scholarly journals Fluorine-donating electrolytes enable highly reversible 5-V-class Li metal batteries

2018 ◽  
Vol 115 (6) ◽  
pp. 1156-1161 ◽  
Author(s):  
Liumin Suo ◽  
Weijiang Xue ◽  
Mallory Gobet ◽  
Steve G. Greenbaum ◽  
Chao Wang ◽  
...  

Lithium metal has gravimetric capacity ∼10× that of graphite which incentivizes rechargeable Li metal batteries (RLMB) development. A key factor that limits practical use of RLMB is morphological instability of Li metal anode upon electrodeposition, reflected by the uncontrolled area growth of solid–electrolyte interphase that traps cyclable Li, quantified by the Coulombic inefficiency (CI). Here we show that CI decreases approximately exponentially with increasing donatable fluorine concentration of the electrolyte. By using up to 7 m of Li bis(fluorosulfonyl)imide in fluoroethylene carbonate, where both the solvent and the salt donate F, we can significantly suppress anode porosity and improve the Coulombic efficiency to 99.64%. The electrolyte demonstrates excellent compatibility with 5-V LiNi0.5Mn1.5O4 cathode and Al current collector beyond 5 V. As a result, an RLMB full cell with only 1.4× excess lithium as the anode was demonstrated to cycle above 130 times, at industrially significant loading of 1.83 mAh/cm2 and 0.36 C. This is attributed to the formation of a protective LiF nanolayer, which has a wide bandgap, high surface energy, and small Burgers vector, making it ductile at room temperature and less likely to rupture in electrodeposition.

2020 ◽  
Vol 10 (12) ◽  
pp. 4185 ◽  
Author(s):  
Rajesh Pathak ◽  
Yue Zhou ◽  
Qiquan Qiao

Rechargeable lithium metal anode (LMA) based batteries have attracted great attention as next-generation high-energy-density storage systems to fuel the extensive practical applications in portable electronics and electric vehicles. However, the formation of unstable solid-electrolyte- interphase (SEI) and growth of lithium dendrite during plating/stripping cycles stimulate safety concern, poor coulombic efficiency (CE), and short lifespan of the lithium metal batteries (LMBs). To address these issues, the rational design of micro/nanostructured Li hosts are widely adopted in LMBs. The high surface area of the interconnected conductive framework can homogenize the Li-ion flux distribution, lower the effective current density, and provides sufficient space for Li accommodation. However, the poor lithiophilicity of the micro/nanostructure host cannot govern the initial lithium nucleation, which leads to the non-uniform/dendritic Li deposition and unstable SEI formation. As a result, the nucleation overpotential and voltage hysteresis increases, which eventually leads to poor battery cycling performance. Thus, it is imperative to decorate a micro/nanostructured Li host with lithiophilic coatings or seeds for serving as a homogeneous nucleation site to guide the uniform lithium deposition. In this review, we summarize research progress on porous metal and non-metal based lithiophilic micro/nanostructured Li hosts. We present the synthesis, structural properties, and the significance of lithiophilic decorated micro/nanostructured Li host in the LMBs. Finally, the perspectives and critical challenges needed to address for the further improvement of LMBs are concluded.


Author(s):  
Yu Wu ◽  
Qintao Sun ◽  
Yue Liu ◽  
Peiping Yu ◽  
Bingyun Ma ◽  
...  

Abstract Metallic lithium is considered a promising anode that can significantly increase the energy density of rechargeable lithium-based batteries, but problems like uncontrollable growth of lithium dendrites and formation of dead lithium impede its application. Recently, a low-concentration single-salt two-solvent electrolyte, 1M LiTFSI/FDMA/FEC, has attracted attention because a high coulombic efficiency can be achieved even after many cycles owing to the formation of a robust solid electrolyte interface (SEI). However, the reaction mechanism and SEI structure remain unclear, posing significant challenges for further improvement. Here, a hybrid ab initio and reactive force field (HAIR) method revealed the underlying reaction mechanisms and detailed formation pathway. 1 ns HAIR simulation provides critical information on the initial reduction mechanism of solvent (FDMA and FEC) and salt (LiTFSI). FDMA and FEC quickly decompose to provide F- that builds LiF as the major component of the inner layer of inorganic SEI, which has been demonstrated to protect Li anode. Decomposition of FDMA also leads to a significant nitrogen-containing composition, producing Li-N-C, LixN, and other organic components that increase the conductivity of SEI to increase performance. XPS analysis confirms evolution of SEI morphology consistent with available experiments. These results provide atomic insight into SEI formation, which should be beneficial for the rational design of advanced electrolytes


2021 ◽  
Vol 11 (24) ◽  
pp. 12027
Author(s):  
Yeyoung Ha ◽  
Maxwell C. Schulze ◽  
Sarah Frisco ◽  
Stephen E. Trask ◽  
Glenn Teeter ◽  
...  

