Designing an asymmetric ether-like lithium salt to enable fast-cycling high-energy lithium metal batteries

Xia, Yingchun; Zhou, Pan; Kong, Xian; Tian, Jiekang; Zhang, Weili; Yan, Shuaishuai; Hou, Wenhui; Zhou, Hang-Yu; Dong, Hao; Chen, Xiaoxia; Wang, Peican; Xu, Ziang; Wan, Lei; Wang, Baoguo; Liu, Kai

doi:10.1038/s41560-023-01282-z

“…Lithium (Li) metal with a high theoretical capacity (3860 mAh g –1 ) and the lowest redox potential (−3.04 V vs the standard hydrogen electrode) is one of the most promising anode alternatives for next-generation rechargeable batteries with high energy density. , However, the industrialized carbonate-based liquid electrolytes are incompatible with the Li anode, thus resulting in an unstable solid electrolyte interphase (SEI), , limited cycle life, , and severe safety risks of electrolyte leakage and fires. , To tackle these dilemmas, replacing the flammable organic solvent with an all-solid-state electrolyte is a feasible way. , Great research efforts have been devoted to exploring solid polymer electrolytes (SPEs) due to their low density, excellent flexibility, and good processing compatibility with the current roll-to-roll technique for all-solid-state lithium metal batteries. , Up to now, the most widely studied and employed SPE is still the composite of poly(ethylene oxide) (PEO) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), whose ion transport behavior was found more than 40 years ago though the ionic conductivity was relatively low (∼10 –6 S cm –1 ). , During the following decades, efforts have been devoted to solve the problem of sluggish Li ion transport in the SPE, and a moderate ionic conductivity (∼10 –4 S cm –1 ) has already been achieved at room temperature by modifying polymer molecules, − optimizing electrolyte physical structures, − introducing organic plasticizers or inorganic fillers, etc. − However, the long-term cycling stability of all-solid-state lithium batteries with the LiTFSI-PEO SPE is still affected by the poor SPE/Li anode interface compatibility . This is mainly attributed to the low lithium ion transference number ( t + < 0.2) and weak film-forming ability on a Li metal anode of the LiTFSI salt. , It is well-known that LiTFSI exhibits high charge delocalization and ionic conductivity in SPEs .…”

Section: Introductionmentioning

confidence: 99%

“…Lithium (Li) metal with a high theoretical capacity (3860 mAh g −1 ) and the lowest redox potential (−3.04 V vs the standard hydrogen electrode) is one of the most promising anode alternatives for next-generation rechargeable batteries with high energy density. 1,2 However, the industrialized carbonatebased liquid electrolytes are incompatible with the Li anode, thus resulting in an unstable solid electrolyte interphase (SEI), 3,4 limited cycle life, 5,6 and severe safety risks of electrolyte leakage and fires. 7,8 To tackle these dilemmas, replacing the flammable organic solvent with an all-solid-state electrolyte is a feasible way.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Trihalogenated Aromatic Lithium Salt Induced Lithium Halide Rich Interface for Stable Cycling of All-Solid-State Lithium Batteries

Yan,

Liu,

Ou

et al. 2023

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Solid polymer electrolytes (SPEs) are the key components for all-solid-state lithium metal batteries with high energy density and intrinsic safety. However, the low lithium ion transference number (t + ) of a conventional SPE and its unstable electrolyte/electrode interface cannot guarantee longterm stable operation. Herein, asymmetric trihalogenated a r o m a t i c l i t h i u m s a l t s , i . e . , l i t h i u m ( 3 , 4 , 5trifluorobenzenesulfonyl)(trifluoromethanesulfonyl)imide (LiFFF) and lithium (4-bromo-3,5-difluorobenzenesulfonyl)-(trifluoromethanesulfonyl)imide (LiFBF), are synthesized for polymer electrolytes. They exhibit higher t + values and better compatibility with Li metal than conventional lithium bis-(trifluoromethanesulfonyl) imide (LiTFSI). Due to the trihalogenated aromatic anions, LiFFF-and LiFBF-based electrolytes are prone to generate an LiF-and LiBr-rich solid electrolyte interphase (SEI), therefore increasing the stability of the solid electrolyte/anode interface. Particularly, LiFBF could induce a LiF/LiBr hybrid SEI, where LiF shows a high Young's modulus and high surface energy for homogenizing Li ion flux and LiBr exhibits an extremely low Li ion diffusion barrier in the SEI layer. As a result, the Li/Li symmetric cells could remain stable for more than 1200 h without a short circuit and the LiFePO 4 / Li batteries showed superb electrochemical performance over 1200 cycles at 1 C. This work provides valuable insights from the perspective of lithium salt molecular structures for high-performance all-solid-state lithium metal batteries.

