Sang Cheol Kim

All Publications

• In Situ Prelithiation by Direct Integration of Lithium Mesh into Battery Cells. Nano letters Yang, Y., Wang, J., Kim, S. C., Zhang, W., Peng, Y., Zhang, P., Vila, R. A., Ma, Y., Jeong, Y. K., Cui, Y. 2023

  Abstract

  Silicon (Si)-based anodes are promising for next-generation lithium (Li)-ion batteries due to their high theoretical capacity (3600 mAh/g). However, they suffer quantities of capacity loss in the first cycle from initial solid electrolyte interphase (SEI) formation. Here, we present an in situ prelithiation method to directly integrate a Li metal mesh into the cell assembly. A series of Li meshes are designed as prelithiation reagents, which are applied to the Si anode in battery fabrication and spontaneously prelithiate Si with electrolyte addition. Various porosities of Li meshes tune prelithiation amounts to control the degree of prelithiation precisely. Besides, the patterned mesh design enhances the uniformity of prelithiation. With an optimized prelithiation amount, the in situ prelithiated Si-based full cell shows a constant >30% capacity improvement in 150 cycles. This work presents a facile prelithiation approach to improve battery performance.

  View details for DOI 10.1021/acs.nanolett.3c00859

  View details for PubMedID 37236151

• Dissolution of the Solid Electrolyte Interphase and Its Effects on Lithium Metal Anode Cyclability. Journal of the American Chemical Society Sayavong, P., Zhang, W., Oyakhire, S. T., Boyle, D. T., Chen, Y., Kim, S. C., Vilá, R. A., Holmes, S. E., Kim, M. S., Bent, S. F., Bao, Z., Cui, Y. 2023

  Abstract

  At >95% Coulombic efficiencies, most of the capacity loss for Li metal anodes (LMAs) is through the formation and growth of the solid electrolyte interphase (SEI). However, the mechanism through which this happens remains unclear. One property of the SEI that directly affects its formation and growth is the SEI's solubility in the electrolyte. Here, we systematically quantify and compare the solubility of SEIs derived from ether-based electrolytes optimized for LMAs using in-operando electrochemical quartz crystal microbalance (EQCM). A correlation among solubility, passivity, and cyclability established in this work reveals that SEI dissolution is a major contributor to the differences in passivity and electrochemical performance among battery electrolytes. Together with our EQCM, X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR) spectroscopy results, we show that solubility depends on not only the SEI's composition but also the properties of the electrolyte. This provides a crucial piece of information that could help minimize capacity loss due to SEI formation and growth during battery cycling and aging.

  View details for DOI 10.1021/jacs.3c03195

  View details for PubMedID 37220230

• Data-driven electrolyte design for lithium metal anodes. Proceedings of the National Academy of Sciences of the United States of America Kim, S. C., Oyakhire, S. T., Athanitis, C., Wang, J., Zhang, Z., Zhang, W., Boyle, D. T., Kim, M. S., Yu, Z., Gao, X., Sogade, T., Wu, E., Qin, J., Bao, Z., Bent, S. F., Cui, Y. 2023; 120 (10): e2214357120

  Abstract

  Improving Coulombic efficiency (CE) is key to the adoption of high energy density lithium metal batteries. Liquid electrolyte engineering has emerged as a promising strategy for improving the CE of lithium metal batteries, but its complexity renders the performance prediction and design of electrolytes challenging. Here, we develop machine learning (ML) models that assist and accelerate the design of high-performance electrolytes. Using the elemental composition of electrolytes as the features of our models, we apply linear regression, random forest, and bagging models to identify the critical features for predicting CE. Our models reveal that a reduction in the solvent oxygen content is critical for superior CE. We use the ML models to design electrolyte formulations with fluorine-free solvents that achieve a high CE of 99.70%. This work highlights the promise of data-driven approaches that can accelerate the design of high-performance electrolytes for lithium metal batteries.

