In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typ...In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typical layered structure with R3m and C2/m space group observed from X-ray powder diffraction(XRD).Electron microscopy micrograph(SEM)reveals that the particle sizes in the range of0.4-1.1μm increase with an increase of x value.Li1.2(Mn0.6Ni0.2Co0.2)0.8O2sample delivers a larger initial discharge capacity of275.7mA·h/g at the current density of20mA/g in the potential range of2.0-4.8V,while Li1.1(Mn0.6Ni0.2Co0.2)0.9O2shows a better cycle performance with a capacity retention of93.8%at0.2C after50cycles,showing better reaction kinetics of lithium ion insertion and extraction.展开更多
Due to the high theoretical capacity and energy density,conversion-type metal fluorides have captured plenty of attentions but still suffer from the inferior kinetic behaviors and serious capacity fading.For addressin...Due to the high theoretical capacity and energy density,conversion-type metal fluorides have captured plenty of attentions but still suffer from the inferior kinetic behaviors and serious capacity fading.For addressing the issues above,the strategies of surface/interface engineering are utilized for the preparation of sphere-like porous FeF3@C materials,where the as-resulted sample displays the uniform particle size(~150 nm in radii)and the ultrathin carbon layers(thickness of~10 nm).Significantly,benefitting from the rich oxygen of precursor,the interfacial chemical bonds Fe-O-C are successfully constructed between carbon matrix and FeF3 materials,accompanying by the enhancements of ions/electrons(e-)conductivity and stability.When used as Li-storage cathodes,the initial lithium-ions storage capacity could reach up to~400mAh·g^(-1) at 0.1 A·g^(-1).Even at 1.0 A·g^(-1),the capacity could be still remained at about 210 mAh·g^(-1),with the retention of 85%after 400 cycles.Assisted by the detailed kinetic behaviors,the considerable electrochemical properties come from the enhanced diffusion-controlled contributions,whilst the segregation of Fe with LiF is effectively alleviated by unique architecture.Moreover,during cycling,solid electrolyte interface film is reversibly formed/decomposed.Thus,this work is expected to offer rational exterior/interfacial designing strategies for metalbased samples.展开更多
基金Project(21473258) supported by the National Natural Science Foundation of ChinaProject(13JJ1004) supported by Distinguished Young Scientists of Hunan Province,ChinaProject(NCET-11-0513) supported by Program for the New Century Excellent Talents in University,China
文摘In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typical layered structure with R3m and C2/m space group observed from X-ray powder diffraction(XRD).Electron microscopy micrograph(SEM)reveals that the particle sizes in the range of0.4-1.1μm increase with an increase of x value.Li1.2(Mn0.6Ni0.2Co0.2)0.8O2sample delivers a larger initial discharge capacity of275.7mA·h/g at the current density of20mA/g in the potential range of2.0-4.8V,while Li1.1(Mn0.6Ni0.2Co0.2)0.9O2shows a better cycle performance with a capacity retention of93.8%at0.2C after50cycles,showing better reaction kinetics of lithium ion insertion and extraction.
基金financially supported by the National Natural Science Foundation of China(Nos.52004334,52003230,91962223 and 21473258)the Science and TechnologyInnovation Program of Hunan Province(No.2021RC2091)+3 种基金the China Postdoctoral Science Foundation(No.2021M692703)Natural Science Foundation of Hunan Province(No.2021JJ20073)National Key Research and Development Program of China(Nos.2018YFC1901601 and 2019YFC1907801)Collaborative Innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources,Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2017-13)。
文摘Due to the high theoretical capacity and energy density,conversion-type metal fluorides have captured plenty of attentions but still suffer from the inferior kinetic behaviors and serious capacity fading.For addressing the issues above,the strategies of surface/interface engineering are utilized for the preparation of sphere-like porous FeF3@C materials,where the as-resulted sample displays the uniform particle size(~150 nm in radii)and the ultrathin carbon layers(thickness of~10 nm).Significantly,benefitting from the rich oxygen of precursor,the interfacial chemical bonds Fe-O-C are successfully constructed between carbon matrix and FeF3 materials,accompanying by the enhancements of ions/electrons(e-)conductivity and stability.When used as Li-storage cathodes,the initial lithium-ions storage capacity could reach up to~400mAh·g^(-1) at 0.1 A·g^(-1).Even at 1.0 A·g^(-1),the capacity could be still remained at about 210 mAh·g^(-1),with the retention of 85%after 400 cycles.Assisted by the detailed kinetic behaviors,the considerable electrochemical properties come from the enhanced diffusion-controlled contributions,whilst the segregation of Fe with LiF is effectively alleviated by unique architecture.Moreover,during cycling,solid electrolyte interface film is reversibly formed/decomposed.Thus,this work is expected to offer rational exterior/interfacial designing strategies for metalbased samples.
