采用固相法、醋酸盐燃烧法、氢氧化物共沉淀、草酸盐共沉淀的方法制备P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_2钠离子电池层状正极材料。通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)和电化学手段等不同测试方法,对比不同方法对合成材料结构、...采用固相法、醋酸盐燃烧法、氢氧化物共沉淀、草酸盐共沉淀的方法制备P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_2钠离子电池层状正极材料。通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)和电化学手段等不同测试方法,对比不同方法对合成材料结构、形貌及电化学性能的影响。实验结果表明,用氢氧化物共沉淀法结合固相反应所制备的正极材料具有更优的电化学性能。该材料在0.1 C倍率,2.0~4.0 V电压范围下首次放电比容量为87.9 m Ah/g。1.0 C首次放电比容量为72.3 m Ah/g,50次循环后的容量保持率为108.0%。展开更多
We present a systematic first-principles based study on the formation of coherent L12-phase nanoparticles in dilute Al-Sc-Zr alloys.Bulk structures and properties,solute substitution,interface formation energies,and i...We present a systematic first-principles based study on the formation of coherent L12-phase nanoparticles in dilute Al-Sc-Zr alloys.Bulk structures and properties,solute substitution,interface formation energies,and interfacial coherent strains are all calculated.Nucleation modeling and relevant energetic calculations are performed on various possible structures of L12-phase nano-precipitates,i.e.individual L12-Al3Sc and L12-Al3Zr,homogeneous L12-Al3(ScxZr1-x)and the core-shelled L12-Al3Sc(Al3Zr)and L12-Al3Zr(Al3Sc).The following insights are obtained.Matrix-dissolved Sc or Zr strongly prefers to substitute the X sublattice sites in L12-Al3X(X=Zr or Sc),while the inter-substitution between L12-Al3Sc and Al3Zr is only weakly feasible.The cube-on-cube orientation with the(100)/(100)contacting facets is the most energy favored for the Al/Al3Sc(L12),Al/Al3Zr(L12)and Al3Sc(L12)/Al3Zr(L12)interfaces.All these interfaces are highly coherent,with fairly low formation energy.And particularly,the Al3Sc(L12)/Al3Zr(L12)interface has essentially zero formation energy.Ternary L12-Al3(ScxZr1-x)precipitates tend to form a Al3Sc-based core and Al3Zr-based shell structure,with a relatively sharp inner interface of Al3Sc(L12)/Al3Zr(L12).This core-shelled structure becomes energetically more favorable for the particle size R>1–2 nm.The potential influence of the Sc/Zr ratio and temperature on the relative stabilities of L12-phases in Al is also evaluated and discussed.展开更多
文摘采用固相法、醋酸盐燃烧法、氢氧化物共沉淀、草酸盐共沉淀的方法制备P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_2钠离子电池层状正极材料。通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)和电化学手段等不同测试方法,对比不同方法对合成材料结构、形貌及电化学性能的影响。实验结果表明,用氢氧化物共沉淀法结合固相反应所制备的正极材料具有更优的电化学性能。该材料在0.1 C倍率,2.0~4.0 V电压范围下首次放电比容量为87.9 m Ah/g。1.0 C首次放电比容量为72.3 m Ah/g,50次循环后的容量保持率为108.0%。
基金financial support from the National Natural Science Foundation of China (No. 51471189)the Key Research and Development Projects of Shandong Province (No. 2017GGX20130)the National Basic Research Program of China (sub-contract No. 2014CB644001-2)
文摘We present a systematic first-principles based study on the formation of coherent L12-phase nanoparticles in dilute Al-Sc-Zr alloys.Bulk structures and properties,solute substitution,interface formation energies,and interfacial coherent strains are all calculated.Nucleation modeling and relevant energetic calculations are performed on various possible structures of L12-phase nano-precipitates,i.e.individual L12-Al3Sc and L12-Al3Zr,homogeneous L12-Al3(ScxZr1-x)and the core-shelled L12-Al3Sc(Al3Zr)and L12-Al3Zr(Al3Sc).The following insights are obtained.Matrix-dissolved Sc or Zr strongly prefers to substitute the X sublattice sites in L12-Al3X(X=Zr or Sc),while the inter-substitution between L12-Al3Sc and Al3Zr is only weakly feasible.The cube-on-cube orientation with the(100)/(100)contacting facets is the most energy favored for the Al/Al3Sc(L12),Al/Al3Zr(L12)and Al3Sc(L12)/Al3Zr(L12)interfaces.All these interfaces are highly coherent,with fairly low formation energy.And particularly,the Al3Sc(L12)/Al3Zr(L12)interface has essentially zero formation energy.Ternary L12-Al3(ScxZr1-x)precipitates tend to form a Al3Sc-based core and Al3Zr-based shell structure,with a relatively sharp inner interface of Al3Sc(L12)/Al3Zr(L12).This core-shelled structure becomes energetically more favorable for the particle size R>1–2 nm.The potential influence of the Sc/Zr ratio and temperature on the relative stabilities of L12-phases in Al is also evaluated and discussed.
