Boosting ultra-fast charging in lithium metal batteries through enhanced solvent–anion interaction via conjugation effect,Energy & Environmental Science

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Boosting ultra-fast charging in lithium metal batteries through enhanced solvent–anion interaction via conjugation effect
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2024-08-08 , DOI: 10.1039/d4ee00391h
Jialin Wang _{1,

2} , Lin Xie _{1,

2} , Wanbao Wu _{1,

3,

4} , Yihong Liang _{1,

2} , Miaomiao Cao _{1,

2} , Chaochao Gao _{1,

2} , Yiyang Bo _{1,

2} , Jichuan Zhang _{1,

2} , Jiaheng Zhang _{1,

2}

Affiliation

In pursuit of higher energy density, adopting a lithium metal anode holds promise for the evolving battery technology. Nevertheless, practical obstacles persist, including explosion hazards, restricted fast charging (>5C), and lithium metal compatibility issues. To tackle these challenges, we devised a non-flammable deep eutectic electrolyte (DEE) comprising lithium bisfluorosulfonimide (LiFSI) and prop-1-ene-1,3-sultone (PES). This DEE demonstrates exceptional attributes, including near 98.76% Coulombic efficiency and a high ionic conductivity of 1.96 mS cm⁻¹. We found that the electron-absorbing effect of the double-bonded structure enhances the interactions between PES and FSI⁻, releasing more free lithium ions and boosting the Li⁺ transference number of 0.78. Our engineered DEE fosters the formation of a robust organic–inorganic gradient solid electrolyte interphase (SEI) with a surface layer rich in organic species and an inner layer rich in inorganic species. The high Li⁺ transfer number and stable SEI together enable ultra-fast charging and sustained cycling, with 81.32% capacity retention after 1000 cycles at 10C in the LiFePO₄‖DEE‖Li battery. Meanwhile, the mechanistic reasons behind fast charging performance are elaborated by theoretical calculations, and its practical applicability is underscored through successful implementation in pouch cells with high loading and 30 μm of Li metal.

中文翻译：

通过共轭效应增强溶剂-阴离子相互作用，促进锂金属电池的超快速充电

为了追求更高的能量密度，采用锂金属负极为不断发展的电池技术带来了希望。然而，实际障碍仍然存在，包括爆炸危险、限制快速充电（>5C）和锂金属兼容性问题。为了应对这些挑战，我们设计了一种由双氟磺酰亚胺锂（LiFSI）和丙-1-烯-1,3-磺内酯（PES）组成的不易燃的深共晶电解质（DEE）。这种 DEE 表现出卓越的特性，包括接近 98.76% 的库仑效率和 1.96 mS ^cm-1 的高离子电导率。我们发现双键结构的电子吸收作用增强了 PES 和 FSI⁻ 之间的相互作用，释放出更多的自由锂离子，并使 Li⁺ 转移数提高到 0.78。我们设计的 DEE 促进了稳健的有机-无机梯度固体电解质界面（SEI）的形成，其表层富含有机物质，内层富含无机物质。高 Li⁺ 传输数和稳定的 SEI 共同实现了超快速充电和持续循环，在 LiFePO81.32‖DEE‖Li 电池中，在 10C 下循环 1000 次后，容量保持率为 4%。同时，通过理论计算阐述了快速充电性能背后的机制原因，并通过在高负载和 30 μm 锂金属的软包电池中成功实施强调了其实际适用性。

更新日期：2024-08-08

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