Conjugation-mediated and polarity-switchable interfacial layers for fast cycling of lithium-metal batteries

Abstract

The solid electrolyte interphase (SEI) is a key property of lithium-metal batteries (LMBs), affecting their Coulombic efficiency, rate capability, and cycle life. However, conventional SEIs, primarily formed by the decomposition of lithium salts and fluorinated additives to create inorganic-dominant interphases, suffer from inhomogeneous Li deposition and low ionic conductivity. These intrinsic drawbacks accelerate severe side reactions with the electrolyte, cause rapid capacity fading and accumulation of dead Li, and present safety concerns, particularly under elevated current density. In this study, we unravel the essential role of the SEI on the Li-metal anode in LMBs by creating a conjugation-mediated and polarity-switchable interfacial architecture. The thiophene-embedded polymer-like SEI, formed by in situ electrochemical oligomerization of thiophene, enhances Li⁺ ion conductivity by coordinating with lone electron pairs in sp² orbitals. Concurrently, the conjugated π systems involving sp² hybridized C＝C bonds and S atoms enable switchable polarity of p_zorbitals, facilitating dynamic electron-cloud redistribution during Li plating and stripping. This orbital-level adaptability accelerates Li⁺ migration, suppresses dendritic growth, and stabilizes the Li-metal surface under high-current operation. This study establishes a new paradigm in orbital-engineered interfacial design in LMBs, bridging molecular-scale electronic polarization with macroscopic fast-charging stability. Furthermore, our study underscores that fine-tuning the properties of the SEI and the cathode electrolyte interphase is key to unlocking the transformative potential of LMBs for practical applications.

Keywords

cathode electrolyte interphases / electrolyte additives / fast cycling / lithium metal / nickel-rich cathodes / solid electrolyte interphases

References

[1] Liu B, Zhang J-G, Xu W. Advancing lithium metal batteries. Joule. 2018; 2(5): 833-845.

[2] Zhang R, Li NW, Cheng XB, Yin YX, Zhang Q, Guo YG. Energy storage: advanced micro/nanostructures for lithium metal anodes. Adv Sci. 2017; 4(3):1600445.

[3] Zhang Y, Zuo T-T, Popovic J, et al. Towards better Li metal anodes: challenges and strategies. Mater Today. 2020; 33: 56-74.

[4] Li S, Jiang M, Xie Y, Xu H, Jia J, Li J. Developing high-performance lithium metal anode in liquid electrolytes: challenges and progress. Adv Mater. 2018; 30(17):1706375.

[5] Cheng X-B, Zhang R, Zhao C-Z, Zhang Q. Toward safe lithium metal anode in rechargeable batteries: a review. Chem Rev. 2017; 117(15):10403.

[6] Guo Y, Li H, Zhai T. Reviving lithium-metal anodes for next-generation high-energy batteries. Adv Mater. 2017; 29(29):1700007.

[7] Wu H, Jia H, Wang C, Zhang JG, Xu W. Recent progress in understanding solid electrolyte interphase on lithium metal anodes. Adv Energy Mater. 2021; 11:2003092.

[8] Shan X, Zhong Y, Zhang L, et al. A brief review on solid electrolyte interphase composition characterization technology for lithium metal batteries: challenges and perspectives. J Phys Chem C. 2021; 125(35): 19060-19080.

[9] Xu Y, Dong K, Jie Y, et al. Promoting mechanistic understanding of lithium deposition and solid-electrolyte interphase (SEI) formation using advanced characterization and simulation methods: recent progress, limitations, and future perspectives. Adv Energy Mater. 2022; 12(19):2200398.

[10] Cao W, Li Q, Yu X, Li H. Controlling Li deposition below the interface. eScience. 2022; 2(1): 47-78.

[11] Yasin G, Arif M, Mehtab T, et al. Understanding and suppression strategies toward stable Li metal anode for safe lithium batteries. Energy Storage Mater. 2020; 25:644.

[12] Wang Z, Sun Z, Li J, et al. Insights into the deposition chemistry of Li ions in nonaqueous electrolyte for stable Li anodes. Chem Soc Rev. 2021; 50(5):3178.

[13] Hao F, Verma A, Mukherjee PP. Mechanistic insight into dendrite–SEI interactions for lithium metal electrodes. J Mater Chem A. 2018; 6(40): 19664-19671.

[14] Fang R, Li Y-X, Wang W-W, Gu Y, Mao B-W. Kinetic understanding of lithium metal electrodeposition for lithium anodes. Phys Chem Chem Phys. 2024; 26(36):23544.

