Hard carbon is regarded as a promising anode material for sodium-ion batteries,while it remains a huge challenge to initial coulombic efficiency and rate performance.Numerous studies show that critical structural feat...Hard carbon is regarded as a promising anode material for sodium-ion batteries,while it remains a huge challenge to initial coulombic efficiency and rate performance.Numerous studies show that critical structural features in hard carbon,namely defects,crystallites,and close pores,are directly responsible for the electrochemical performance in sodium-ion batteries.Here,we employ bamboo-derived hard carbon to systematically regulate the defects and crystallites in hard carbon by introducing mechanical activation.Benefiting from ball milling,the intermediate product with a high specific area more easily transforms into hard carbon,which possesses abundant closed pores,effective interlayer spacing,and suitable sodium storage defects,helping to improve the sodium ion storage performance.As a result,the hard carbon ball milled for 20 min presents a high reversible capacity of 315.2 mA·h/g at 17.5 mA/g with an initial coulombic efficiency up to 79.3%,as well as good rate and cycling performances.展开更多
A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the a...A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.展开更多
基金Project(2022RC3048)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject support by the Guangdong Greenway Technology Co.Ltd.,China。
文摘Hard carbon is regarded as a promising anode material for sodium-ion batteries,while it remains a huge challenge to initial coulombic efficiency and rate performance.Numerous studies show that critical structural features in hard carbon,namely defects,crystallites,and close pores,are directly responsible for the electrochemical performance in sodium-ion batteries.Here,we employ bamboo-derived hard carbon to systematically regulate the defects and crystallites in hard carbon by introducing mechanical activation.Benefiting from ball milling,the intermediate product with a high specific area more easily transforms into hard carbon,which possesses abundant closed pores,effective interlayer spacing,and suitable sodium storage defects,helping to improve the sodium ion storage performance.As a result,the hard carbon ball milled for 20 min presents a high reversible capacity of 315.2 mA·h/g at 17.5 mA/g with an initial coulombic efficiency up to 79.3%,as well as good rate and cycling performances.
基金Project(2007BAE12B00) supported by the National Key Technology R&D Program of ChinaProject(50974136) supported by the National Natural Science Foundation of China
文摘A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.
