Dry solid polymer electrolytes (SPEs), particularly those based on poly(ethylene oxide) (PEO), hold significant potential for advancing solid-state Li-metal battery (LMB) technology. Despite extensive research over the years, a comprehensive evaluation of Coulombic efficiency (CE), deposit stability, and cycle life for reversible Li metal electrodeposition in SPE-based cells is still lacking. In this study, we systematically assess the effect of cycling conditions on the CE of Li|SPE|Cu half cells and provide a thorough examination of different electrolyte chemistries, highlighting and explaining their performance across various parameters. While the efficiency of the PEO-based SPEs still falls short of the efficiency benchmark set by liquid and gel electrolytes, we demonstrated >95% CE with Lithium bis(fluorosulfonyl)imide (LiFSI)-based SPEs, surpassing previous reports for dry SPEs in a Li|SPE|Cu cells, this result marks a significant breakthrough. Furthermore, our findings highlight the critical impact of the Li-SPE interphase on these performance metrics. The LiFSI-based SPE forms a Li-rich, high-conductivity interphase, which not only enhances efficiency but also improves cycle life and Li deposit stability. These results underscore the importance of selecting the right polymer electrolyte chemistry and concentration to enhance SPE performance.

中文翻译：

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提高锂金属电沉积在干固态聚合物电解质中的效率、稳定性和循环寿命


干固体聚合物电解质 （SPE），尤其是基于聚环氧乙烷 （PEO） 的 SPE，在推进固态锂金属电池 （LMB） 技术方面具有巨大潜力。尽管多年来进行了广泛的研究，但仍然缺乏对基于 SPE 的电池中可逆锂金属电沉积的库仑效率 （CE）、沉积稳定性和循环寿命的全面评估。在这项研究中，我们系统地评估了循环条件对 Li|SPE|Cu 半电池，并对不同的电解质化学成分进行了全面检查，突出并解释了它们在各种参数中的性能。虽然基于 PEO 的 SPE 的效率仍低于液体和凝胶电解质设定的效率基准，但我们证明了基于双（氟磺酰基）酰亚胺锂 （LiFSI） 的 SPE 的 >95% CE，超过了之前关于 Li|SPE|Cu 电池，这一结果标志着重大突破。此外，我们的研究结果强调了 Li-SPE 界面对这些性能指标的关键影响。基于 LiFSI 的 SPE 形成富锂、高电导率的界面，这不仅提高了效率，还提高了循环寿命和锂沉积稳定性。这些结果强调了选择正确的聚合物电解质化学成分和浓度对提高 SPE 性能的重要性。