  View details for DOI 10.1073/pnas.2214357120

  View details for PubMedID 36848560

• Revealing the Multifunctions of Li3N in the Suspension Electrolyte for Lithium Metal Batteries. ACS nano Kim, M. S., Zhang, Z., Wang, J., Oyakhire, S. T., Kim, S. C., Yu, Z., Chen, Y., Boyle, D. T., Ye, Y., Huang, Z., Zhang, W., Xu, R., Sayavong, P., Bent, S. F., Qin, J., Bao, Z., Cui, Y. 2023

  Abstract

  Inorganic-rich solid-electrolyte interphases (SEIs) on Li metal anodes improve the electrochemical performance of Li metal batteries (LMBs). Therefore, a fundamental understanding of the roles played by essential inorganic compounds in SEIs is critical to realizing and developing high-performance LMBs. Among the prevalent SEI inorganic compounds observed for Li metal anodes, Li3N is often found in the SEIs of high-performance LMBs. Herein, we elucidate new features of Li3N by utilizing a suspension electrolyte design that contributes to the improved electrochemical performance of the Li metal anode. Through empirical and computational studies, we show that Li3N guides Li electrodeposition along its surface, creates a weakly solvating environment by decreasing Li+-solvent coordination, induces organic-poor SEI on the Li metal anode, and facilitates Li+ transport in the electrolyte. Importantly, recognizing specific roles of SEI inorganics for Li metal anodes can serve as one of the rational guidelines to design and optimize SEIs through electrolyte engineering for LMBs.

  View details for DOI 10.1021/acsnano.2c12470

  View details for PubMedID 36700841

• Correlating the Formation Protocols of Solid Electrolyte Interphases with Practical Performance Metrics in Lithium Metal Batteries ACS ENERGY LETTERS Oyakhire, S. T., Zhang, W., Yu, Z., Holmes, S. E., Sayavong, P., Kim, S., Boyle, D. T., Kim, M., Zhang, Z., Cui, Y., Bent, S. F. 2023: 869-877

  View details for DOI 10.1021/acsenergylett.2c02137

  View details for Web of Science ID 000913929700001

• Correlating Kinetics to Cyclability Reveals Thermodynamic Origin of Lithium Anode Morphology in Liquid Electrolytes. Journal of the American Chemical Society Boyle, D. T., Kim, S. C., Oyakhire, S. T., Vila, R. A., Huang, Z., Sayavong, P., Qin, J., Bao, Z., Cui, Y. 2022

  Abstract

  The rechargeability of lithium metal batteries strongly depends on the electrolyte. The uniformity of the electroplated Li anode morphology underlies this dependence, so understanding the main drivers of uniform plating is critical for further electrolyte discovery. Here, we correlate electroplating kinetics with cyclability across several classes of electrolytes to reveal the mechanistic influence electrolytes have on morphology. Fast charge-transfer kinetics at fresh Li-electrolyte interfaces correlate well with uniform morphology and cyclability, whereas the resistance of Li+ transport through the solid electrolyte interphase (SEI) weakly correlates with cyclability. These trends contrast with the conventional thought that Li+ transport through the electrolyte or SEI is the main driver of morphological differences between classes of electrolytes. Relating these trends to Li+ solvation, Li nucleation, and the charge-transfer mechanism instead suggests that the Li/Li+ equilibrium potential and the surface energy─thermodynamic factors modulated by the strength of Li+ solvation─underlie electrolyte-dependent trends of Li morphology. Overall, this work provides an insight for discovering functional electrolytes, tuning kinetics in batteries, and explaining why weakly solvating fluorinated electrolytes favor uniform Li plating.

