scholarly journals Single-ion conducting polymer electrolyte for Li||LiNi0.6Mn0.2Co0.2O2 batteries—impact of the anodic cutoff voltage and ambient temperature

2021 ◽  
Author(s):  
Dominik Steinle ◽  
Zhen Chen ◽  
Huu-Dat Nguyen ◽  
Matthias Kuenzel ◽  
Cristina Iojoiu ◽  
...  
Keyword(s):  
Energy Density ◽  
Polymer Electrolyte ◽  
Coulombic Efficiency ◽  
Ethylene Carbonate ◽  
Active Material ◽  
Rate Capability ◽  
Lithium Metal ◽  
Lithium Metal Battery ◽  
The Impact ◽  
Battery Cells

AbstractPolymer-based electrolytes potentially enable enhanced safety and increased energy density of lithium-metal batteries employing high capacity, transition metal oxide–positive electrodes. Herein, we report the investigation of lithium-metal battery cells comprising Li[Ni0.6Mn0.2Co0.2]O2 as active material for the positive electrode and a poly(arylene ether sulfone)-based single-ion conductor as the electrolyte incorporating ethylene carbonate (EC) as selectively coordinating molecular transporter. The resulting lithium-metal battery cells provide very stable cycling for more than 300 cycles accompanied by excellent average Coulombic efficiency (99.95%) at an anodic cutoff potential of 4.2 V. To further increase the achievable energy density, the stepwise increase to 4.3 V and 4.4 V is herein investigated, highlighting that the polymer electrolyte offers comparable cycling stability, at least, as common liquid organic electrolytes. Moreover, the impact of temperature and the EC content on the rate capability is evaluated, showing that the cells with a higher EC content offer a capacity retention at 2C rate equal to 61% of the capacity recorded at 0.05 C at 60 °C.

scholarly journals Leveraging Cation Identity to Engineer Solid Electrolyte Interphases for Rechargeable Lithium Metal Anodes

2020 ◽  
Author(s):  
Richard May ◽  
Yumin Zhang ◽  
Steven R. Denny ◽  
Venkatasubramanian Viswanathan ◽  
Lauren Marbella
Keyword(s):  
Solid Electrolyte ◽  
Density Functional ◽  
Coulombic Efficiency ◽  
Ethylene Carbonate ◽  
Solid Electrolyte Interphase ◽  
Spectroscopic Characterization ◽  
Lithium Metal ◽  
Lithium Metal Anodes ◽  
The Impact ◽  
Metal Anodes

<p>Lithium metal anodes enable substantially higher energy density than current technologies for Li batteries. However, rechargeable Li metal anodes suffer from low Coulombic efficiency (loss of electrochemically active Li), leading to poor cycle life and safety. Engineering the electrolyte formulation to form a stable, well-functioning solid electrolyte interphase (SEI) is a promising approach to improving these performance figures of merit. While design rules have been established for selecting electrolyte solvents and salt anions to establish a more robust SEI, the impact of altering cation identity is not well understood. In this work, we demonstrate that alkali metal additives (here, K<sup>+</sup>) alter SEI composition and thickness. Through post-mortem elemental analyses, we show that K<sup>+</sup> ions do not directly participate in metal electrodeposition, but rather modify the chemical and electrochemical reactivity of the electrode-electrolyte interface. Through a combination of quantitative nuclear magnetic resonance (NMR) spectroscopic characterization and density functional theory (DFT) simulations, we show that decomposition of electrolyte solvent molecules, ethylene carbonate (EC) and dimethyl carbonate (DMC), at the lithium metal surface is suppressed in the presence of a K<sup>+</sup> additive. We attribute this to K<sup>+</sup> being a softer cation compared to Li<sup>+</sup>, leading to preferred pair formation between K<sup>+</sup> and the soft base carbonates, and thus increased salt-solvent coordination. Electrolyte cation engineering is an underexplored strategy to control the SEI, and we believe that the mechanistic understanding and insight developed in this work will spur further investigation of this promising approach.</p>

scholarly journals Leveraging Cation Identity to Engineer Solid Electrolyte Interphases for Rechargeable Lithium Metal Anodes

2020 ◽  
Author(s):  
Richard May ◽  
Yumin Zhang ◽  
Steven R. Denny ◽  
Venkatasubramanian Viswanathan ◽  
Lauren Marbella
Keyword(s):  
Solid Electrolyte ◽  
Density Functional ◽  
Coulombic Efficiency ◽  
Ethylene Carbonate ◽  
Solid Electrolyte Interphase ◽  
Spectroscopic Characterization ◽  
Lithium Metal ◽  
Lithium Metal Anodes ◽  
The Impact ◽  
Metal Anodes