[15] Choi N-S, Lee YM, Park JH, Park J-K. Interfacial enhancement between lithium electrode and polymer electrolytes. J Power Sources. 2003; 119: 610-616.

[16] Lee JA, Kim S, Cho Y, et al. Compositionally sequenced interfacial layers for high-energy Li-metal batteries. Adv Sci. 2024; 11(17):2310094.

[17] Gao X, Zhou Y-N, Han D, et al. Thermodynamic understanding of li-dendrite formation. Joule. 2020; 4(9): 1864-1879.

[18] Aslam MK, Niu Y, Hussain T, et al. How to avoid dendrite formation in metal batteries: innovative strategies for dendrite suppression. Nano Energy. 2021; 86:106142.

[19] Wang C, Wang A, Ren L, et al. Controlling Li ion flux through materials innovation for dendrite-free lithium metal anodes. Adv Funct Mater. 2019; 29(49):1905940.

[20] Han F, Westover AS, Yue J, et al. High electronic conductivity as the origin of lithium dendrite formation within solid electrolytes. Nat Energy. 2019; 4(3): 187-196.

[21] Zhang Q-K, Zhang X-Q, Wan J, et al. Homogeneous and mechanically stable solid–electrolyte interphase enabled by trioxane-modulated electrolytes for lithium metal batteries. Nat Energy. 2023; 8(7): 725.

[22] Park HE, Hong CH, Yoon WY. The effect of internal resistance on dendritic growth on lithium metal electrodes in the lithium secondary batteries. J Power Sources. 2008; 178(2): 765-768.

[23] Jana A, Woo SI, Vikrant K, García RE. Electrochemomechanics of lithium dendrite growth. Energ Environ Sci. 2019; 12(12): 3595-3607.

[24] Bai P, Li J, Brushett FR, Bazant MZ. Transition of lithium growth mechanisms in liquid electrolytes. Energ Environ Sci. 2016; 9(10): 3221-3229.

[25] Zhang R, Cheng XB, Zhao CZ, et al. Conductive nanostructured scaffolds render low local current density to inhibit lithium dendrite growth. Adv Mater. 2016; 28(11): 2155-2162.

[26] Zhang S, Li R, Hu N, et al. Tackling realistic Li⁺ flux for high-energy lithium metal batteries. Nat Commun. 2022; 13(1):5431.

[27] Chen C, Liang Q, Wang G, Liu D, Xiong X. Grain-boundary-rich artificial SEI layer for high-rate lithium metal anodes. Adv Funct Mater. 2022; 32(4):2107249.

[28] Wu F, Yuan Y-X, Cheng X-B, et al. Perspectives for restraining harsh lithium dendrite growth: towards robust lithium metal anodes. Energy Storage Mater. 2018; 15: 148-170.

[29] Kim S, Lee J-A, Lee TK, et al. Wide-temperature-range operation of lithium-metal batteries using partially and weakly solvating liquid electrolytes. Energ Environ Sci. 2023; 16(11): 5108-5122.

[30] Kim S, Lee TK, Kwak SK, Choi N-S. Solid electrolyte interphase layers by using lithiophilic and electrochemically active ionic additives for lithium metal anodes. ACS Energy Lett. 2021; 7(1): 67-69.

[31] Chen H, Pei A, Lin D, et al. Uniform high ionic conducting lithium sulfide protection layer for stable lithium metal anode. Adv Energy Mater. 2019; 9(22):1900858.

[32] Zhang S-J, Yin Z-W, Wu Z-Y, et al. Achievement of high-cyclability and high-voltage Li-metal batteries by heterogeneous SEI film with internal ionic conductivity/external electronic insulativity hybrid structure. Energy Storage Mater. 2021; 40: 337-346.

[33] Gao S, Sun F, Liu N, Yang H, Cao P-F. Ionic conductive polymers as artificial solid electrolyte interphase films in Li metal batteries – a review. Mater Today. 2020; 40: 140-159.

[34] Liu Y, Lin D, Yuen PY, et al. An artificial solid electrolyte interphase with high Li-ion conductivity, mechanical strength, and flexibility for stable lithium metal anodes. Adv Mater. 2016; 29(10):1605531.

[35] Lee J-A, Kang H, Kim S, et al. Unveiling degradation mechanisms of anode-free Li-metal batteries. Energy Storage Mater. 2024; 73:103826.

[36] Choi N-S, Lee YM, Seol W, Lee JA, Park J-K. Protective coating of lithium metal electrode for interfacial enhancement with gel polymer electrolyte. Solid State Ion. 2004; 172(1-4): 19-24.