  View details for DOI 10.1021/jacs.2c08182

  View details for PubMedID 36318744

• An Interdigitated Li-Solid Polymer Electrolyte Framework for Interfacial Stable All-Solid-State Batteries ADVANCED ENERGY MATERIALS Yang, Y., Chen, H., Wan, J., Xu, R., Zhang, P., Zhang, W., Oyakhire, S. T., Kim, S., Boyle, D. T., Peng, Y., Ma, Y., Cui, Y. 2022

  View details for DOI 10.1002/aenm.202201160

  View details for Web of Science ID 000843752000001

• Liquid electrolyte: The nexus of practical lithium metal batteries JOULE Wang, H., Yu, Z., Kong, X., Kim, S., Boyle, D. T., Qin, J., Bao, Z., Cui, Y. 2022; 6 (3): 588-616

  View details for DOI 10.1016/j.joule.2021.12.018

  View details for Web of Science ID 000773205200008

• Graphene coating on silicon anodes enabled by thermal surface modification for high-energy lithium-ion batteries MRS BULLETIN Kim, S., Huang, W., Zhang, Z., Wang, J., Kim, Y., Jeong, Y., Oyakhire, S. T., Yang, Y., Cui, Y. 2022

  View details for DOI 10.1557/s43577-021-00191-4

  View details for Web of Science ID 000771066700003

• Suspension electrolyte with modified Li+ solvation environment for lithium metal batteries. Nature materials Kim, M. S., Zhang, Z., Rudnicki, P. E., Yu, Z., Wang, J., Wang, H., Oyakhire, S. T., Chen, Y., Kim, S. C., Zhang, W., Boyle, D. T., Kong, X., Xu, R., Huang, Z., Huang, W., Bent, S. F., Wang, L., Qin, J., Bao, Z., Cui, Y. 1800

  Abstract

  Designing a stable solid-electrolyte interphase on a Li anode is imperative to developing reliable Li metal batteries. Herein, we report a suspension electrolyte design that modifies the Li+ solvation environment in liquid electrolytes and creates inorganic-rich solid-electrolyte interphases on Li. Li2O nanoparticles suspended in liquid electrolytes were investigated as a proof of concept. Through theoretical and empirical analyses of Li2O suspension electrolytes, the roles played by Li2O in the liquid electrolyte and solid-electrolyte interphases of the Li anode are elucidated. Also, the suspension electrolyte design is applied in conventional and state-of-the-art high-performance electrolytes to demonstrate its applicability. Based on electrochemical analyses, improved Coulombic efficiency (up to ~99.7%), reduced Li nucleation overpotential, stabilized Li interphases and prolonged cycle life of anode-free cells (~70 cycles at 80% of initial capacity) were achieved with the suspension electrolytes. We expect this design principle and our findings to be expanded into developing electrolytes and solid-electrolyte interphases for Li metal batteries.

  View details for DOI 10.1038/s41563-021-01172-3

  View details for PubMedID 35039645

• Rational solvent molecule tuning for high-performance lithium metal battery electrolytes NATURE ENERGY Yu, Z., Rudnicki, P. E., Zhang, Z., Huang, Z., Celik, H., Oyakhire, S. T., Chen, Y., Kong, X., Kim, S., Xiao, X., Wang, H., Zheng, Y., Kamat, G. A., Kim, M., Bent, S. F., Qin, J., Cui, Y., Bao, Z. 2022

  View details for DOI 10.1038/s41560-021-00962-y

  View details for Web of Science ID 000742253900001

• Steric Effect Tuned Ion Solvation Enabling Stable Cycling of High-Voltage Lithium Metal Battery. Journal of the American Chemical Society Chen, Y., Yu, Z., Rudnicki, P., Gong, H., Huang, Z., Kim, S. C., Lai, J., Kong, X., Qin, J., Cui, Y., Bao, Z. 2021

