Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States.
J Am Chem Soc. 2016 Nov 30;138(47):15443-15450. doi: 10.1021/jacs.6b08730. Epub 2016 Nov 16.
The widespread implementation of high-energy-density lithium metal batteries has long been fettered by lithium dendrite-related failure. Here we report a new strategy to address the issue of dendrite growth by a polyimide-coating layer with vertical nanoscale channels of high aspect ratio. Smooth, granular lithium metal was deposited on the modified electrode instead of typical filamentary growths. In a comparison with the bare planar electrode, the modified electrode achieved greatly enhanced Coulombic efficiency and longer cycle life. Homogeneous Li flux distribution above the modified electrode from the nanochannel confinement can account for a uniform Li nucleation and a nondendrite growth. We also demonstrated that the polyimide coating with microscale pores loses the confinement effects and fails to suppress lithium dendrites. This strategy of spatially defined lithium growth in vertical-aligned nanochannels provides a novel approach and a significant step toward stabilizing Li metal anodes.
高能量密度锂金属电池的广泛应用长期以来一直受到与锂枝晶相关的失效问题的束缚。在这里，我们报告了一种新策略，通过具有高纵横比的垂直纳米通道的聚酰亚胺涂层来解决枝晶生长的问题。在改性电极上沉积了光滑的、颗粒状的锂金属，而不是典型的丝状生长。与裸平面电极相比，改性电极实现了更高的库仑效率和更长的循环寿命。在改性电极上方的纳米通道限域作用下，均匀的 Li 通量分布可以导致均匀的 Li 成核和无枝晶生长。我们还证明了具有微尺度孔的聚酰亚胺涂层失去了限域作用，无法抑制锂枝晶。这种在垂直排列的纳米通道中空间限定锂生长的策略为稳定锂金属负极提供了一种新的方法和重要的步骤。
