Potassium-ions batteries(PIBs)are attracting increasing attention as up-and-coming youngster in largescale grid-level energy storage benefiting from its low-cost and high energy density.Nevertheless,enough researches ...Potassium-ions batteries(PIBs)are attracting increasing attention as up-and-coming youngster in largescale grid-level energy storage benefiting from its low-cost and high energy density.Nevertheless,enough researches regarding indispensable cathode materials for PIBs are badly absent.Herein,we synthesize K-deficient layered manganese-based oxides(P2-K_(0.21)MnO_(2) and P3-K_(0.23)MnO_(2))and investigate them as cathode of PIBs for the first time.As the newcomer of potassium-containing layered manganese-based oxides(K_(x)MnO_(2))group,P2-K_(0.21)MnO_(2) delivers high discharge capacity of 99.3 mAh g^(-1) and P3-K_(0.23)MnO_(2) exhibits remarkable capacity retention rate of 75.5%.Besides,in-situ XRD and ex-situ XRD measurements reveal the reversible phase transition of P2-K_(0.21)MnO_(2) and P3-K_(0.23)MnO_(2) with the potassium-ions extraction and reinsertion,respectively.This work contributes to a better understanding for the potassium storage in K-deficient layered K_(x)MnO_(2)(x≤0.23),possessing an important basic scientific significance for the exploitation and application of layered K_(x)MnO_(2) in PIBs.展开更多
通过对平湖糟蛋样品前处理方式以及乙醇测定反应体系的优化,建立了重铬酸钾分光光度法测定平湖糟蛋中乙醇含量的方法。平湖糟蛋样品中的乙醇经蒸馏法充分提取,提取液在5.0mL重铬酸钾溶液(50g/L)和2.5mL硫酸溶液(50∶50,v/v)介质中于100...通过对平湖糟蛋样品前处理方式以及乙醇测定反应体系的优化,建立了重铬酸钾分光光度法测定平湖糟蛋中乙醇含量的方法。平湖糟蛋样品中的乙醇经蒸馏法充分提取,提取液在5.0mL重铬酸钾溶液(50g/L)和2.5mL硫酸溶液(50∶50,v/v)介质中于100℃水浴反应15min,恢复室温后采用分光光度法在585nm处测定吸光度值。该方法能较好排除基质效应影响,测定结果准确度高,乙醇含量在0.00~250.00g/kg范围内线性关系良好,相关系数大于0.999,加标回收率为96.2%~99.5%,精密度(relative standard deviation,RSD)为0.69%~2.28%。该方法操作简单、准确度高、回收率好,能准确地对糟蛋样品中乙醇进行定量检测。展开更多
基金support from the Key Project of Guangdong Province Nature Science Foundation (No. 2017B030311013)the Scientific and Technological Plan of Guangdong Province, Guangzhou and Qingyuan City, China (Nos. 2019B090905005, 2019B090911004, 2017B020227009, 2019DZX008, 2019A004)+2 种基金the financial support from the National Key R&D Program of China (2018YFB1502600)the National Natural Science Foundation of China (No. 51922042 and 51872098)the Sino-Singapore International Joint Research Institute (SSIJRI), Guangzhou 510700, China.
文摘Potassium-ions batteries(PIBs)are attracting increasing attention as up-and-coming youngster in largescale grid-level energy storage benefiting from its low-cost and high energy density.Nevertheless,enough researches regarding indispensable cathode materials for PIBs are badly absent.Herein,we synthesize K-deficient layered manganese-based oxides(P2-K_(0.21)MnO_(2) and P3-K_(0.23)MnO_(2))and investigate them as cathode of PIBs for the first time.As the newcomer of potassium-containing layered manganese-based oxides(K_(x)MnO_(2))group,P2-K_(0.21)MnO_(2) delivers high discharge capacity of 99.3 mAh g^(-1) and P3-K_(0.23)MnO_(2) exhibits remarkable capacity retention rate of 75.5%.Besides,in-situ XRD and ex-situ XRD measurements reveal the reversible phase transition of P2-K_(0.21)MnO_(2) and P3-K_(0.23)MnO_(2) with the potassium-ions extraction and reinsertion,respectively.This work contributes to a better understanding for the potassium storage in K-deficient layered K_(x)MnO_(2)(x≤0.23),possessing an important basic scientific significance for the exploitation and application of layered K_(x)MnO_(2) in PIBs.
文摘通过对平湖糟蛋样品前处理方式以及乙醇测定反应体系的优化,建立了重铬酸钾分光光度法测定平湖糟蛋中乙醇含量的方法。平湖糟蛋样品中的乙醇经蒸馏法充分提取,提取液在5.0mL重铬酸钾溶液(50g/L)和2.5mL硫酸溶液(50∶50,v/v)介质中于100℃水浴反应15min,恢复室温后采用分光光度法在585nm处测定吸光度值。该方法能较好排除基质效应影响,测定结果准确度高,乙醇含量在0.00~250.00g/kg范围内线性关系良好,相关系数大于0.999,加标回收率为96.2%~99.5%,精密度(relative standard deviation,RSD)为0.69%~2.28%。该方法操作简单、准确度高、回收率好,能准确地对糟蛋样品中乙醇进行定量检测。
