<br>BF3辅助打破LiNO3在碳酸盐电解液中的溶解度极限构建稳定的SEI膜用于无枝晶锂金属电池,Small

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BF3辅助打破LiNO3在碳酸盐电解液中的溶解度极限构建稳定的SEI膜用于无枝晶锂金属电池
Small ( IF 13.0 ) Pub Date : 2023-11-21 , DOI: 10.1002/smll.202308678
Jing Zhong ₁ , Zhixing Wang ₁ , Xiaoli Yi ₁ , Xinhai Li ₁ , Huajun Guo ₁ , Wenjie Peng ₁ , Jiexi Wang ₁ , Guochun Yan ₁

Affiliation

锂（Li）金属被认为是下一代锂二次电池的潜在候选者，但由于不可控的枝晶生长和低库仑效率（CE），其与广泛使用的碳酸盐基电解质的循环稳定性较差。 LiNO ₃是一种有效的添加剂，其有限的溶解度（<800 id=35>3（路易斯酸））被建议提高LiNO ₃在碳酸盐基电解质中的溶解度。溶解的NO ₃ ^-可以参与第一溶剂化壳层另外，通过差示电化学质谱分析证明_， NO ₃ ^-在Li^金属上优先被还原，从而导致PF ₆ ^-^和EC的分解。因此，可以获得包含Li ₃ N的SEI层，其表现出高的锂离子传导性，从而实现均匀且致密的Li沉积，从而可以提高具有BF ₃ /LiNO ₃的Li||Cu电池的CE。此外，低N/P比（3:1）的Li||LiFePO ₄在300次循环（约1500小时）后容量保持率高达90％，这一工作为掺入锂离子电池开辟了新的途径。 LiNO ₃转化为碳酸盐基电解质和高性能锂金属电池。

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Breaking the Solubility Limit of LiNO3 in Carbonate Electrolyte Assisted by BF3 to Construct a Stable SEI Film for Dendrite-Free Lithium Metal Batteries

Lithium (Li) metal is regarded as a potential candidate for the next generation of lithium secondary batteries, but it has poor cycling stability with the broadly used carbonate-based electrolytes due to the uncontrollable dendritic growth and low Coulombic efficiency (CE). LiNO₃ is an effective additive and its limited solubility (<800 ppm) in carbonate-based electrolytes is still a challenge, as reported. Herein, using BF₃ (Lewis acid) is proposed to enhance the solubility of LiNO₃ in carbonate-based electrolytes. The dissolved NO₃⁻ can be involved in the first solvation shell of Li⁺, reducing the coordination number of PF₆⁻ and EC (ethylene carbonate). In addition, the NO₃⁻ is proved to be preferentially reduced on Li metal by differential electrochemical mass spectrometry so that the decomposition of PF₆⁻ and EC is suppressed. Therefore, a SEI layer containing Li₃N can be obtained, which exhibits high lithium-ion conductivity, achieving even and dense Li deposits. Consequently, the CE of Li||Cu cell with BF₃/LiNO₃ can be increased to 98.07%. Moreover, the capacity retention of Li||LiFePO₄ with a low N/P ratio (3:1) is as high as 90% after 300 cycles (≈1500 h). This work paved a new way for incorporating LiNO₃ into carbonate-based electrolytes and high-performance lithium metal batteries.

更新日期：2023-11-21

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