Microstructures of surface layer (near diamond) of the metallic film from Fe Ni C system are composed of (Fe,Ni) 3C, (Fe,Ni) 23 C 6 and γ (Fe,Ni), from which it can be assumed that graphite isnt directly catalyzed ...Microstructures of surface layer (near diamond) of the metallic film from Fe Ni C system are composed of (Fe,Ni) 3C, (Fe,Ni) 23 C 6 and γ (Fe,Ni), from which it can be assumed that graphite isnt directly catalyzed into diamond through the film and there exists a transition phase (Fe,Ni) 3C that can decompose into diamond structure. AFM morphologies on the film/diamond interface are traces preserved after carbon groups moving from the film to diamond. The morphologies on the as grown diamond are similar to those on corresponding films, being spherical on (100) face and sawtooth like steps on (111) face. Diamond growth rates and temperature gradients in boundary layer of the molten film at HPHT result in morphology differences.展开更多
Sodium-ion batteries(SIBs),as the low-cost and large-scale energy storage devices,have attracted wide attention,but their capacity and cycle performance are limited by cathode materials.Here,P2-Na0.7MnO2.05microflakes...Sodium-ion batteries(SIBs),as the low-cost and large-scale energy storage devices,have attracted wide attention,but their capacity and cycle performance are limited by cathode materials.Here,P2-Na0.7MnO2.05microflakes with the diameter 500 nm to 1μm are synthesized by an improved solid-state reaction.The as-prepared P2-Na0.7MnO2.05microflakes exhibit excellent electrochemical performance when tested as a cathode material of SIBs.It delivers a considerably reversible capacity of 142.7 mA h g-1at a current density of 0.3C(1C=180 mA g-1)with a slow capacity decay to121.5 mA h g-1after 50 cycles.Even at a high current density of 2C,the P2-Na0.7MnO2.05microflakes still show a specific capacity of 88.9 mA h g-1with a capacity retention of 75%after 100 cycles.The above performance of Na0.7MnO2.05microflakes are better than Na0.7MnO2.05with large block morphology,which is mainly attributed to the lamellar morphology of P2-Na0.7MnO2.05alleviating structural deformation and accelerating reaction kinetics.This strategy will provide new opportunities to develop stable oxide cathodes for SIBs.展开更多
文摘Microstructures of surface layer (near diamond) of the metallic film from Fe Ni C system are composed of (Fe,Ni) 3C, (Fe,Ni) 23 C 6 and γ (Fe,Ni), from which it can be assumed that graphite isnt directly catalyzed into diamond through the film and there exists a transition phase (Fe,Ni) 3C that can decompose into diamond structure. AFM morphologies on the film/diamond interface are traces preserved after carbon groups moving from the film to diamond. The morphologies on the as grown diamond are similar to those on corresponding films, being spherical on (100) face and sawtooth like steps on (111) face. Diamond growth rates and temperature gradients in boundary layer of the molten film at HPHT result in morphology differences.
文摘Sodium-ion batteries(SIBs),as the low-cost and large-scale energy storage devices,have attracted wide attention,but their capacity and cycle performance are limited by cathode materials.Here,P2-Na0.7MnO2.05microflakes with the diameter 500 nm to 1μm are synthesized by an improved solid-state reaction.The as-prepared P2-Na0.7MnO2.05microflakes exhibit excellent electrochemical performance when tested as a cathode material of SIBs.It delivers a considerably reversible capacity of 142.7 mA h g-1at a current density of 0.3C(1C=180 mA g-1)with a slow capacity decay to121.5 mA h g-1after 50 cycles.Even at a high current density of 2C,the P2-Na0.7MnO2.05microflakes still show a specific capacity of 88.9 mA h g-1with a capacity retention of 75%after 100 cycles.The above performance of Na0.7MnO2.05microflakes are better than Na0.7MnO2.05with large block morphology,which is mainly attributed to the lamellar morphology of P2-Na0.7MnO2.05alleviating structural deformation and accelerating reaction kinetics.This strategy will provide new opportunities to develop stable oxide cathodes for SIBs.