  Abstract

  1,2-Dimethoxyethane (DME) is a common electrolyte solvent for lithium metal batteries. Various DME-based electrolyte designs have improved long-term cyclability of high-voltage full cells. However, insufficient Coulombic efficiency at the Li anode and poor high-voltage stability remain a challenge for DME electrolytes. Here, we report a molecular design principle that utilizes a steric hindrance effect to tune the solvation structures of Li+ ions. We hypothesized that by substituting the methoxy groups on DME with larger-sized ethoxy groups, the resulting 1,2-diethoxyethane (DEE) should have a weaker solvation ability and consequently more anion-rich inner solvation shells, both of which enhance interfacial stability at the cathode and anode. Experimental and computational evidence indicates such steric-effect-based design leads to an appreciable improvement in electrochemical stability of lithium bis(fluorosulfonyl)imide (LiFSI)/DEE electrolytes. Under stringent full-cell conditions of 4.8 mAh cm-2 NMC811, 50 mum thin Li, and high cutoff voltage at 4.4 V, 4 M LiFSI/DEE enabled 182 cycles until 80% capacity retention while 4 M LiFSI/DME only achieved 94 cycles. This work points out a promising path toward the molecular design of non-fluorinated ether-based electrolyte solvents for practical high-voltage Li metal batteries.

  View details for DOI 10.1021/jacs.1c09006

  View details for PubMedID 34709034

• Potentiometric Measurement to Probe Solvation Energy and Its Correlation to Lithium Battery Cyclability. Journal of the American Chemical Society Kim, S. C., Kong, X., Vila, R. A., Huang, W., Chen, Y., Boyle, D. T., Yu, Z., Wang, H., Bao, Z., Qin, J., Cui, Y. 2021

  Abstract

  The electrolyte plays a critical role in lithium-ion batteries, as it impacts almost every facet of a battery's performance. However, our understanding of the electrolyte, especially solvation of Li+, lags behind its significance. In this work, we introduce a potentiometric technique to probe the relative solvation energy of Li+ in battery electrolytes. By measuring open circuit potential in a cell with symmetric electrodes and asymmetric electrolytes, we quantitatively characterize the effects of concentration, anions, and solvents on solvation energy across varied electrolytes. Using the technique, we establish a correlation between cell potential (Ecell) and cyclability of high-performance electrolytes for lithium metal anodes, where we find that solvents with more negative cell potentials and positive solvation energies-those weakly binding to Li+-lead to improved cycling stability. Cryogenic electron microscopy reveals that weaker solvation leads to an anion-derived solid-electrolyte interphase that stabilizes cycling. Using the potentiometric measurement for characterizing electrolytes, we establish a correlation that can guide the engineering of effective electrolytes for the lithium metal anode.

  View details for DOI 10.1021/jacs.1c03868

  View details for PubMedID 34184873

• Correlating Li-Ion Solvation Structures and Electrode Potential Temperature Coefficients. Journal of the American Chemical Society Wang, H. n., Kim, S. C., Rojas, T. n., Zhu, Y. n., Li, Y. n., Ma, L. n., Xu, K. n., Ngo, A. T., Cui, Y. n. 2021

  Abstract

  Temperature coefficients (TCs) for either electrochemical cell voltages or potentials of individual electrodes have been widely utilized to study the thermal safety and cathode/anode phase changes of lithium (Li)-ion batteries. However, the fundamental significance of single electrode potential TCs is little known. In this work, we discover that the Li-ion desolvation process during Li deposition/intercalation is accompanied by considerable entropy change, which significantly contributes to the measured Li/Li+ electrode potential TCs. To explore this phenomenon, we compare the Li/Li+ electrode potential TCs in a series of electrolyte formulations, where the interaction between Li-ion and solvent molecules occurs at varying strength as a function of both solvent and anion species as well as salt concentrations. As a result, we establish correlations between electrode potential TCs and Li-ion solvation structures and further verify them by ab initio molecular dynamics simulations. We show that measurements of Li/Li+ electrode potential TCs provide valuable knowledge regarding the Li-ion solvation environments and could serve as a screening tool when designing future electrolytes for Li-ion/Li metal batteries.

