There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of st...There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of stable depression-compression-extension.The first three types of basins had been intensely influenced by Hercynian and Alpine tectonic movement,while the later two types of basins always exist in a stable extension environment.Different basin evolution caused the obviously hydrocarbon distribution difference.In North Africa,marginal craton sag and rift basins show great expedition potential of hydrocarbon,marginal craton sag basins had good formation and preservation of Lower Silurian hot shale,tectonic-strata traps and migration pathway formed by Hercynian unconformity,and rift basins had excellent Upper Cretaceous marine source rocks and good hydrocarbon preservation with little tectonic activity.Meanwhile,in the salt-containing passive margin basins and delta basins of West Africa,thick strata containing high quality source rocks and plastic strata were well developed.Source rocks of high maturity,good hydrocarbon preservation,growth faults and deformational structure traps were formed by abundant overlying sediments and sources supplied from Tertiary large water system.展开更多
The excellent energy storage performance of covalent sulfur-carbon material has gradually attracted great interest. However, in the electrochemical sodium storage process, the bond evolution mechanism remains an elusi...The excellent energy storage performance of covalent sulfur-carbon material has gradually attracted great interest. However, in the electrochemical sodium storage process, the bond evolution mechanism remains an elusive topic. Herein, we develop a one-step annealing strategy to achieve a high covalent sulfur-carbon bridged hybrid(HCSC)utilizing phenylphosphinic acid as the carbon-source/catalyst and sodium sulfate as the sulfur-precursor/salt template, in which the sulfur mainly exists in the forms of C–S–C and C–S–S–C. Notably, most of the bridge bonds are electrochemically cleaved when the cycling voltage is lower than0.6 V versus Na/Na+, leading to the appearance of two visible redox peaks in the following cyclic voltammogram(CV) tests.The in-situ and ex-situ characterizations demonstrate that S^2- is formed in the reduction process and the carbon skeleton is concomitantly and irreversibly isomerized. Thus, the cleaved sulfur and isomerized carbon could jointly contribute to the sodium storage in 0.01–3.0 V. In a Na-S battery system, the activated HCSC in cut off voltage window of 0.6–2.8 V achieves a high reversible capacity(770 mA h g^-1 at 300 mA g^-1). This insight reveals the charge storage mechanism of sulfur-carbon bridged hybrid and provides an improved enlightenment on the interfacial chemistry of electrode materials.展开更多
文摘There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of stable depression-compression-extension.The first three types of basins had been intensely influenced by Hercynian and Alpine tectonic movement,while the later two types of basins always exist in a stable extension environment.Different basin evolution caused the obviously hydrocarbon distribution difference.In North Africa,marginal craton sag and rift basins show great expedition potential of hydrocarbon,marginal craton sag basins had good formation and preservation of Lower Silurian hot shale,tectonic-strata traps and migration pathway formed by Hercynian unconformity,and rift basins had excellent Upper Cretaceous marine source rocks and good hydrocarbon preservation with little tectonic activity.Meanwhile,in the salt-containing passive margin basins and delta basins of West Africa,thick strata containing high quality source rocks and plastic strata were well developed.Source rocks of high maturity,good hydrocarbon preservation,growth faults and deformational structure traps were formed by abundant overlying sediments and sources supplied from Tertiary large water system.
基金supported by the National Key Research and Development Program of China(2017YFB0102003 and2018YFB0104204)the National Natural Science Foundation of China(51622406,21673298 and 21473258)+2 种基金Young Elite Scientists Sponsorship Program By CAST(2017QNRC001)the Project of Innovation Driven Plan in Central South University(2017CX004 and 2018CX005)the Program for Innovative Team(in Science and Technology)in the University of Henan Province of China(17IRTSTHN003)
文摘The excellent energy storage performance of covalent sulfur-carbon material has gradually attracted great interest. However, in the electrochemical sodium storage process, the bond evolution mechanism remains an elusive topic. Herein, we develop a one-step annealing strategy to achieve a high covalent sulfur-carbon bridged hybrid(HCSC)utilizing phenylphosphinic acid as the carbon-source/catalyst and sodium sulfate as the sulfur-precursor/salt template, in which the sulfur mainly exists in the forms of C–S–C and C–S–S–C. Notably, most of the bridge bonds are electrochemically cleaved when the cycling voltage is lower than0.6 V versus Na/Na+, leading to the appearance of two visible redox peaks in the following cyclic voltammogram(CV) tests.The in-situ and ex-situ characterizations demonstrate that S^2- is formed in the reduction process and the carbon skeleton is concomitantly and irreversibly isomerized. Thus, the cleaved sulfur and isomerized carbon could jointly contribute to the sodium storage in 0.01–3.0 V. In a Na-S battery system, the activated HCSC in cut off voltage window of 0.6–2.8 V achieves a high reversible capacity(770 mA h g^-1 at 300 mA g^-1). This insight reveals the charge storage mechanism of sulfur-carbon bridged hybrid and provides an improved enlightenment on the interfacial chemistry of electrode materials.
