Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) for large-scale energy storage considering the abundance and low cost of Na-containing resources. However, the energy density of S...Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) for large-scale energy storage considering the abundance and low cost of Na-containing resources. However, the energy density of SIBs has been limited by the typically low specific capacities of traditional intercalation-based cathodes. Metal fluorides, in contrast, can deliver much higher capacities based on multi-electron conversion reactions. Among metal fluorides, CuF_(2) presents a theoretical specific capacity as high as 528 mAh/g while its Na-ion storage mechanism has been rarely reported. Here, we report CuF_(2) as a SIB cathode, which delivers a high capacity of 502 mAh/g but suffers from poor electrochemical reversibility. As a solution, we adjust the cell configuration by inserting a carbon-coated separator, which hinders the transportation of dissolved Cu ions and improves the reversibility of the CuF_(2) cathode. By using in-situ XRD measurements and theoretical calculation, we propose that a one-step conversion reaction occurs during the discharge process, and a reconversion reaction competes with the oxidization of Cu to dissolved Cu ion during the charge process.展开更多
Hydrofluorosis is a major public health problem in India, which is aggravated by presence or absence of some minerals in water or food. Fluoride by itself or in combination with other elements like molybdenum （Mo） i...Hydrofluorosis is a major public health problem in India, which is aggravated by presence or absence of some minerals in water or food. Fluoride by itself or in combination with other elements like molybdenum （Mo） in diet or water changes excretion/retention of bone minerals. Sorghum and pearl millet grown and consumed in fluorosis endemic areas contained significantly higher amounts of Mo than that grown in non-fluorotic areas in India.展开更多
基金financial support by the National Natural Science Foundation of China (No. 21975186)“Shanghai Rising-Star Program”(No. 19QA1409300)。
文摘Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) for large-scale energy storage considering the abundance and low cost of Na-containing resources. However, the energy density of SIBs has been limited by the typically low specific capacities of traditional intercalation-based cathodes. Metal fluorides, in contrast, can deliver much higher capacities based on multi-electron conversion reactions. Among metal fluorides, CuF_(2) presents a theoretical specific capacity as high as 528 mAh/g while its Na-ion storage mechanism has been rarely reported. Here, we report CuF_(2) as a SIB cathode, which delivers a high capacity of 502 mAh/g but suffers from poor electrochemical reversibility. As a solution, we adjust the cell configuration by inserting a carbon-coated separator, which hinders the transportation of dissolved Cu ions and improves the reversibility of the CuF_(2) cathode. By using in-situ XRD measurements and theoretical calculation, we propose that a one-step conversion reaction occurs during the discharge process, and a reconversion reaction competes with the oxidization of Cu to dissolved Cu ion during the charge process.
文摘Hydrofluorosis is a major public health problem in India, which is aggravated by presence or absence of some minerals in water or food. Fluoride by itself or in combination with other elements like molybdenum （Mo） in diet or water changes excretion/retention of bone minerals. Sorghum and pearl millet grown and consumed in fluorosis endemic areas contained significantly higher amounts of Mo than that grown in non-fluorotic areas in India.
