To address the issues in aqueous zinc-ion batteries(ZIBs),including the formation of zinc dendrites and the occurrence of harmful side reactions(e.g.,the hydrogen evolution reaction),which seriously affect the perform...To address the issues in aqueous zinc-ion batteries(ZIBs),including the formation of zinc dendrites and the occurrence of harmful side reactions(e.g.,the hydrogen evolution reaction),which seriously affect the performance of the battery,a sulfonated covalent organic framework(SCOF),TpPa-SO3H,was synthesized and the quasi-solid polymer electrolyte SCOF-PVDF/Zn(CF3SO3)2 was successfully prepared with a polymer matrix of PVDF and an ion-transporting backbone of SCOF.Both of Zn//Zn symmetric batteries and Zn//NH4V4O10 full batteries assembled using SCOF-PVDF/Zn(CF3SO3)2 electrolyte exhibited excellent battery cycling stability.The high ionic conductivity of 3×10^(-4)S·cm^(-1)could be achieved.The assembled symmetric batteries demonstrated a cycle life of 980 h at a current density of 2 mA·cm^(-2).The Zn//NH4V4O10 full battery can provide a specific capacity of 196 mAh·g^(-1)at a high current density of 10 A·g^(-1).展开更多
Forest management practices such as prescribed burning and thinning in forest ecosystems may alter the properties of soil organic matter （SOM）. In this study, surface softs from field plots in the Bankhead National ...Forest management practices such as prescribed burning and thinning in forest ecosystems may alter the properties of soil organic matter （SOM）. In this study, surface softs from field plots in the Bankhead National Forest, Alabama, USA, were used to investigate possible SOM transformations induced by thinning and burning. Elemental analysis and solid-state 13C cross polarization magic angle spinning nuclear magnetic resonance （13C CPMAS NMR） spectroscopy were used to characterize SOM fractions in whole soils, humic substances, and density fractions. Our data revealed that the changes in SOM fractions due to the repeated burning carried out in the forest ecosystem studied were involved mainly with alkyl C, O-alkyl C, and carbohydrate functional groups, implying that most prominent reactions that occurred involved dehydrogenation, de-oxygenation, and decarboxylation. In addition, burning and thinning might have also affected the distribution and composition of free and occluded particulate SOM fractions. The limited structural changes in SOM fractions suggested that low-intensity prescribed fire in the forest ecosystem studied will not create major structural changes in SOM fractions.展开更多
基金supported by the National Natural Science Foundation of China(22071021).
文摘To address the issues in aqueous zinc-ion batteries(ZIBs),including the formation of zinc dendrites and the occurrence of harmful side reactions(e.g.,the hydrogen evolution reaction),which seriously affect the performance of the battery,a sulfonated covalent organic framework(SCOF),TpPa-SO3H,was synthesized and the quasi-solid polymer electrolyte SCOF-PVDF/Zn(CF3SO3)2 was successfully prepared with a polymer matrix of PVDF and an ion-transporting backbone of SCOF.Both of Zn//Zn symmetric batteries and Zn//NH4V4O10 full batteries assembled using SCOF-PVDF/Zn(CF3SO3)2 electrolyte exhibited excellent battery cycling stability.The high ionic conductivity of 3×10^(-4)S·cm^(-1)could be achieved.The assembled symmetric batteries demonstrated a cycle life of 980 h at a current density of 2 mA·cm^(-2).The Zn//NH4V4O10 full battery can provide a specific capacity of 196 mAh·g^(-1)at a high current density of 10 A·g^(-1).
基金supported by the USDA National Institute of Food and Agriculture(NIFA),Evans Allen Grant,USA(No.224120)the National Science Foundation(NSF-CREST-CFEA),USA(No.1036600)the Agricultural Experimental Station,Alabama A&M University,Alabama,USA(Journal#:660)
文摘Forest management practices such as prescribed burning and thinning in forest ecosystems may alter the properties of soil organic matter （SOM）. In this study, surface softs from field plots in the Bankhead National Forest, Alabama, USA, were used to investigate possible SOM transformations induced by thinning and burning. Elemental analysis and solid-state 13C cross polarization magic angle spinning nuclear magnetic resonance （13C CPMAS NMR） spectroscopy were used to characterize SOM fractions in whole soils, humic substances, and density fractions. Our data revealed that the changes in SOM fractions due to the repeated burning carried out in the forest ecosystem studied were involved mainly with alkyl C, O-alkyl C, and carbohydrate functional groups, implying that most prominent reactions that occurred involved dehydrogenation, de-oxygenation, and decarboxylation. In addition, burning and thinning might have also affected the distribution and composition of free and occluded particulate SOM fractions. The limited structural changes in SOM fractions suggested that low-intensity prescribed fire in the forest ecosystem studied will not create major structural changes in SOM fractions.
