Synergy of an In Situ-Polymerized Electrolyte and a Li3N–LiF-Reinforced Interface Enables Long-Term Operation of Li-Metal Batteries,ACS Applied Materials & Interfaces

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Synergy of an In Situ-Polymerized Electrolyte and a Li3N–LiF-Reinforced Interface Enables Long-Term Operation of Li-Metal Batteries
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-10-26 , DOI: 10.1021/acsami.2c14575
Xuezhi Zhang ₁ , Guixia Gao ₁ , Wei Wang ₁ , Jin Wang ₁ , Lina Wang ₁ , Tianxi Liu _{1,

2}

Affiliation

The long-term operation of a Li-metal anode remains a great challenge due to the severe dendrite growth in an organic liquid electrolyte. To protect a Li-anode surface from continuous corrosion by an electrolyte, a consistent and robust solid electrolyte interface (SEI) is an essential prerequisite. This work proposes a secure gel polymer electrolyte, which is in situ constructed via a facile polymerization process of vinylidene carbonate inside Li-metal batteries. The liquid components that are not involved in polymerization are well entrapped in the poly(vinyl carbonate) framework, leading to a high oxidative stability of up to 4.5 V (vs Li/Li⁺). A Li₃N–LiF-reinforced SEI resulting from the reduction of fluoroethylene carbonate and lithium nitrate additives has a synergistic effect on the suppression of Li-dendrite growth. The densely packed Li deposition behavior is revealed by in situ/ex situ microscopic observations. Steady cycling of over 2500 h with a relatively low voltage hysteresis is achieved by the Li||Li symmetric cells. A Coulombic efficiency above 96% upon long-term cycling is available for the asymmetric Li||Cu cells. The smooth operation of batteries with commercial LiFePO₄ cathodes further indicates that the SEI with homogeneity in composition and structure prompts Li deposition with alleviative dendrites.

中文翻译：

原位聚合电解质和 Li3N-LiF 增强界面的协同作用使锂金属电池能够长期运行

由于有机液体电解质中严重的枝晶生长，锂金属负极的长期运行仍然是一个巨大的挑战。为了保护锂阳极表面免受电解质的持续腐蚀，一致且坚固的固体电解质界面（SEI）是必不可少的先决条件。这项工作提出了一种安全的凝胶聚合物电解质，它是通过锂金属电池内碳酸亚乙烯酯的简单聚合过程原位构建的。不参与聚合的液体组分被很好地捕获在聚碳酸乙烯酯骨架中，从而实现高达 4.5 V（相对于 Li/Li ⁺ ）的高氧化稳定性。由氟代碳酸亚乙酯和硝酸锂添加剂还原产生的Li ₃ N-LiF增强SEI对抑制锂枝晶生长具有协同作用。通过原位/非原位显微镜观察揭示了密集的锂沉积行为。 Li||Li 对称电池实现了超过 2500 小时的稳定循环，且电压滞后相对较低。非对称 Li||Cu 电池在长期循环后库仑效率可达到 96% 以上。采用商用LiFePO ₄正极的电池的平稳运行进一步表明，成分和结构均质的SEI可促进Li沉积并减轻枝晶。

更新日期：2022-10-26

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