A prismatic 204056-type high power lithium-ion battery was developed.Modified LiMn2O4 and carbonaceous mesophase sphere(CMS)were adopted as the cathode and anode,respectively.The effects of proportion of conductive ca...A prismatic 204056-type high power lithium-ion battery was developed.Modified LiMn2O4 and carbonaceous mesophase sphere(CMS)were adopted as the cathode and anode,respectively.The effects of proportion of conductive carbon black in cathode and the rest time after discharge on the electrochemical properties of batteries were investigated.The electrochemical tests show that the proportion of conductive carbon black in cathodes affects the high rate capability and discharge voltage plateau distinctly.The battery with 3.0%of conductive carbon black in cathode shows excellent electrochemical performances when being charged/discharged within 2.5-4.2 V at room temperature.The discharge capacity at 20C rate is 94.4%of that at 1C rate,and the capacity retention ratio charged at 1C and discharged at 5C is 86.6%after 390 cycles at room temperature.The test result of impulse discharge at 50C for 5 s shows that the battery has outstanding high rate discharge performance when the battery is in the depth of charge of 90%,75%,60%,45%,30%and 15%.The battery also shows good charge performance.When the battery is charged at 0.5C,1C,2C and 4C,the ratios of capacity for constant current charge are 98.4%,96.4%,91.0%and 72.9%of the whole charge capacity,respectively.In addition,the rest time after discharge affects the cycle performance distinctly when the battery is discharged at high rate.展开更多
Modulating the atomic structure and surface property represents a pivotal and intriguing approach to tai-loring the energy storage performance of battery materials,but their simultaneous modulation via simple processe...Modulating the atomic structure and surface property represents a pivotal and intriguing approach to tai-loring the energy storage performance of battery materials,but their simultaneous modulation via simple processes remains a grand challenge.Taking TiO_(2)as an example,here we report the structure and sur-face modulation through a simple two-step operation,hydrogenation and fluorination,which impart high electrical conductivity and robust surface activity to the material.Hydrogenation introduces Ti^(3+)species in the TiO_(2)bulk to accelerate electron transport,while surface fluorination speeds up sodium-ion reaction dynamics.This modulated TiO_(2)exhibits robust Na+storage,affording 181 mAh g^(−1)over 2500 cycles at a high rate of 20 C.In addition,when paring with a commercial Na_(3)V_(2)(PO_(4))2 O_(2)F cathode,the designated TiO_(2)allows the full cell to deliver a remarkable power of 3700 W kg^(−1),outperforming most sodium-ion batteries.The correlation between the robust performance and the material property is understood through energy band analysis and density functional theory calculations.展开更多
通过机械球磨制备不同质量比的LCO/NCA混合正极材料,采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征其相结构和微观形貌,研究了这种材料的电化学性能。结果表明,两种正极材料球磨混合后其晶体结构均未改变,但是初始的NCA球形二次颗粒...通过机械球磨制备不同质量比的LCO/NCA混合正极材料,采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征其相结构和微观形貌,研究了这种材料的电化学性能。结果表明,两种正极材料球磨混合后其晶体结构均未改变,但是初始的NCA球形二次颗粒被打散,形成的纳米粒子弥散填充在LCO微米颗粒的孔隙之间,提高了正极材料的涂膜密度和二者之间的接触紧密性。当LCO:NCA=6:4时混合正极材料具有最佳的颗粒级配效果,其首次充放电效率最高,为92.4%;在10 C (1 C=140 m A·g-1)倍率下的比容量(136 mA·h·g-1)是0.2 C时的78.0%,出现了明显的协同增强效果;在1 C倍率下循环100次其容量保持率为89.8%,表现出优异的电化学性能。展开更多
基金Project(2007CB613607)supported by the National Basic Research Program of China
文摘A prismatic 204056-type high power lithium-ion battery was developed.Modified LiMn2O4 and carbonaceous mesophase sphere(CMS)were adopted as the cathode and anode,respectively.The effects of proportion of conductive carbon black in cathode and the rest time after discharge on the electrochemical properties of batteries were investigated.The electrochemical tests show that the proportion of conductive carbon black in cathodes affects the high rate capability and discharge voltage plateau distinctly.The battery with 3.0%of conductive carbon black in cathode shows excellent electrochemical performances when being charged/discharged within 2.5-4.2 V at room temperature.The discharge capacity at 20C rate is 94.4%of that at 1C rate,and the capacity retention ratio charged at 1C and discharged at 5C is 86.6%after 390 cycles at room temperature.The test result of impulse discharge at 50C for 5 s shows that the battery has outstanding high rate discharge performance when the battery is in the depth of charge of 90%,75%,60%,45%,30%and 15%.The battery also shows good charge performance.When the battery is charged at 0.5C,1C,2C and 4C,the ratios of capacity for constant current charge are 98.4%,96.4%,91.0%and 72.9%of the whole charge capacity,respectively.In addition,the rest time after discharge affects the cycle performance distinctly when the battery is discharged at high rate.
基金The authors are grateful to the financial support of the National Natural Science Foundation of China(Nos.52172219,51872192,52025028,and 51772197)the Thousand Young Talents Plan,the Jiangsu Natural Science Foundation(No.BK20180002)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJA170001)of the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Modulating the atomic structure and surface property represents a pivotal and intriguing approach to tai-loring the energy storage performance of battery materials,but their simultaneous modulation via simple processes remains a grand challenge.Taking TiO_(2)as an example,here we report the structure and sur-face modulation through a simple two-step operation,hydrogenation and fluorination,which impart high electrical conductivity and robust surface activity to the material.Hydrogenation introduces Ti^(3+)species in the TiO_(2)bulk to accelerate electron transport,while surface fluorination speeds up sodium-ion reaction dynamics.This modulated TiO_(2)exhibits robust Na+storage,affording 181 mAh g^(−1)over 2500 cycles at a high rate of 20 C.In addition,when paring with a commercial Na_(3)V_(2)(PO_(4))2 O_(2)F cathode,the designated TiO_(2)allows the full cell to deliver a remarkable power of 3700 W kg^(−1),outperforming most sodium-ion batteries.The correlation between the robust performance and the material property is understood through energy band analysis and density functional theory calculations.
文摘通过机械球磨制备不同质量比的LCO/NCA混合正极材料,采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征其相结构和微观形貌,研究了这种材料的电化学性能。结果表明,两种正极材料球磨混合后其晶体结构均未改变,但是初始的NCA球形二次颗粒被打散,形成的纳米粒子弥散填充在LCO微米颗粒的孔隙之间,提高了正极材料的涂膜密度和二者之间的接触紧密性。当LCO:NCA=6:4时混合正极材料具有最佳的颗粒级配效果,其首次充放电效率最高,为92.4%;在10 C (1 C=140 m A·g-1)倍率下的比容量(136 mA·h·g-1)是0.2 C时的78.0%,出现了明显的协同增强效果;在1 C倍率下循环100次其容量保持率为89.8%,表现出优异的电化学性能。
