The performance of four formulated solvents(labeled as UDS-I, UDS-II, UDS-III, and UDS-IV) for removing methyl mercaptan from liquefied petroleum gas was predicted based on a two-dimensional solubility parameter theor...The performance of four formulated solvents(labeled as UDS-I, UDS-II, UDS-III, and UDS-IV) for removing methyl mercaptan from liquefied petroleum gas was predicted based on a two-dimensional solubility parameter theory. The calculation results show that UDS-IV has the closest solubility parameter to that of methyl mercaptan as compared with other tested solvents, indicating the strongest affinity and the highest solubility for methyl mercaptan. The industrial tests at a plant for desulfurization of LPG produced from the delayed coker have shown that the UDS solvents have the excellent performance for removal of organosulfur compounds(mainly methyl mercaptan). Although the sulfur loading dramatically increases, the total sulfur content of LPG treated with UDS-IV can be reduced by about 50% in comparison with N-methyl diethanolamine. In addition, UDS-IV has superior regeneration performance and selectivity for sulfur compounds over hydrocarbons. The industrial test and the solubility parameter calculation results are in good agreement with each other.展开更多
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
Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)deli...Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^(-1),stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^(-2) for electrode with up to 10.3 mg cm^(-2) loading.New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li_(2)S)or lithium disulfide(Li_(2)S_(2))was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)calculations.Therefore,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur batteries.This study sets new trends for avenues of further research to advance Li-S battery technologies.展开更多
The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables al...The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.展开更多
基金the financial support from the National Key Science and Technology Project of China (2011ZX05017-005)
文摘The performance of four formulated solvents(labeled as UDS-I, UDS-II, UDS-III, and UDS-IV) for removing methyl mercaptan from liquefied petroleum gas was predicted based on a two-dimensional solubility parameter theory. The calculation results show that UDS-IV has the closest solubility parameter to that of methyl mercaptan as compared with other tested solvents, indicating the strongest affinity and the highest solubility for methyl mercaptan. The industrial tests at a plant for desulfurization of LPG produced from the delayed coker have shown that the UDS solvents have the excellent performance for removal of organosulfur compounds(mainly methyl mercaptan). Although the sulfur loading dramatically increases, the total sulfur content of LPG treated with UDS-IV can be reduced by about 50% in comparison with N-methyl diethanolamine. In addition, UDS-IV has superior regeneration performance and selectivity for sulfur compounds over hydrocarbons. The industrial test and the solubility parameter calculation results are in good agreement with each other.
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support from the National Natural Science Foundations of China(grants 51622208,21703149,and 51872193)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^(-1),stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^(-2) for electrode with up to 10.3 mg cm^(-2) loading.New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li_(2)S)or lithium disulfide(Li_(2)S_(2))was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)calculations.Therefore,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur batteries.This study sets new trends for avenues of further research to advance Li-S battery technologies.
基金support from the National Natural Science Foundations of China (grants 52071226 and 51872193)the Natural Science Foundations of Jiangsu Province (BE2020003-3 and BK20201171)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.
