Data for the publication "MgB2Se4 Spinels (B = Sc, Y, Er, Tm) as Potential Mg-Ion Solid Electrolytes – Partial Ionic Conductivity and the Ion Migration Barrier"

Description Datasets Datasets are obtained from X-ray diffraction (XRD), Rietveld analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), chronopotentiometry (CP) and linear sweep voltammetry (LSV). Abstract The magnesium chalcogenide spinel MgSc~2~Se~4~ with high Mg-ion room-temperature conductivity has recently attracted interest as solid electrolyte for magnesium ion batteries. Its ionic/electronic mixed-conducting nature and the influence of the spinel composition on the conductivity and Mg^2+^ migration barrier are yet not well understood. Here, results from a combined experimental and computational study on four MgB~2~Se~4~ spinels (B = Sc, Y, Er, Tm) are presented. The room-temperature ionic conductivities (σ~ion~ = 2x10^–5^–7x10^–5^ S cm^–1^) of the spinels are accurately measured, as electron transport is effectively suppressed by purely Mg-ion conducting electrode interlayers. Using the same approach, reversible Mg plating/stripping as well as good electrochemical stability are achieved. Driven by the good accordance of the computationally and experimentally obtained Mg^2+^ migration barriers E~a~(th) and E~a~, respectively, further periodic density functional calculations are performed on the MgB~2~Se~4~ spinel system, revealing the role of trigonal distortion on the migration path geometry and E~a~(th). These findings provide deeper understanding how to reach small Mg^2+^ migration barriers E~a~ in the MgB~2~Se~4~ spinels.数据集描述 本数据集的数据来源于X射线衍射（X-ray diffraction, XRD）、里特维尔德精修分析（Rietveld analysis）、扫描电子显微镜（scanning electron microscopy, SEM）、能量色散X射线能谱（energy-dispersive X-ray spectroscopy, EDS）、透射电子显微镜（transmission electron microscopy, TEM）、核磁共振波谱法（nuclear magnetic resonance, NMR）、电化学阻抗谱（electrochemical impedance spectroscopy, EIS）、计时电流法（chronoamperometry, CA）、计时电位法（chronopotentiometry, CP）以及线性扫描伏安法（linear sweep voltammetry, LSV）。 摘要 具有高室温镁离子电导率的硫族镁尖晶石MgSc₂Se₄近年来作为镁离子电池固体电解质受到广泛关注。但其离子/电子混合导电特性，以及尖晶石组成对电导率与Mg²+迁移能垒的影响机制尚未得到充分阐释。本文报道了针对四种MgB₂Se₄尖晶石（B分别为Sc、Y、Er、Tm）开展的实验与计算联合研究成果。通过采用纯镁离子导电电极夹层有效抑制电子传输，我们准确测定了该系列尖晶石的室温离子电导率（σ_ion = 2×10^–5 ~ 7×10^–5 S·cm^–1）。采用相同实验策略，还实现了可逆的镁电镀/剥离过程，并获得了良好的电化学稳定性。鉴于计算与实验得到的Mg²+迁移能垒E_a(th)与E_a具有高度一致性，我们进一步对MgB₂Se₄尖晶石体系开展了周期性密度泛函计算，揭示了三角畸变对迁移路径几何结构与E_a(th)的调控作用。上述发现为如何调控MgB₂Se₄尖晶石中的Mg²+迁移能垒以获取更小能垒提供了更深入的认知。