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“…[5] Among these steps, the metal-ion desolvation and ion diffusion in the solid electrolyte interphase (SEI) layers and anode materials are the main energy-consuming processes (Figure 1a), which contribute significantly to the sluggish mass transport kinetics. [6] In view of this revelation, the strategies of tailoring ideal metal-ion solvation structure, [7] interphase, [8] and ion transport channels in anode materials [9] are widely adopted to reduce the energy barrier of metal-ion transport. Especially for lithium (Li)-ion batteries, the electrolyte engineering is an effective method to regulate the Li-ion solvation structure.…”

Section: Introductionmentioning

confidence: 99%

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast‐Charging Lithium‐Ion Batteries

Ma,

Zhao,

Gao

et al. 2023

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The fast‐charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I‐PAN) anode that can boost the bulk/interphase lithium (Li)‐ion diffusion kinetics and accelerate Li‐ion desolvation process to realize high‐performance fast‐charging Li‐ion batteries. The iodine immobilized in I‐PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI‐rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self‐induced by the interfacial nucleophilic substitution of PF6‐ not only promote the Li‐ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast‐charging conditions. Consequently, the I‐PAN anode exhibits a high capacity of 228.5 mA h g‐1 (39% of capacity at 0.5 A g‐1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g‐1. The I‐PAN||LiNi0.8Co0.1Mn0.1O2 full cell shows excellent fast‐charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C = 180 mA g‐1). We also demonstrate high‐performance fast‐charging sodium‐ion batteries using I‐PAN anodes.

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“…[5] Among these steps, the metal-ion desolvation and ion diffusion in the solid electrolyte interphase (SEI) layers and anode materials are the main energy-consuming processes (Figure 1a), which contribute significantly to the sluggish mass transport kinetics. [6] In view of this revelation, the strategies of tailoring ideal metal-ion solvation structure, [7] interphase, [8] and ion transport channels in anode materials [9] are widely adopted to reduce the energy barrier of metal-ion transport. Especially for lithium (Li)-ion batteries, the electrolyte engineering is an effective method to regulate the Li-ion solvation structure.…”

Section: Introductionmentioning

confidence: 99%

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast‐Charging Lithium‐Ion Batteries

Ma,

Zhao,

Gao

et al. 2023

Angewandte Chemie

1

0

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The fast‐charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I‐PAN) anode that can boost the bulk/interphase lithium (Li)‐ion diffusion kinetics and accelerate Li‐ion desolvation process to realize high‐performance fast‐charging Li‐ion batteries. The iodine immobilized in I‐PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI‐rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self‐induced by the interfacial nucleophilic substitution of PF6‐ not only promote the Li‐ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast‐charging conditions. Consequently, the I‐PAN anode exhibits a high capacity of 228.5 mA h g‐1 (39% of capacity at 0.5 A g‐1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g‐1. The I‐PAN||LiNi0.8Co0.1Mn0.1O2 full cell shows excellent fast‐charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C = 180 mA g‐1). We also demonstrate high‐performance fast‐charging sodium‐ion batteries using I‐PAN anodes.

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Designing an asymmetric ether-like lithium salt to enable fast-cycling high-energy lithium metal batteries

Cited by 124 publications

References 40 publications

Asymmetric Trihalogenated Aromatic Lithium Salt Induced Lithium Halide Rich Interface for Stable Cycling of All-Solid-State Lithium Batteries

Asymmetric Trihalogenated Aromatic Lithium Salt Induced Lithium Halide Rich Interface for Stable Cycling of All-Solid-State Lithium Batteries

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast‐Charging Lithium‐Ion Batteries

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast‐Charging Lithium‐Ion Batteries

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