str...This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Strong concentration polarization was found for the modules with big membrane bundles. The concentration polarization was enhanced at high temperature due to the higher water permeation flux. The increase of feed flow could improve water permeation flux for the membrane modules with small membrane bundle.Computational fluid dynamics was used to visualize the flow field distribution inside of the modules with different configurations. The membrane module with seven bundles exhibited highest separation efficiency due to the uniform distribution of flow rate. The packing density could be 10 times higher than that of the tubular membrane module. The hollow fiber membrane module exhibited good stability for ethanol dehydration.展开更多
A new scalable approach is reported here for producing the polyelectrolyte complex(PEC)fiber of alginate(ALG)and poly(diallyldimethylammonium chloride)(PDDA).Salt(LiBr,NaBr,or KBr)is used to restrict the complexation ...A new scalable approach is reported here for producing the polyelectrolyte complex(PEC)fiber of alginate(ALG)and poly(diallyldimethylammonium chloride)(PDDA).Salt(LiBr,NaBr,or KBr)is used to restrict the complexation of negatively charged ALG and positively charged PDDA in solution to obtain spinnable fluid that can be directly extruded into the coagulation bath to form nascent fiber.A water washing step is adopted right after the formation of nascent fiber to eliminate the defects in fiber.Morphology and mechanical properties of the as-prepared ALG/PDDA complex fiber are found to be greatly affected by the water washing,as well as the amount and the type of salt used.As the reported approach is similar to the wet-spinning process which is a commonly used method for industrial production of fibers,it is promising to be applied in larger scale production of PEC fibers.展开更多
基金supported by the National Science Foundation of China (22075091)the National Science Foundation of Hubei Province (2021CFA066)。
文摘The sulfur cathodes operating via solid phase conversion of sulfur have natural advantages in suppressing polysulfide dissolution and lowering the electrolyte dosage,and thus realizing significant improvements in both cycle life and energy density.To realize an ideal solid-phase conversion of sulfur,a deep understanding of the regulation path of reaction mechanism and a corresponding intentional material and/or cathode design are highly essential.Herein,via covalently fixing of sulfur onto the triallyl isocyanurate,a series of S-triallyl isocyanurate organosulfur polymer composites(STIs) are developed.Relationship between the structure and the electrochemical conversion behavior of STIs is systematically investigated.It is found that the structure of STIs varies with the synthetic temperature,and correspondingly the electrochemical redox of sulfur can be controlled from conventional "solid-liquid-solid" conversion to the "solid-solid" one.Among the STI series,the STI-5 composite realizes an ideal solid-phase conversion and demonstrates great potential for building a Li-S battery with high-energy density and long-cyclelife:it realizes stable cycling over 1000 cycles in carbonate electrolyte,with a degradation rate of0.053% per cycle;the corresponding pouch cell shows almost no capacity decay for 125 cycles under the conditions of high sulfur loading(4.5 mg cm^(-2)) and lean electrolyte(8 μL mg_s^(-1)).In addition,the tailoring strategy of STI can also apply to other precursors with allyl functional groups to develop new organosulfur polymers for "solid-solid" sulfur cathodes.The vulcanized triallyl phosphate(STP) and triallylamine(STA) both show great lithium storage potential.This strategy successfully develops a new family of organosulfur polymers as cathodes for Li-S batteries via solid-phase conversion of sulfur,and brings insights to the mechanism study in Li-S batteries.
基金Supported by the National Natural Science Foundation of China(21222602,21490585 and 21176117)National High-tech R&D Program of China(2015AA03A602)+4 种基金the Key Project of Chinese Ministry of Education(212060)the Outstanding Young Fund of Jiangsu Province(BK2012040)Young Fund of Jiangsu Province(BK20130915)the "Six Top Talents" and "333 Talent Project" of Jiangsu Province,a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Innovation Project for Graduate Student of Jiangsu Province(KYLX15-0790)
文摘This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Strong concentration polarization was found for the modules with big membrane bundles. The concentration polarization was enhanced at high temperature due to the higher water permeation flux. The increase of feed flow could improve water permeation flux for the membrane modules with small membrane bundle.Computational fluid dynamics was used to visualize the flow field distribution inside of the modules with different configurations. The membrane module with seven bundles exhibited highest separation efficiency due to the uniform distribution of flow rate. The packing density could be 10 times higher than that of the tubular membrane module. The hollow fiber membrane module exhibited good stability for ethanol dehydration.
基金supported by the National Natural Science Foundation of China(No.51973029)the Fundamen-tal Research Funds for the Central University.
文摘A new scalable approach is reported here for producing the polyelectrolyte complex(PEC)fiber of alginate(ALG)and poly(diallyldimethylammonium chloride)(PDDA).Salt(LiBr,NaBr,or KBr)is used to restrict the complexation of negatively charged ALG and positively charged PDDA in solution to obtain spinnable fluid that can be directly extruded into the coagulation bath to form nascent fiber.A water washing step is adopted right after the formation of nascent fiber to eliminate the defects in fiber.Morphology and mechanical properties of the as-prepared ALG/PDDA complex fiber are found to be greatly affected by the water washing,as well as the amount and the type of salt used.As the reported approach is similar to the wet-spinning process which is a commonly used method for industrial production of fibers,it is promising to be applied in larger scale production of PEC fibers.
