Lithium-ion capacitors(LICs) were fabricated using mesocarbon microbeads(MCMB) as a negative electrode and a mixture of activated carbon(AC) and LiFePO4 as a positive electrode(abbreviated as LAC).The phase structure ...Lithium-ion capacitors(LICs) were fabricated using mesocarbon microbeads(MCMB) as a negative electrode and a mixture of activated carbon(AC) and LiFePO4 as a positive electrode(abbreviated as LAC).The phase structure and morphology of LAC samples were characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM).The electrochemical performance of the LICs was studied using cyclic voltammetry,charge-discharge rate measurements,and cycle performance testing.A LIC with 30 wt% LiFePO4 was found to have the best electrochemical performance with a specific energy density of 69.02 W h kg-1 remaining at 4 C rate after 100 cycles.Compared with an AC-only positive electrode system,the ratio of practical capacity to theoretical calculated capacity of the LICs was enhanced from 42.22% to 56.59%.It was proved that adding LiFePO4 to AC electrodes not only increased the capacity of the positive electrode,but also improved the electrochemical performances of the whole LICs via Li+ pre-doping.展开更多
Tribological properties of Meso-carbon Microbeads (MCMB) powders as a special addi-tive in pentaerythritol were investigated on an Optimal SRV tribotester at 300℃. The coarsely dis-persed lubricant system demonstrate...Tribological properties of Meso-carbon Microbeads (MCMB) powders as a special addi-tive in pentaerythritol were investigated on an Optimal SRV tribotester at 300℃. The coarsely dis-persed lubricant system demonstrates fine lubricious effectiveness at the operation temperature.The friction coefficient dropped from 0.2 to circa 0.12 in the presence of MCMB in pentaerythritolfor the No.45 carbon steel tribomate. Raman spectroscopy analysis indicated the partial transfor-mation of MCMB into increased ordered structures that contributed to the lowering of friction.展开更多
将Li Fe PO4/C锂离子电池分别在25℃（常温）、45℃、55℃下进行0%~100%DOD、1.0 C充/1.0 C放循环测试。结果显示,随温度的升高,电池的循环性能越差。本试验分别比较了电解液、负极材料对不同温度循环性能的影响。电解液中添加高沸点溶...将Li Fe PO4/C锂离子电池分别在25℃（常温）、45℃、55℃下进行0%~100%DOD、1.0 C充/1.0 C放循环测试。结果显示,随温度的升高,电池的循环性能越差。本试验分别比较了电解液、负极材料对不同温度循环性能的影响。电解液中添加高沸点溶剂和抑制Li PF6分解的添加剂、负极使用小粒径中间相碳微球能够提高电池的高温循环性能。展开更多
基金supported by the National Natural Science Foundation of China (51172160,50902102)the National High Technology Research and Development Program of China (2011AA11A232)the National Basic Research Program of China (2012CB720302)
文摘Lithium-ion capacitors(LICs) were fabricated using mesocarbon microbeads(MCMB) as a negative electrode and a mixture of activated carbon(AC) and LiFePO4 as a positive electrode(abbreviated as LAC).The phase structure and morphology of LAC samples were characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM).The electrochemical performance of the LICs was studied using cyclic voltammetry,charge-discharge rate measurements,and cycle performance testing.A LIC with 30 wt% LiFePO4 was found to have the best electrochemical performance with a specific energy density of 69.02 W h kg-1 remaining at 4 C rate after 100 cycles.Compared with an AC-only positive electrode system,the ratio of practical capacity to theoretical calculated capacity of the LICs was enhanced from 42.22% to 56.59%.It was proved that adding LiFePO4 to AC electrodes not only increased the capacity of the positive electrode,but also improved the electrochemical performances of the whole LICs via Li+ pre-doping.
文摘Tribological properties of Meso-carbon Microbeads (MCMB) powders as a special addi-tive in pentaerythritol were investigated on an Optimal SRV tribotester at 300℃. The coarsely dis-persed lubricant system demonstrates fine lubricious effectiveness at the operation temperature.The friction coefficient dropped from 0.2 to circa 0.12 in the presence of MCMB in pentaerythritolfor the No.45 carbon steel tribomate. Raman spectroscopy analysis indicated the partial transfor-mation of MCMB into increased ordered structures that contributed to the lowering of friction.
