Semi-solid alkali metal electrodes enabling high critical current densities in solid electrolyte batteries
Semi-solid alkali metal electrodes enabling high critical current densities in solid electrolyte batteries
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DOI：
10.1038/s41560-021-00786-w
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发表时间：
2021-03-15
期刊：
影响因子：
56.7
通讯作者：
Chiang, Yet-Ming
中科院分区：
文献类型：
--
作者：
Park, Richard J. -Y.;Eschler, Christopher M.;Chiang, Yet-Ming
对更高能量密度可充电电池的需求引起了人们对与固体电解质配对的碱金属电极的兴趣。然而，低电流密度下的金属渗透和电解质破裂已成为根本障碍。在这里，我们表明，对于 Li-Na-K 系统中的纯金属，临界电流密度与机械变形阻力成反比。此外，我们展示了两种电极结构，其中液相的存在可以实现高电流密度，同时保留固体电极的形状保持和封装优势。首先，双相Na-K 合金的K+ 临界电流密度（使用K-beta ''-Al2O3 电解质）超过15 mA cm(-2)。其次，在Li金属和Li6.75La3Zr1.75Ta0.25O12固体电解质之间引入Na-K液体润湿界面膜，使临界电流密度加倍，并允许在超过3.5 mAh cm(-2)的面积容量下循环。这些设计方法有望克服迄今为止限制固态金属电池性能的电化学机械稳定性问题。在电池中使用金属阳极的一个挑战是它们无法维持结构稳定性，尤其是在高电流下。在这里，作者研究了金属阳极的电化学机械性能，并在实际相关条件下展示了一种有效的半固体电极方法。
The need for higher energy-density rechargeable batteries has generated interest in alkali metal electrodes paired with solid electrolytes. However, metal penetration and electrolyte fracture at low current densities have emerged as fundamental barriers. Here we show that for pure metals in the Li-Na-K system, the critical current densities scale inversely to mechanical deformation resistance. Furthermore, we demonstrate two electrode architectures in which the presence of a liquid phase enables high current densities while it preserves the shape retention and packaging advantages of solid electrodes. First, biphasic Na-K alloys show K+ critical current densities (with the K-beta ''-Al2O3 electrolyte) that exceed 15 mA cm(-2). Second, introducing a wetting interfacial film of Na-K liquid between Li metal and Li6.75La3Zr1.75Ta0.25O12 solid electrolyte doubles the critical current density and permits cycling at areal capacities that exceed 3.5 mAh cm(-2). These design approaches hold promise for overcoming electrochemomechanical stability issues that have heretofore limited the performance of solid-state metal batteries.A challenge with the use of metal anodes in batteries is their inability to sustain structural stability, especially at high currents. Here the authors examine electrochemomechanical properties of metal anodes and demonstrate an effective semi-solid electrode approach at practically relevant conditions.