Harrison Katharine L, Merrill Laura C, Long Daniel Martin, Randolph Steven J, Goriparti Subrahmanyam, Christian Joseph, Warren Benjamin, Roberts Scott A, Harris Stephen J, Perry Daniel L, Jungjohann Katherine L
Nanoscale Sciences, Sandia National Laboratories, Albuquerque, NM 87123, USA.
Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87123, USA.
iScience. 2021 Nov 1;24(12):103394. doi: 10.1016/j.isci.2021.103394. eCollection 2021 Dec 17.
Li metal anodes are enticing for batteries due to high theoretical charge storage capacity, but commercialization is plagued by dendritic Li growth and short circuits when cycled at high currents. Applied pressure has been suggested to improve morphology, and therefore performance. We hypothesized that increasing pressure would suppress dendritic growth at high currents. To test this hypothesis, here, we extensively use cryogenic scanning electron microscopy to show that varying the applied pressure from 0.01 to 1 MPa has little impact on Li morphology after one deposition. We show that pressure improves Li density and preserves Li inventory after 50 cycles. However, contrary to our hypothesis, pressure dendritic growth through the separator, short circuits. Therefore, we suspect Li inventory is better preserved in cells cycled at high pressure because the shorts carry a larger portion of the current, with less being carried by electrochemical reactions that slowly consume Li inventory.
锂金属阳极因具有高理论电荷存储容量而对电池具有吸引力，但在高电流循环时，商业化受到枝晶锂生长和短路问题的困扰。有人提出施加压力来改善锂的形态，从而提高性能。我们假设增加压力会抑制高电流下的枝晶生长。为了验证这一假设，在此，我们广泛使用低温扫描电子显微镜表明，在一次沉积后，将施加压力从0.01 MPa变化到1 MPa对锂的形态几乎没有影响。我们表明，压力可提高锂密度并在50次循环后保持锂存量。然而，与我们的假设相反，压力会导致枝晶生长穿过隔膜，从而引发短路。因此，我们怀疑在高压下循环的电池中锂存量能得到更好的保存，因为短路传导了较大一部分电流，而通过缓慢消耗锂存量的电化学反应传导的电流较少。
