scholarly journals Rapid Interfacial Exchange of Li Ions Dictates High Coulombic Efficiency in Li Metal Anodes

2021 ◽  
Author(s):  
Richard May ◽  
Keith Fritzsching ◽  
Dimitri Livitz ◽  
Steven R. Denny ◽  
Lauren Marbella
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Design Strategies ◽  
Battery Safety ◽  
Specific Energy Density ◽  
Low Solubility ◽  
New Framework ◽  
High Coulombic Efficiency

<p>Although Li metal batteries offer the highest possible specific energy density, practical application is plagued by Li filament growth with adverse effects on both Coulombic efficiency and battery safety. The structure and resulting properties of the solid electrolyte interphase (SEI) on Li metal is critical to controlling Li deposition morphologies and achieving high efficiency batteries. In this report, we use a combination of nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to show that fast Li transport and low solubility at the electrode/SEI interface in 0.5 M LiNO<sub>3</sub> + 0.5 M LiTFSI electrolyte bi-salt in 1,3-dioxolane:dimethoxyethane (DOL:DME, 1:1, v/v) are responsible for the formation of low surface area Li deposits and high Coulombic efficiency, despite the fact that the SEI is thicker and chemically more heterogeneous than LiTFSI alone. These data suggest that SEI design strategies that increase SEI stability and Li interfacial exchange rate will lead to more even current distribution, ultimately providing a new framework to generate smooth Li morphologies during plating/stripping.</p>

scholarly journals Rapid Interfacial Exchange of Li Ions Dictates High Coulombic Efficiency in Li Metal Anodes

2021 ◽  
Author(s):  
Richard May ◽  
Keith Fritzsching ◽  
Dimitri Livitz ◽  
Steven R. Denny ◽  
Lauren Marbella
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Design Strategies ◽  
Battery Safety ◽  
Specific Energy Density ◽  
Low Solubility ◽  
New Framework ◽  
High Coulombic Efficiency

<p>Although Li metal batteries offer the highest possible specific energy density, practical application is plagued by Li filament growth with adverse effects on both Coulombic efficiency and battery safety. The structure and resulting properties of the solid electrolyte interphase (SEI) on Li metal is critical to controlling Li deposition morphologies and achieving high efficiency batteries. In this report, we use a combination of nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to show that fast Li transport and low solubility at the electrode/SEI interface in 0.5 M LiNO<sub>3</sub> + 0.5 M LiTFSI electrolyte bi-salt in 1,3-dioxolane:dimethoxyethane (DOL:DME, 1:1, v/v) are responsible for the formation of low surface area Li deposits and high Coulombic efficiency, despite the fact that the SEI is thicker and chemically more heterogeneous than LiTFSI alone. These data suggest that SEI design strategies that increase SEI stability and Li interfacial exchange rate will lead to more even current distribution, ultimately providing a new framework to generate smooth Li morphologies during plating/stripping.</p>

scholarly journals An ultrathin ionomer interphase for high efficiency lithium anode in carbonate based electrolyte

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu-Ting Weng ◽  
Hao-Wen Liu ◽  
Allen Pei ◽  
FeiFei Shi ◽  
Hansen Wang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Current Collector ◽  
High Energy ◽  
Theoretical Simulation ◽  
Polyhedral Oligosilsesquioxane ◽  
Polyether Ether Ketone ◽  
Lithium Metal Anodes

AbstractHigh coulombic efficiency and dendrite suppression in carbonate electrolytes remain challenges to the development of high-energy lithium ion batteries containing lithium metal anodes. Here we demonstrate an ultrathin (≤100 nm) lithium-ion ionomer membrane consisting of lithium-exchanged sulfonated polyether ether ketone embedded with polyhedral oligosilsesquioxane as a coating layer on copper or lithium for achieving efficient and stable lithium plating-stripping cycles in a carbonate-based electrolyte. Operando analyses and theoretical simulation reveal the remarkable ability of the ionomer coating to enable electric field homogenization over a considerably large lithium-plating surface. The membrane coating, serving as an artificial solid-electrolyte interphase filter in minimizing parasitic reactions at the electrolyte-electrode interface, enables dendrite-free lithium plating on copper with outstanding coulombic efficiencies at room and elevated (50 °C) temperatures. The membrane coated copper demonstrates itself as a promising current collector for manufacturing high-quality pre-plated lithium thin-film anode.

Oxygen-defect-rich coating with nanoporous texture as both anode host and artificial SEI for dendrite-mitigated lithium-metal batteries

2020 ◽  
Author(s):  
Qingping Wu ◽  
Zhenguo Yao ◽  
Aochen Du ◽  
Han Wu ◽  
Minsong Huang ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Oxygen Defect ◽  
Lithium Metal ◽  
Long Period ◽  
Lithium Metal Batteries ◽  
High Coulombic Efficiency

The fragility of natural solid electrolyte interphase (SEI) and deformability of naked Li anode cannot meet the requirements on high coulombic efficiency (CE) and long-period cycling for Li metal batteries...