<p>Lithium metal anodes enable substantially higher energy density than current technologies for Li batteries. However, rechargeable Li metal anodes suffer from low Coulombic efficiency (loss of electrochemically active Li), leading to poor cycle life and safety. Engineering the electrolyte formulation to form a stable, well-functioning solid electrolyte interphase (SEI) is a promising approach to improving these performance figures of merit. While design rules have been established for selecting electrolyte solvents and salt anions to establish a more robust SEI, the impact of altering cation identity is not well understood. In this work, we demonstrate that alkali metal additives (here, K<sup>+</sup>) alter SEI composition and thickness. Through post-mortem elemental analyses, we show that K<sup>+</sup> ions do not directly participate in metal electrodeposition, but rather modify the chemical and electrochemical reactivity of the electrode-electrolyte interface. Through a combination of quantitative nuclear magnetic resonance (NMR) spectroscopic characterization and density functional theory (DFT) simulations, we show that decomposition of electrolyte solvent molecules, ethylene carbonate (EC) and dimethyl carbonate (DMC), at the lithium metal surface is suppressed in the presence of a K<sup>+</sup> additive. We attribute this to K<sup>+</sup> being a softer cation compared to Li<sup>+</sup>, leading to preferred pair formation between K<sup>+</sup> and the soft base carbonates, and thus increased salt-solvent coordination. Electrolyte cation engineering is an underexplored strategy to control the SEI, and we believe that the mechanistic understanding and insight developed in this work will spur further investigation of this promising approach.</p>

Ionic liquid functionalized electrospun gel polymer electrolyte for use in a high-performance lithium metal battery

2018 ◽  
Vol 6 (38) ◽  
pp. 18479-18487 ◽  
Author(s):  
Yuanyuan Cheng ◽  
Lan Zhang ◽  
Song Xu ◽  
Haitao Zhang ◽  
Baozeng Ren ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Polymer Electrolyte ◽  
High Performance ◽  
Gel Polymer Electrolyte ◽  
Rate Capability ◽  
Lithium Metal ◽  
Lithium Deposition ◽  
Lithium Metal Battery

The reported novel gel polymer electrolyte can stabilize lithium deposition, thus enhancing the safety and rate capability by reducing the anion mobility in Li/LiNi0.5Mn1.5O4 cells.

Ultrathin and Non‐Flammable Dual‐Salt Polymer Electrolyte for High‐Energy‐Density Lithium‐Metal Battery

2021 ◽  
pp. 2010261
Author(s):  
Xidong Lin ◽  
Jing Yu ◽  
Mohammed B. Effat ◽  
Guodong Zhou ◽  
Matthew J. Robson ◽  
...  
Keyword(s):  
Energy Density ◽  
Polymer Electrolyte ◽  
High Energy ◽  
High Energy Density ◽  
Lithium Metal ◽  
Lithium Metal Battery

scholarly journals Leveraging Cation Identity to Engineer Solid Electrolyte Interphases for Rechargeable Lithium Metal Anodes

2020 ◽  
Author(s):  
Richard May ◽  
Yumin Zhang ◽  
Steven R. Denny ◽  
Venkatasubramanian Viswanathan ◽  
Lauren Marbella
Keyword(s):  
Solid Electrolyte ◽  
Density Functional ◽  
Coulombic Efficiency ◽  
Ethylene Carbonate ◽  
Solid Electrolyte Interphase ◽  
Spectroscopic Characterization ◽  
Lithium Metal ◽  
Lithium Metal Anodes ◽  
The Impact ◽  
Metal Anodes

<p>Lithium metal anodes enable substantially higher energy density than current technologies for Li batteries. However, rechargeable Li metal anodes suffer from low Coulombic efficiency (loss of electrochemically active Li), leading to poor cycle life and safety. Engineering the electrolyte formulation to form a stable, well-functioning solid electrolyte interphase (SEI) is a promising approach to improving these performance figures of merit. While design rules have been established for selecting electrolyte solvents and salt anions to establish a more robust SEI, the impact of altering cation identity is not well understood. In this work, we demonstrate that alkali metal additives (here, K<sup>+</sup>) alter SEI composition and thickness. Through post-mortem elemental analyses, we show that K<sup>+</sup> ions do not directly participate in metal electrodeposition, but rather modify the chemical and electrochemical reactivity of the electrode-electrolyte interface. Through a combination of quantitative nuclear magnetic resonance (NMR) spectroscopic characterization and density functional theory (DFT) simulations, we show that decomposition of electrolyte solvent molecules, ethylene carbonate (EC) and dimethyl carbonate (DMC), at the lithium metal surface is suppressed in the presence of a K<sup>+</sup> additive. We attribute this to K<sup>+</sup> being a softer cation compared to Li<sup>+</sup>, leading to preferred pair formation between K<sup>+</sup> and the soft base carbonates, and thus increased salt-solvent coordination. Electrolyte cation engineering is an underexplored strategy to control the SEI, and we believe that the mechanistic understanding and insight developed in this work will spur further investigation of this promising approach.</p>

