Stable cycling behavior of lithium metal anode by controlled 10 um deep surface reliefs

안진혁,조국영 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

To meet the demand for the high-energy-density rechargeable batteries, lithium (Li) metal anode, among various electrode materials, is often regarded as the “Holy grail” electrode because of its high theoretical capacity (3860 mA h g^-1) and the lowest electrochemical potential (-3.040 V vs. standard hydrogen electrode). Nevertheless, there are difficulty in using lithium metal as anode due to intrinsic problems such as unstable solid electrolyte interphase (SEI) and uncontrolled lithium dendrite growth. Various investigations have been conducted to solve these problems, however, there is a lack of fundamental insight into physical and chemical characteristics of Li anode. In this work, we fabricated two different shapes of 10 um deep surface reliefs (continuous and discontinuous type) on lithium metal anode for the understanding of physical characteristics of Li surface in cycling behavior of Li anode.

Effect of the dielectric constant of a liquid electrolyte on lithium metal anodes

Kim, Ju Young,Shin, Dong Ok,Chang, Taeyong,Kim, Kwang Man,Jeong, Jiseon,Park, Joonam,Lee, Yong Min,Cho, Kuk Young,Phatak, Charudatta,Hong, Seungbum,Lee, Young-Gi Elsevier 2019 ELECTROCHIMICA ACTA Vol.300 No.-

<P><B>Abstract</B></P> <P>Lithium metal is considered one of the most promising anode materials for realizing high volumetric and gravimetric energy density, owing to the high specific capacity (∼3860 mAh g<SUP>−1</SUP>) and the low electrochemical potential of lithium (−3.04 V vs. the standard hydrogen electrode). However, undesirable dendritic lithium growth and corresponding instability of the solid electrolyte interphase prevent safe and long-term use of lithium metal anodes. This paper presents a simple electrolyte approach to enhance the performance of lithium metal batteries by tuning the dielectric constant of the liquid electrolyte. Electrolyte formulations are designed by changing the concentration of ethylene carbonate to have various dielectric constants. This study confirms that high ethylene carbonate content in a liquid electrolyte enhances the cycling performance of lithium metal batteries because the electric field intensity applied to the electrolyte is reduced in relation to the polarization of the electrolyte and thus allows smooth lithium plating and formation of a stable solid electrolyte interphase. We believe that this approach provides an important concept for electrolyte system design suitable to lithium metal batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electric field intensity for lithium plating is derived from interface analysis. </LI> <LI> Electrolytes with different dielectric constants are designed systematically. </LI> <LI> Confirmed enhanced cycling performance of lithium occurs with high EC content. </LI> </UL> </P>

Effective Approaches to Preventing Dendrite Growth in Lithium Metal Anodes: A Review

( Jaeyun Ha ),( Jinhee Lee ),( Yong-tae Kim ),( Jinsub Choi ) 한국공업화학회 2023 공업화학 Vol.34 No.4

A lithium metal anode with high energy density has the potential to revolutionize the field of energy storage systems (ESS) and electric vehicles (EVs) that utilize rechargeable lithium-based batteries. However, the formation of lithium dendrites during cycling reduces the performance of the battery while posing a significant safety risk. In this review, we discuss various strategies for achieving dendrite-free lithium metal anodes, including electrode surface modification, the use of electrolyte additives, and the implementation of protective layers. We analyze the advantages and limitations of each strategy, and provide a critical evaluation of the current state of the art. We also highlight the challenges and opportunities for further research and development in this field. This review aims to provide a comprehensive overview of the different approaches to achieving dendrite-free lithium metal anodes, and to guide future research toward the development of safer and more efficient lithium metal anodes.

Suppression of dendrites and granules in surface-patterned Li metal anodes using CsPF₆

Kim, Seokwoo,Choi, Junyoung,Lee, Hongkyung,Jeong, Yong-Cheol,Lee, Yong Min,Ryou, Myung-Hyun Elsevier 2019 Journal of Power Sources Vol.413 No.-

