通过冻干-煅烧合成了一氧化锰/石墨烯(MnO/rGO)复合材料,并将其用作锂离子电池负极材料.在500 m A·g^(-1)的电流密度下,MnO/rGO复合材料表现出高达830 m Ah·g^(-1)的可逆容量,且在充放电循环160圈后,其可逆容量依然高达805m A...通过冻干-煅烧合成了一氧化锰/石墨烯(MnO/rGO)复合材料,并将其用作锂离子电池负极材料.在500 m A·g^(-1)的电流密度下,MnO/rGO复合材料表现出高达830 m Ah·g^(-1)的可逆容量,且在充放电循环160圈后,其可逆容量依然高达805m Ah·g^(-1).倍率测试结果显示,循环225圈后,在2.0 A·g^(-1)的电流密度下,其可逆容量高达412 m Ah·g^(-1).复合材料中的石墨烯在提高材料导电性的同时有效地缓解了一氧化锰充放电过程中的体积膨胀.通过对比容量-电压的微分分析,发现复合材料超出一氧化锰理论容量的部分是由形成了更高价态的锰引起的.MnO/rGO复合材料比纯一氧化锰(p-MnO)更容易出现高价态的锰,可能是因为rGO上残留的氧为电极反应提供了额外所需的氧源.该一氧化锰/石墨烯复合材料因其简单绿色的合成过程及优异的电化学性质,有望在未来的锂电负极中得到广泛的实际应用.展开更多
Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2(NCM811)was synthe-sized via a spray drying method.The effect of different spray drying flow-rates(200,250,300,and 400 mL·min^-1)on the structural and elect...Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2(NCM811)was synthe-sized via a spray drying method.The effect of different spray drying flow-rates(200,250,300,and 400 mL·min^-1)on the structural and electrochemical properties of NCM811 are investigated.We find that the contents of Ni,Co,and Mn in the NCM811 cathode materials do not change significantly with the changing flow-rate,but the lattice parameter and morphology of the materials are significantly affected.Under the optimal spray drying flow-rate(250 mL·min^-1),the obtained NCM811 cathode(250NCM811)exhibits the best crystallinity,with the highest ratio of I(003)/I(104)in the XRD pattern.SEM images reveal the spherical morphology of 250NCM811 and the average diameter of about 5 mm.The results of electrochemical test show that the reversible capacity of 250NCM811 reaches 210 mA·g^-1 at 0.2 C(1 C=280 mA·g^-1).After 100 charge-discharge cycles at 1 C,the battery retains more than 94%of its initial capacity.Overall,spray drying flow-rate demonstrates great effect on the electrochemical properties of NCM811.展开更多
文摘通过冻干-煅烧合成了一氧化锰/石墨烯(MnO/rGO)复合材料,并将其用作锂离子电池负极材料.在500 m A·g^(-1)的电流密度下,MnO/rGO复合材料表现出高达830 m Ah·g^(-1)的可逆容量,且在充放电循环160圈后,其可逆容量依然高达805m Ah·g^(-1).倍率测试结果显示,循环225圈后,在2.0 A·g^(-1)的电流密度下,其可逆容量高达412 m Ah·g^(-1).复合材料中的石墨烯在提高材料导电性的同时有效地缓解了一氧化锰充放电过程中的体积膨胀.通过对比容量-电压的微分分析,发现复合材料超出一氧化锰理论容量的部分是由形成了更高价态的锰引起的.MnO/rGO复合材料比纯一氧化锰(p-MnO)更容易出现高价态的锰,可能是因为rGO上残留的氧为电极反应提供了额外所需的氧源.该一氧化锰/石墨烯复合材料因其简单绿色的合成过程及优异的电化学性质,有望在未来的锂电负极中得到广泛的实际应用.
基金Supported by the National Natural Science Foundation of China(No.51602310)Fujian Provincial Department of Science and Technology(2019T3017)the DNL Cooperation Fund,CAS(DNL180308)。
文摘Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2(NCM811)was synthe-sized via a spray drying method.The effect of different spray drying flow-rates(200,250,300,and 400 mL·min^-1)on the structural and electrochemical properties of NCM811 are investigated.We find that the contents of Ni,Co,and Mn in the NCM811 cathode materials do not change significantly with the changing flow-rate,but the lattice parameter and morphology of the materials are significantly affected.Under the optimal spray drying flow-rate(250 mL·min^-1),the obtained NCM811 cathode(250NCM811)exhibits the best crystallinity,with the highest ratio of I(003)/I(104)in the XRD pattern.SEM images reveal the spherical morphology of 250NCM811 and the average diameter of about 5 mm.The results of electrochemical test show that the reversible capacity of 250NCM811 reaches 210 mA·g^-1 at 0.2 C(1 C=280 mA·g^-1).After 100 charge-discharge cycles at 1 C,the battery retains more than 94%of its initial capacity.Overall,spray drying flow-rate demonstrates great effect on the electrochemical properties of NCM811.
