基于二氟苯的局部浓缩离子液体电解质使富镍阴极锂金属电池的稳定循环成为可能,Advanced Energy Materials

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基于二氟苯的局部浓缩离子液体电解质使富镍阴极锂金属电池的稳定循环成为可能
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2022-05-18 , DOI: 10.1002/aenm.202200862
Xu Liu _{1,

2} , Alessandro Mariani _{1,

2} , Thomas Diemant _{1,

2} , Maria Enrica Di Pietro ₃ , Xu Dong _{1,

2} , Matthias Kuenzel _{1,

2} , Andrea Mele ₃ , Stefano Passerini _{1,

2}

Affiliation

具有富镍阴极的锂金属电池 (LMB) 是下一代高能电池的有希望的候选者。然而，高反应性电极通常与传统电解质表现出较差的界面相容性，导致循环性能有限。本文设计了一种由双（氟磺酰基）亚胺锂（LiFSI）、1-乙基-3-甲基咪唑鎓双（氟磺酰基）亚胺（EmimFSI）和1,2-二氟苯（dFBn）组成的局部浓缩离子液体电解质（LCILE）。来克服这一挑战。作为助溶剂，dFBn 不仅可以促进锂^离子在仅基于离子液体的电解质中的传输，而且对锂金属负极 (LMA) 和 LiNi _0.8 Mn _{0.1上的电极/电解质界面 (EEI) 也有有益的影响。}Co _0.1 O ₂ (NMC811) 阴极。因此，开发的 LCILE 能够实现 LMA 的无枝晶循环，在 0.5 mA cm ^-2时库仑效率 (CE) 高达 99.57%，并且在 C/3 充电时 Li/NMC811 电池 (4.4 V) 的循环高度稳定，并且1 C 放电 (1 C = 2 mA cm ^-2 ) 500 次循环，容量保持率为 93%。相比之下，不含 dFBn 的电解液实现了锂剥离/电镀 CE，而在相同条件下，Li/NMC811 电池的容量保持率分别仅为 98.22% 和 16%。对配位结构、促进的 Li ⁺传输和 EEI 特性的深入了解为进一步开发用于长寿命、高能 LMB 的（基于 IL 的）电解质提供了必不可少的基本信息。

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Difluorobenzene-Based Locally Concentrated Ionic Liquid Electrolyte Enabling Stable Cycling of Lithium Metal Batteries with Nickel-Rich Cathode

Lithium metal batteries (LMBs) with nickel-rich cathodes are promising candidates for next-generation, high-energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consisting of lithium bis(fluorosulfonyl)imide (LiFSI), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EmimFSI), and 1,2-difluorobenzene (dFBn) is designed to overcome this challenge. As a cosolvent, dFBn not only promotes the Li⁺ transport with respect to the electrolyte based on the ionic liquid only, but also has beneficial effects on the electrode/electrolyte interphases (EEIs) on lithium metal anodes (LMAs) and LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) cathodes. As a result, the developed LCILE enables dendrite-free cycling of LMAs with a coulombic efficiency (CE) up to 99.57% at 0.5 mA cm⁻² and highly stable cycling of Li/NMC811 cells (4.4 V) at C/3 charge and 1 C discharge (1 C = 2 mA cm⁻²) for 500 cycles with a capacity retention of 93%. In contrast, the dFBn-free electrolyte achieves lithium stripping/plating CE, and the Li/NMC811 cells’ capacity retention of only 98.22% and 16%, respectively under the same conditions. The insight into the coordination structure, promoted Li⁺ transport, and EEI characteristics gives fundamental information essential for further developing (IL-based) electrolytes for long-life, high-energy LMBs.

更新日期：2022-05-18

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