Enhanced Ion Transport in an Ether Aided Super Concentrated Ionic Liquid Electrolyte for Long-Life Practical Lithium Metal Battery Applications

2020 ◽  
Author(s):  
Urbi Pal ◽  
Fangfang Chen ◽  
Derick Gyabang ◽  
Thushan Pathirana ◽  
Binayak Roy ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ion Transport ◽  
Current Density ◽  
Coulombic Efficiency ◽  
High Energy ◽  
Liquid Electrolyte ◽  
High Mass ◽  
Lithium Metal ◽  
Ionic Liquid Electrolyte ◽  
Lithium Metal Battery

We explore a novel ether aided superconcentrated ionic liquid electrolyte; a combination of ionic liquid, <i>N</i>-propyl-<i>N</i>-methylpyrrolidinium bis(fluorosulfonyl)imide (C<sub>3</sub>mpyrFSI) and ether solvent, <i>1,2</i> dimethoxy ethane (DME) with 3.2 mol/kg LiFSI salt, which offers an alternative ion-transport mechanism and improves the overall fluidity of the electrolyte. The molecular dynamics (MD) study reveals that the coordination environment of lithium in the ether aided ionic liquid system offers a coexistence of both the ether DME and FSI anion simultaneously and the absence of ‘free’, uncoordinated DME solvent. These structures lead to very fast kinetics and improved current density for lithium deposition-dissolution processes. Hence the electrolyte is used in a lithium metal battery against a high mass loading (~12 mg/cm<sup>2</sup>) LFP cathode which was cycled at a relatively high current rate of 1mA/cm<sup>2</sup> for 350 cycles without capacity fading and offered an overall coulombic efficiency of >99.8 %. Additionally, the rate performance demonstrated that this electrolyte is capable of passing current density as high as 7mA/cm<sup>2</sup> without any electrolytic decomposition and offers a superior capacity retention. We have also demonstrated an ‘anode free’ LFP-Cu cell which was cycled over 50 cycles and achieved an average coulombic efficiency of 98.74%. The coordination chemistry and (electro)chemical understanding as well as the excellent cycling stability collectively leads toward a breakthrough in realizing the practical applicability of this ether aided ionic liquid electrolytes in lithium metal battery applications, while delivering high energy density in a prototype cell.

scholarly journals Decoupling the origins of irreversible coulombic efficiency in anode-free lithium metal batteries

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chen-Jui Huang ◽  
Balamurugan Thirumalraj ◽  
Hsien-Chu Tao ◽  
Kassie Nigus Shitaw ◽  
Hogiartha Sutiono ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Rate Capability ◽  
Reversible Capacity ◽  
Data Interpretation ◽  
Lithium Metal ◽  
Safety Hazards ◽  
Practical Applications ◽  
Lithium Metal Batteries ◽  
Metallic Lithium ◽  
Other Information

AbstractAnode-free lithium metal batteries are the most promising candidate to outperform lithium metal batteries due to higher energy density and reduced safety hazards with the absence of metallic lithium anode during initial cell fabrication. In general, researchers report capacity retention, reversible capacity, or rate capability of the cells to study the electrochemical performance of anode-free lithium metal batteries. However, evaluating the behavior of batteries from limited aspects may easily overlook other information hidden deep inside the meretricious results or even lead to misguided data interpretation. In this work, we present an integrated protocol combining different types of cell configuration to determine various sources of irreversible coulombic efficiency in anode-free lithium metal cells. The decrypted information from the protocol provides an insightful understanding of the behaviors of LMBs and AFLMBs, which promotes their development for practical applications.

scholarly journals Stable Lithium-Carbon Composite Enabled by Dual-Salt Additives

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Lei Zheng ◽  
Feng Guo ◽  
Tuo Kang ◽  
Yingzhu Fan ◽  
Wei Gu ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Rate Capability ◽  
Negative Electrode ◽  
High Energy ◽  
Carbon Composite ◽  
High Reactivity ◽  
Cycling Stability ◽  
High Energy Density ◽  
Lithium Metal

AbstractLithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density. However, it suffers from poor cycling stability because of its high reactivity with liquid electrolytes. Therefore, continuous efforts have been put into improving the cycling Coulombic efficiency (CE) to extend the lifespan of the lithium metal negative electrode. Herein, we report that using dual-salt additives of LiPF6 and LiNO3 in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capability of a Li-carbon (Li-CNT) composite. As a result, an average cycling CE as high as 99.30% was obtained for the Li-CNT at a current density of 2.5 mA cm–2 and an negative electrode to positive electrode capacity (N/P) ratio of 2. The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether. The former component mainly originates from the decomposition of the LiNO3 additive, while the latter comes from the LiPF6-induced ring-opening polymerization of the ether solvent. This novel surface chemistry significantly improves the CE of Li negative electrode, revealing its importance for the practical application of lithium metal batteries.

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