  View details for DOI 10.1021/jacs.0c10587

  View details for PubMedID 33506677

• Air-Filtering Masks for Respiratory Protection from PM2.5 and Pandemic Pathogens. One earth (Cambridge, Mass.) Xu, J., Xiao, X., Zhang, W., Xu, R., Kim, S. C., Cui, Y., Howard, T. T., Wu, E., Cui, Y. 2020; 3 (5): 574–89

  Abstract

  Air-filtering masks, also known as respirators, protect wearers from inhaling fine particulate matter (PM2.5) in polluted air, as well as airborne pathogens during a pandemic, such as the ongoing COVID-19 pandemic. Fibrous medium, used as the filtration layer, is the most essential component of an air-filtering mask. This article presents an overview of the development of fibrous media for air filtration. We first synthesize the literature on several key factors that affect the filtration performance of fibrous media. We then concentrate on two major techniques for fabricating fibrous media, namely, meltblown and electrospinning. In addition, we underscore the importance of electret filters by reviewing various methods for imparting electrostatic charge on fibrous media. Finally, this article concludes with a perspective on the emerging research opportunities amid the COVID-19 crisis.

  View details for DOI 10.1016/j.oneear.2020.10.014

  View details for PubMedID 33748744

• Underpotential lithium plating on graphite anodes caused by temperature heterogeneity. Proceedings of the National Academy of Sciences of the United States of America Wang, H., Zhu, Y., Kim, S. C., Pei, A., Li, Y., Boyle, D. T., Wang, H., Zhang, Z., Ye, Y., Huang, W., Liu, Y., Xu, J., Li, J., Liu, F., Cui, Y. 2020

  Abstract

  Rechargeability and operational safety of commercial lithium (Li)-ion batteries demand further improvement. Plating of metallic Li on graphite anodes is a critical reason for Li-ion battery capacity decay and short circuit. It is generally believed that Li plating is caused by the slow kinetics of graphite intercalation, but in this paper, we demonstrate that thermodynamics also serves a crucial role. We show that a nonuniform temperature distribution within the battery can make local plating of Li above 0 V vs. Li0/Li+ (room temperature) thermodynamically favorable. This phenomenon is caused by temperature-dependent shifts of the equilibrium potential of Li0/Li+ Supported by simulation results, we confirm the likelihood of this failure mechanism during commercial Li-ion battery operation, including both slow and fast charging conditions. This work furthers the understanding of nonuniform Li plating and will inspire future studies to prolong the cycling lifetime of Li-ion batteries.

  View details for DOI 10.1073/pnas.2009221117

  View details for PubMedID 33168752

• Ultralight and fire-extinguishing current collectors for high-energy and high-safety lithium-ion batteries NATURE ENERGY Ye, Y., Chou, L., Liu, Y., Wang, H., Lee, H., Huang, W., Wan, J., Liu, K., Zhou, G., Yang, Y., Yang, A., Xiao, X., Gao, X., Boyle, D., Chen, H., Zhang, W., Kim, S., Cui, Y. 2020; 5 (10): 786–93

  View details for DOI 10.1038/s41560-020-00702-8

  View details for Web of Science ID 000578091500012

• Microclusters of Kinked Silicon Nanowires Synthesized by a Recyclable Iodide Process for High-Performance Lithium-Ion Battery Anodes ADVANCED ENERGY MATERIALS Jeong, Y., Huang, W., Vila, R. A., Huang, W., Wang, J., Kim, S., Kim, Y., Zhao, J., Cui, Y. 2020

  View details for DOI 10.1002/aenm.202002108

  View details for Web of Science ID 000573081400001

• Electrode Design with Integration of High Tortuosity and Sulfur-Philicity for High-Performance Lithium-Sulfur Battery MATTER Chen, H., Zhou, G., Boyle, D., Wan, J., Wang, H., Lin, D., Mackanic, D., Zhang, Z., Kim, S., Lee, H., Wang, H., Huang, W., Ye, Y., Cui, Y. 2020; 2 (6): 1605–20

  View details for DOI 10.1016/j.matt.2020.04.011

  View details for Web of Science ID 000539230500004

• Scalable synthesis of nanoporous silicon microparticles for highly cyclable lithium-ion batteries NANO RESEARCH Wang, J., Huang, W., Kim, Y., Jeong, Y., Kim, S., Heo, J., Lee, H., Liu, B., Nah, J., Cui, Y. 2020

  View details for DOI 10.1007/s12274-020-2770-4

  View details for Web of Science ID 000524406500005