Silicon is considered to be one of the most promising anode materials for lithium-ion batteries(LIBs),but its application is limited by the large volume expansion during alloying and dealloying.The constructing of a h...Silicon is considered to be one of the most promising anode materials for lithium-ion batteries(LIBs),but its application is limited by the large volume expansion during alloying and dealloying.The constructing of a high-performance solid electrolyte interface(SEI) film on the surface of the anode material is considered to be one of the effective strategies to mitigate volume expansion of silicon-based anode.In this study,an intermittent discharge strategy which helps to improve the utilization efficiency of electrolyte additive of lithium difluorobisoxalate phosphate(LiDFBOP) is proposed to construct a highly conductive and dense SEI film.The results of electrochemical and physical characterization and theoretical calculations show that the intermittent discharge in the voltage range from open circuit voltage(OCV) to 1.8 V facilitates the diffusion of the soluble products,creates the conditions for the repeated direct contact between Si@C anode and LiDFBOP additive,increases the decomposition of LiDFBOP additive,and thus produces a uniform,dense and inorganics-rich(Li_(2)C_(2)O_(4),LiF and Li_(x)PO_yF_z) SEI film.Subsequently,this SEI film helps to ensure the even intercalation/de-intercalation of Li^(+) in the SEI film and the homogeneous diffusion of Li^(+) inside the Si particles,decreasing the internal stresses and anisotropic phase transitions,maintaining the integrity of Si particles,inhibiting the volume expansion and thu s improving the electrochemical performance of cells.This study not only improves the utilization efficiency of expensive additives through a simply and low-cost method,but also enriches the strategy to improve the electrochemical performance of Si@C anode through interfacial engineering.展开更多
目的建立土壤中吡虫啉、氯虫苯甲酰胺、氟虫腈及其代谢物等6种白蚁防治农药的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。方法样品经乙腈高速匀浆提取,甲醇和0.1%甲酸水为流动相进行梯度洗脱,以CAPCELL PAK C18色谱柱(100 mm×2.1...目的建立土壤中吡虫啉、氯虫苯甲酰胺、氟虫腈及其代谢物等6种白蚁防治农药的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。方法样品经乙腈高速匀浆提取,甲醇和0.1%甲酸水为流动相进行梯度洗脱,以CAPCELL PAK C18色谱柱(100 mm×2.1 mm,2μm)进行HPLC分离,以电喷雾电离串联质谱正、负离子多反应监测(MRM)模式扫描分析,外标法定量。结果 6种白蚁防治剂在1.00～500μg/L的范围内线性关系良好,相关系数R^2大于0.99,方法定量限范围为0.01～0.05 mg/kg,3个添加水平下的平均回收率范围为86.6%～97.4%,相对标准偏差(RSD)范围为3.62%～11.5%,完全满足日常检测的要求。结论该方法前处理简单、快速、灵敏度高、准确,非常适合于土壤中6种白蚁防治农药残留的快速检测及定量分析。展开更多
基金Department of Education of Gansu Province: Industrial Support Plan Project (2022CYZC-23)National Natural Science Foundation of China (22269012)Gansu Key Research and Development Program (23YFGA0053)。
文摘Silicon is considered to be one of the most promising anode materials for lithium-ion batteries(LIBs),but its application is limited by the large volume expansion during alloying and dealloying.The constructing of a high-performance solid electrolyte interface(SEI) film on the surface of the anode material is considered to be one of the effective strategies to mitigate volume expansion of silicon-based anode.In this study,an intermittent discharge strategy which helps to improve the utilization efficiency of electrolyte additive of lithium difluorobisoxalate phosphate(LiDFBOP) is proposed to construct a highly conductive and dense SEI film.The results of electrochemical and physical characterization and theoretical calculations show that the intermittent discharge in the voltage range from open circuit voltage(OCV) to 1.8 V facilitates the diffusion of the soluble products,creates the conditions for the repeated direct contact between Si@C anode and LiDFBOP additive,increases the decomposition of LiDFBOP additive,and thus produces a uniform,dense and inorganics-rich(Li_(2)C_(2)O_(4),LiF and Li_(x)PO_yF_z) SEI film.Subsequently,this SEI film helps to ensure the even intercalation/de-intercalation of Li^(+) in the SEI film and the homogeneous diffusion of Li^(+) inside the Si particles,decreasing the internal stresses and anisotropic phase transitions,maintaining the integrity of Si particles,inhibiting the volume expansion and thu s improving the electrochemical performance of cells.This study not only improves the utilization efficiency of expensive additives through a simply and low-cost method,but also enriches the strategy to improve the electrochemical performance of Si@C anode through interfacial engineering.