Extending the Low Temperature Operating Range of Sodium Metal Batteries with Acyclic/Cyclic Ether-Based Electrolytes

2021 ◽  
Author(s):  
Chuanlong Wang ◽  
Akila Thenuwara ◽  
Jianmin Luo ◽  
Pralav Shetty ◽  
Matthew McDowell ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Internal Resistance ◽  
Cyclic Ether ◽  
Binary Solvents ◽  
Cold Environments ◽  
Sodium Metal ◽  
Transmission Electron ◽  
Temperature Operating

Abstract Despite the promise of sodium electrochemistry at ambient temperature, the performance of sodium metal batteries in frigid environments is hindered by high internal resistance and unstable solid electrolyte interphase (SEI), which strongly depends on the electrolyte composition. Here we present an electrolyte formulation consisting of acyclic/cyclic ethers as binary solvents and a compatible sodium salt, which is thermally stable down to − 150°C. This electrolyte not only provides low resistance but enables a protective SEI in cold environments. Long-term sodium-metal cycling is demonstrated at the gelid temperature of − 80°C, showing small overpotentials of ~ 150 mV for over 750 hours. Both X-ray photoelectron spectroscopy and cryogenic transmission electron microscopy are performed to elucidate the temperature-dependent chemistry of the interphase. Full cells are further demonstrated, exhibiting a low decay rate (< 0.089% per cycle) and a high average Coulombic efficiency (> 99.5%) at temperatures as low as − 60°C.

Cellulose Separators with Integrated Carbon Nanotube Interlayers for Lithium-Sulfur Batteries: An Investigation into the Complex Interplay Between Cell Components

2019 ◽  
Author(s):  
Yu-Chuan Chien ◽  
Ruijun Pan ◽  
Ming-Tao Lee ◽  
Leif Nyholm ◽  
Daniel Brandell ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Holistic Approach ◽  
Cycle Life ◽  
Complex Interplay ◽  
Positive Electrodes ◽  
Lithium Sulfur Batteries ◽  
Cell Components ◽  
Redox Shuttle ◽  
Lithium Sulfur

This work aims to address two major roadblocks in the development of lithium-sulfur (Li-S) batteries: the inefficient deposition of Li on the metallic Li electrode and the parasitic "polysulfide redox shuttle". These roadblocks are here approached, respectively, by the combination of a cellulose separator with a cathode-facing conductive porous carbon interlayer, based on their previously reported individual benefits. The cellulose separator increases cycle life by 33%, and the interlayer by a further 25%, in test cells with positive electrodes with practically relevant specifications and a relatively low electrolyte/sulfur (E/S) ratio. Despite the prolonged cycle life, the combination of the interlayer and cellulose separator increases the polysulfide shuttle current, leading to reduced Coulombic efficiency. Based on XPS analyses, the latter is ascribed to a change in the composition of the solid electrolyte interphase (SEI) on Li. Meanwhile, electrolyte decomposition is found to be slower in cells with cellulose-based separators, which explains their longer cycle life. These counterintuitive observations demonstrate the complicated interactions between the cell components in the Li-S system and how strategies aiming to mitigate one unwanted process may exacerbate another. This study demonstrates the value of a holistic approach to the development of Li-S chemistry.<br>

scholarly journals Stable metal anodes enabled by a labile organic molecule bonded to a reduced graphene oxide aerogel

2020 ◽  
Vol 117 (48) ◽  
pp. 30135-30141
Author(s):  
Yue Gao ◽  
Daiwei Wang ◽  
Yun Kyung Shin ◽  
Zhifei Yan ◽  
Zhuo Han ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Efficiency ◽  
High Current Density ◽  
Solid Electrolyte Interphase ◽  
Metal Deposition ◽  
Reduced Graphene ◽  
Lithium Deposition ◽  
Reduced Graphene Oxide Aerogel ◽  
Graphene Oxide Aerogel

Metallic anodes (lithium, sodium, and zinc) are attractive for rechargeable battery technologies but are plagued by an unfavorable metal–electrolyte interface that leads to nonuniform metal deposition and an unstable solid–electrolyte interphase (SEI). Here we report the use of electrochemically labile molecules to regulate the electrochemical interface and guide even lithium deposition and a stable SEI. The molecule, benzenesulfonyl fluoride, was bonded to the surface of a reduced graphene oxide aerogel. During metal deposition, this labile molecule not only generates a metal-coordinating benzenesulfonate anion that guides homogeneous metal deposition but also contributes lithium fluoride to the SEI to improve Li surface passivation. Consequently, high-efficiency lithium deposition with a low nucleation overpotential was achieved at a high current density of 6.0 mA cm−2. A Li|LiCoO2cell had a capacity retention of 85.3% after 400 cycles, and the cell also tolerated low-temperature (−10 °C) operation without additional capacity fading. This strategy was applied to sodium and zinc anodes as well.

scholarly journals Quasi-graphitic carbon shell-induced Cu confinement promotes electrocatalytic CO2 reduction toward C2+ products

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ji-Yong Kim ◽  
Deokgi Hong ◽  
Jae-Chan Lee ◽  
Hyoung Gyun Kim ◽  
Sungwoo Lee ◽  
...  
Keyword(s):  
High Efficiency ◽  
Co2 Reduction ◽  
Value Added ◽  
Material Design ◽  
Catalyst System ◽  
Critical Issue ◽  
Reduction Reaction ◽  
Catalyst Design ◽  
Design Strategies ◽  
Faradaic Efficiency

AbstractFor steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO2 reduction reaction and provided a platform for rational material design. C2+ product selectivity could be additionally improved by doping p-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C2H4 at −0.55 V (vs RHE) and a C2H4 cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C2+ selectivity of 82.3% at a partial current density of 329.2 mA/cm2 was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO2-to-C2H4 conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion.

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