Low first-cycle Coulombic efficiency is especially poor for silicon (Si)-based anodes due to the high surface area of the Si-active material and extensive electrolyte decomposition during the initial cycles forming the solid electrolyte interphase (SEI). Therefore, developing successful prelithiation methods will greatly benefit the development of lithium-ion batteries (LiBs) utilizing Si anodes. In pursuit of this goal, in this study, lithium oxide (Li2O) was added to a LiNi0.6Mn0.2Co0.2O2 (NMC622) cathode using a scalable ball-milling approach to compensate for the initial Li loss at the anode. Different milling conditions were tested to evaluate the impact of particle morphology on the additive performance. In addition, Co3O4, a well-known oxygen evolution reaction catalyst, was introduced to facilitate the activation of Li2O. The Li2O + Co3O4 additives successfully delivered an additional capacity of 1116 mAh/gLi2O when charged up to 4.3 V in half cells and 1035 mAh/gLi2O when charged up to 4.1 V in full cells using Si anodes.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu-Ting Weng ◽  
Hao-Wen Liu ◽  
Allen Pei ◽  
FeiFei Shi ◽  
Hansen Wang ◽  
...  

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.


2019 ◽  
Vol 2 (4) ◽  
pp. 509-517 ◽  
Author(s):  
Hansen Wang ◽  
Yayuan Liu ◽  
Yuzhang Li ◽  
Yi Cui

Abstract Li metal is the ultimate anode choice due to its highest theoretical capacity and lowest electrode potential, but it is far from practical applications with its poor cycle lifetime. Recent research progresses show that materials designs of interphase and host structures for Li metal are two effective ways addressing the key issues of Li metal anodes. Despite the exciting improvement on Li metal cycling capability, problems still exist with these methodologies, such as the deficient long-time cycling stability of interphase materials and the accelerated Li corrosion for high surface area three-dimensional composite Li anodes. As a result, Coulombic efficiency of Li metal is still not sufficient for full-cell cycling. In the near future, an interphase protected three-dimensional composite Li metal anode, combined with high performance novel electrolytes might be the ultimate solution. Besides, nanoscale characterization technologies are also vital for guiding future Li metal anode designs. Graphic Abstract


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jaewoo Lee ◽  
Min-Sik Park ◽  
Jung Ho Kim

AbstractThe development of lithium (Li)-metal anode is high priority research to initiate next-generation Li batteries. Applying Li-metal in practical applications as anode still has many hurdles to clear away, such as low Coulombic efficiency and capacity degradation by the continuous formation of dead Li. We demonstrate that cobalt (Co) nanoparticle incorporation in a porous carbon host anode can play a critical role in the formation of a thick lithium fluoride dominated solid-electrolyte interphase in ether-based electrolyte. As a result, the host anode containing Co nanoparticles shows excellent electrochemical performance with high Li-metal reversible capacity and even stable long-term cyclability with no dead Li formation.


2017 ◽  
Vol 114 (14) ◽  
pp. 3584-3589 ◽  
Author(s):  
Ying Zhang ◽  
Wei Luo ◽  
Chengwei Wang ◽  
Yiju Li ◽  
Chaoji Chen ◽  
...  

Lithium metal anode with the highest capacity and lowest anode potential is extremely attractive to battery technologies, but infinite volume change during the Li stripping/plating process results in cracks and fractures of the solid electrolyte interphase, low Coulombic efficiency, and dendritic growth of Li. Here, we use a carbonized wood (C-wood) as a 3D, highly porous (73% porosity) conductive framework with well-aligned channels as Li host material. We discovered that molten Li metal can infuse into the straight channels of C-wood to form a Li/C-wood electrode after surface treatment. The C-wood channels function as excellent guides in which the Li stripping/plating process can take place and effectively confine the volume change that occurs. Moreover, the local current density can be minimized due to the 3D C-wood framework. Therefore, in symmetric cells, the as-prepared Li/C-wood electrode presents a lower overpotential (90 mV at 3 mA⋅cm−2), more-stable stripping/plating profiles, and better cycling performance (∼150 h at 3 mA⋅cm−2) compared with bare Li metal electrode. Our findings may open up a solution for fabricating stable Li metal anode, which further facilitates future application of high-energy-density Li metal batteries.


Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Zhijia Huang ◽  
Debin Kong ◽  
Yunbo Zhang ◽  
Yaqian Deng ◽  
Guangmin Zhou ◽  
...  

Lithium (Li) metal has been regarded as one of the most promising anode materials to meet the urgent requirements for the next-generation high-energy density batteries. However, the practical use of lithium metal anode is hindered by the uncontrolled growth of Li dendrites, resulting in poor cycling stability and severe safety issues. Herein, vertical graphene (VG) film grown on graphite paper (GP) as an all-carbon current collector was utilized to regulate the uniform Li nucleation and suppress the growth of dendrites. The high surface area VG grown on GP not only reduces the local current density to the uniform electric field but also allows fast ion transport to homogenize the ion gradients, thus regulating the Li deposition to suppress the dendrite growth. The Li deposition can be further guided with the lithiation reaction between graphite paper and Li metal, which helps to increase lithiophilicity and reduce the Li nucleation barrier as well as the overpotential. As a result, the VG film-based anode demonstrates a stable cycling performance at a current density higher than 5 mA cm-2 in half cells and a small hysteresis of 50 mV at 1 mA cm-2 in symmetric cells. This work provides an efficient strategy for the rational design of highly stable Li metal anodes.


2019 ◽  
Author(s):  
Yu-Chuan Chien ◽  
Ruijun Pan ◽  
Ming-Tao Lee ◽  
Leif Nyholm ◽  
Daniel Brandell ◽  
...  

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>


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