<P><B>Abstract</B></P> <P>Unexpected Li deposition during plating, which causes low Coulombic efficiency and safety issues, limits the use of Li metal as an anode in commercial secondary batteries. With the recently developed micro-patterned Li metal anodes, dendrite formation during high current Li plating (2.4 mA cm<SUP>−2</SUP>) has successfully been reduced, as Li ions are guided into the patterned holes. However, the uncontrolled formation of granular Li is still observed in this material. To overcome these shortcomings, we have introduced cesium hexafluorophosphate into micro-patterned Li metal anodes. This additive employs the self-healing electrostatic shield mechanism to effectively reduce the formation of granular Li and Li dendrites, thereby significantly improving the electrochemical performance of the anodes even when only small amounts (0.05 M) of electrolyte are used. Our experiments revealed that batteries employing surface-patterned Li metal anodes with cesium hexafluorophosphate maintained 88.7% (96.6 mAh g<SUP>−1</SUP>) of their initial discharge capacity after the 900<SUP>th</SUP> cycle (Charging current density: C/2, 0.6 mA cm<SUP>−2</SUP>, Discharging current density: 1C, 1.2 mA cm<SUP>−2</SUP>), which is three times higher than the capacity observed with surface-patterned Li metal anodes without the additive (discharge capacity starts to decrease from 300 cycles).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cesium hexafluorophosphate was introduced to surface-patterned Li metal anodes. </LI> <LI> Cs<SUP>+</SUP> ions and patterned Li showed synergistic improvement in cycle performance. </LI> <LI> Cs<SUP>+</SUP> ions hindered the formation of granule and dendrites of patterned Li metal. </LI> <LI> Cs<SUP>+</SUP> ions stabilized the morphology of the surface-patterned Li metal anodes during cycling. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Formation and Inhibition of Metallic Lithium Microstructures in Lithium Batteries Driven by Chemical Crossover

Li, Wangda,Kim, Un-Hyuck,Dolocan, Andrei,Sun, Yang-Kook,Manthiram, Arumugam American Chemical Society 2017 ACS NANO Vol.11 No.6

<P>The formation of metallic lithium microstructures in the form of dendrites or mosses at the surface of anode electrodes (e.g., lithium metal, graphite, and silicon) leads to rapid capacity fade and poses grave safety risks in rechargeable lithium batteries. We present here a direct, relative quantitative analysis of lithium deposition on graphite anodes in pouch cells under normal operating conditions, paired with a model cathode material, the layered nickel-rich oxide LiNi0.61Co0.12Mn0.27O2, over the course of 3000 charge discharge cycles. Secondary-ion mass spectrometry chemically dissects the solid electrolyte interphase (SEI) on extensively cycled graphite with virtually atomic depth resolution and reveals substantial growth of Li-metal deposits. With the absence of apparent kinetic (e.g., fast charging) or stoichiometric restraints (e.g., overcharge) during cycling, we show lithium deposition on graphite is triggered by certain transition-metal ions (manganese in particular) dissolved from the cathode in a disrupted SEI. This insidious effect is found to initiate at a very early stage of cell operation (<200 cycles) and can be effectively inhibited by substituting a small amount of aluminum (similar to 1 mol %) in the cathode, resulting in much reduced transition-metal dissolution and drastically improved cyclability. Our results may also be applicable to studying the unstable electrodeposition of lithium on other substrates, including Li metal.</P>

Lithium fluoride layer formed by thermal evaporation for stable lithium metal anode in rechargeable batteries

Ko, Jaehwan,Yoon, Young Soo Elsevier 2019 THIN SOLID FILMS - Vol.673 No.-

<P><B>Abstract</B></P> <P>In this study, lithium fluoride (LiF) was deposited on lithium (Li) metal by thermal evaporation in order to reduce degradation of Li metal batteries caused by growth of Li dendrites. Li | Li symmetric cells were used to measure impedance changes, overvoltage after cycling at 1 mA/cm<SUP>2</SUP> and 1 mAh/cm<SUP>2</SUP>, and surface images after 100 cycles. In addition, the residual capacity and Coulombic efficiency after 0.5C charge/discharge cycling were confirmed using LiCoO<SUB>2</SUB>|Li cells. Based on electrochemical impedance spectroscopy measurements, Li | Li symmetric cells made of LiF-coated Li showed no impedance changes, even 12 h after fabrication. During the overvoltage test with Li | Li symmetric cells, the cell with a 300 nm thick LiF layer showed highest stability under repeated cycling. The surface of the 300 nm LiF-coated Li was relatively smooth and almost no abnormal growth of Li was observed. In the LiCoO<SUB>2</SUB>|Li cells, 200 nm and 300 nm LiF-coated cells showed the best performance in terms of residual capacity. The 300 nm LiF-coated Li cell exhibited close to 100% Coulombic efficiency and remained more stable than the bare Li cell.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lithium fluoride was deposited by thermal evaporation for stable lithium anode. </LI> <LI> The symmetric cell with 300 nm thick lithium fluoride was the most stable. </LI> <LI> Lithium fluoride-coated surface was relatively smooth after cycling. </LI> <LI> The LiCoO<SUB>2</SUB> cell with 300 nm thick lithium fluoride showed the best performance. </LI> </UL> </P>

Electrochemical properties of a lithium-impregnated metal foam anode for thermal batteries

