A Sodium–Antimony–Telluride Intermetallic Allows Sodium‐Metal Cycling at 100% Depth of Discharge and as an Anode‐Free Metal Battery
A Sodium–Antimony–Telluride Intermetallic Allows Sodium‐Metal Cycling at 100% Depth of Discharge and as an Anode‐Free Metal Battery
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A%20钠—锑—碲化物%20金属间化合物%20允许%20钠—金属%20循环%20at%20100%%20深度%20of%20放电%20和%20as%20an%20阳极—自由%20金属%20电池
DOI：
10.1002/adma.202106005
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发表时间：
2021
影响因子：
29.4
通讯作者：
Mitlin, David
中科院分区：
文献类型：
--
作者：
Wang, Yixian;Dong, Hui;Katyal, Naman;Hao, Hongchang;Liu, Pengcheng;Celio, Hugo;Henkelman, Graeme;Watt, John;Mitlin, David
采用反复冷轧和折叠来制造分散在电化学活性钠金属中的钠-锑-碲化钠Na 2（Sb 2/6 Te 3/6Vac 1/6）的冶金复合材料，称为“NST-Na”。这种新的金属间化合物具有富空位的化学稳定的面心立方结构，并在广泛使用的碳酸盐和醚电解质中实现最先进的电化学性能。NST‐Na在1 mNaPF 6 in G2中实现100%的放电深度（DOD），在1 mA cm − 2时为15 mAh cm− 2，库仑效率（CE）为99.4%，可进行1000小时的电镀/剥离。采用NST-Na和Na 3V 2（PO 4）3（NVP）或硫阴极的钠金属电池（SMB）可显著提高能量、循环和CE（>99%）。具有NST集电体和NVP的无阳极电池每次循环获得0.23%的容量衰减。使用常规和低温显微镜（Cryo-EM）进行的成像和断层扫描表明，钠金属填充了自支撑亲钠NST骨架内部的开放空间，导致具有平坦表面的致密（无孔和无固体电解质界面（SEI））金属沉积物。基线Na存款由丝状枝晶和“死金属”组成，与孔隙和SEI混合。密度泛函理论计算表明，NST的独特性在于其表面上的Na原子（而不是簇）的热力学稳定性，导致平面润湿，以及其自身的稳定性，防止在循环过程中分解。
Repeated cold rolling and folding is employed to fabricate a metallurgical composite of sodium–antimony–telluride Na2(Sb2/6Te3/6Vac1/6) dispersed in electrochemically active sodium metal, termed “NST‐Na.” This new intermetallic has a vacancy‐rich thermodynamically stable face‐centered‐cubic structure and enables state‐of‐the‐art electrochemical performance in widely employed carbonate and ether electrolytes. NST‐Na achieves 100% depth‐of‐discharge (DOD) in 1mNaPF6in G2, with 15 mAh cm−2at 1 mA cm−2and Coulombic efficiency (CE) of 99.4%, for 1000 h of plating/stripping. Sodium‐metal batteries (SMBs) with NST‐Na and Na3V2(PO4)3(NVP) or sulfur cathodes give significantly improved energy, cycling, and CE (>99%). An anode‐free battery with NST collector and NVP obtains 0.23% capacity decay per cycle. Imaging and tomography using conventional and cryogenic microscopy (Cryo‐EM) indicate that the sodium metal fills the open space inside the self‐supporting sodiophilic NST skeleton, resulting in dense (pore‐free and solid electrolyte interphase (SEI)‐free) metal deposits with flat surfaces. The baseline Na deposit consists of filament‐like dendrites and “dead metal”, intermixed with pores and SEI. Density functional theory calculations show that the uniqueness of NST lies in the thermodynamic stability of the Na atoms (rather than clusters) on its surface that leads to planar wetting, and in its own stability that prevents decomposition during cycling.