Choi, Yu-Song,Yu, Hye-Ryeon,Cheong, Hae-Won Elsevier 2015 Journal of Power Sources Vol.276 No.-

<P><B>Abstract</B></P> <P>Lithium-impregnated metal foam anodes (LIMFAs) are fabricated and investigated. The LIMFAs are prepared by the impregnation of lithium into molten-salt-coated nickel metal foam. A single cell with the LIMFA exhibits a specific capacity of 3009 As g<SUP>−1</SUP>. For comparison, a single cell with a LiSi alloy anode is also discharged, demonstrating a specific capacity of 1050 As g<SUP>−1</SUP>. These significant improvements can be attributed to the large amount of lithium impregnated into the metal foam as well as the molten lithium holding capability of the foam. Due to their excellent electrochemical properties, LIMFAs are suitable for use in thermal batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We investigated an alternative to the conventional Li–Si anode for thermal batteries. </LI> <LI> The LIMFAs are prepared by the impregnation of lithium into salt-coated metal foam. </LI> <LI> The LIMFA has a higher specific capacity than the conventional Li–Si alloy anode. </LI> </UL> </P>

Effect of an organic additive in the electrolyte on suppressing the growth of Li dendrites in Li metal-based batteries

Ho, Van-Chuong,Ngo, Duc Tung,Le, Hang T.T.,Verma, Rakesh,Kim, Hee-Sang,Park, Choong-Nyeon,Park, Chan-Jin Elsevier 2018 ELECTROCHIMICA ACTA Vol.279 No.-

<P><B>Abstract</B></P> <P>Lithium metal has attracted much attention as an anode material for high-performance batteries owing to its high specific capacity and electrode potential. However, the Li metal electrode could suffer from the dendritic growth of Li during the cell operation due to the high reactivity of Li with organic electrolytes. To address this issue, we propose the use of thiourea as an electrolyte additive for Li metal-based batteries. The thiourea additive in LiTFSI/TEGDME electrolyte allowed the formation of a stable and uniform solid electrolyte interface layer on the Li electrode, thereby aiding the suppression of dendritic growth of Li and further electrolyte decomposition. Accordingly, a Li symmetric cell containing the thiourea additive exhibited six-times longer cycle life than a cell without the additive. Further, the electrolyte additive was also successfully employed in a Li-O<SUB>2</SUB> cell to improve its cyclability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thiourea is explored as an electrolyte additive for lithium metal-based batteries for the first time. </LI> <LI> Growth of lithium dendrites is controlled by varying the concentration of thiourea additive in the electrolyte. </LI> <LI> Thiourea additive, decomposition of the liquid electrolyte involving LiTFSI salt is suppressed during the discharge-charge. </LI> <LI> The Li-O<SUB>2</SUB> battery employing the liquid electrolyte containing the thiourea additive exhibits good cyclability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Designing of 3D porous silicon/carbon complex anode based on metal‑organic frameworks for lithium‑ion battery

Won Jun Ahn,Byeong Hyeon Park,Sang Wan Seo,Seok Kim,Ji Sun Im 한국탄소학회 2023 Carbon Letters Vol.33 No.7

The complexation of silicon with carbon materials is considered an effective method for using silicon as an anode material for lithium-ion batteries. In the present study, carbon frameworks with a 3D porous structure were fabricated using metal–organic frameworks (MOFs), which have been drawing significant attention as a promising material in a wide range of applications. Subsequently, the fabricated carbon frameworks were subjected to CVD to obtain silicon-carbon complexes. These siliconcarbon complexes with a 3D porous structure exhibited excellent rate capability because they provided sufficient paths for Li-ion diffusion while facilitating contact with the electrolyte. In addition, unoccupied space within the silicon complex, combined with the stable structure of the carbon framework, allowed the volume expansion of silicon and the resultant stress to be more effectively accommodated, thereby reducing electrode expansion. The major findings of the present study demonstrate the applicability of MOF-based carbon frameworks as a material for silicon complex anodes.

Technical issues and recent progress in metal-air batteries

이종원,정규남 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

In recent years, there has been a strong demand for advanced rechargeable battery systems with high energy storage capability. Among the various energy storage technologies under development, a metal-air battery, in which a metal anode (Li, Zn, etc.) is coupled with an air-breathing porous cathode, delivers much higher specific energy compared to conventional battery chemistries such as lithium-ion batteries. During discharge, the metal-air battery generates electricity through an oxidation reaction of a metal anode and a reduction reaction of oxygen (O2) on a porous cathode. The reverse reactions occur upon charge. This talk introduces the technical challenges facing development of metal-air batteries with specific attention to electrochemistry and materials, and then presents promising strategies to designing electrodes and electrolytes that could improve a battery`s capacity, energy efficiency, rate-capability, and cyclability.