[37] Nishi Y. The development of lithium ion secondary batteries. Chem Record. 2001; 1(5): 406-413.

[38] Kim S, Park G, Lee SJ, et al. Lithium-metal batteries: from fundamental research to industrialization. Adv Mater. 2023; 35(43):2206625.

[39] Lee J, Jeong SH, Nam JS, et al. Toward thin and stable anodes for practical lithium metal batteries: a review, strategies, and perspectives. EcoMat. 2023; 5(12):e12416.

[40] Li Z, Zheng Y, Liao C, et al. Advanced polymer materials for protecting lithium metal anodes of liquid-state and solid-state lithium batteries. Adv Funct Mater. 2024; 34(42):2404427.

[41] Chae B-J, Park JH, Song HJ, et al. Thiophene-initiated polymeric artificial cathode-electrolyte interface for Ni-rich cathode material. Electrochim Acta. 2018; 290: 465-473.

[42] Lin X, Chen Y, Fu Y, et al. Fluorinated thiophene-based electrolyte additives enable a robust cathode electrolyte interphase with conformal homogeneity for a high-voltage LiNi_0.8Co_0.15Al_0.05O₂ cathode. J Phys Chem C. 2024; 128(12): 4988-4996.

[43] Ren W, Huang Y, Li S, et al. 3-Thiopheneboronic acid: an effective additive for regulation on electrode/electrolyte interphase of lithium metal battery with high-loading cathode. Electrochim Acta. 2021; 386:138485.

[44] Li S, Tang R, Hu C, Niu X, Wang L. Graphdiyne-loaded polycaprolactone nanofiber scaffold for peripheral nerve regeneration. J Colloid Interface Sci. 2023; 646: 150-412.

[45] He Y, Zhang Y, Yu P, et al. Ion association tailoring SEI composition for Li metal anode protection. J Energy Chem. 2020; 45: 1.

[46] Wan S, Song K, Chen J, et al. Reductive competition effect-derived solid electrolyte interphase with evenly scattered inorganics enabling ultrahigh rate and long-life span sodium metal batteries. J Am Chem Soc. 2023; 145(39): 21661-21671.

[47] Wang Z, Wang Y, Zhang Z, et al. Building artificial solid-electrolyte interphase with uniform intermolecular ionic bonds toward dendrite-free lithium metal anodes. Adv Funct Mater. 2020; 30(30):2002414.

[48] Wen K, Tan X, Chen T, Chen S, Zhang S. Fast Li-ion transport and uniform Li-ion flux enabled by a double-layered polymer electrolyte for high performance Li metal battery. Energy Storage Mater. 2020; 32: 55-64.

[49] Hagopian A, Doublet M-L, Filhol J-S. Thermodynamic origin of dendrite growth in metal anode batteries. Energ Environ Sci. 2020; 13(12): 5186-5197.

[50] Xue W, Shi Z, Huang M, et al. FSI-inspired solvent and “full fluorosulfonyl” electrolyte for 4 V class lithium-metal batteries. Energ Environ Sci. 2020; 13(1): 212-220.

[51] Dato MA, Edgington J, Hung C, et al. Sulfur solutions: advancing high voltage and high energy lithium batteries with organosulfur electrolytes. Adv Energy Mater. 2024; 14(13):2303794.

[52] Xue W, Huang M, Li Y, et al. Ultra-high-voltage Ni-rich layered cathodes in practical Li metal batteries enabled by a sulfonamide-based electrolyte. Nat Energy. 2021; 6(5): 495.

[53] Yi A, Mamaeva N, Li H, Spudich JL, Rothschild KJ. Resonance Raman study of an anion channelrhodopsin: effects of mutations near the retinylidene Schiff Base. Biochemistry. 2016; 55(16): 2371-2380.

[54] Smith SO, Braiman MS, Myers AB, et al. Vibrational analysis of the all-trans-retinal chromophore in light-adapted bacteriorhodopsin. J Am Chem Soc. 1987; 109(10): 3108-3125.

[55] Smith SO, Hornung I, Van Der Steen R, et al. Are C14-C15 single bond isomerizations of the retinal chromophore involved in the proton-pumping mechanism of bacteriorhodopsin? Proc Natl Acad Sci USA. 1986; 83(4): 967.

[56] Smith SO, Pardoen JA, Lugtenburg J, Mathies RA. Vibrational analysis of the 13-cis-retinal chromophore in dark-adapted bacteriorhodopsin. J Phys Chem. 1987; 91(4): 804-819.

[57] Dong L, Yan HJ, Liu QX, et al. Quantification of charge transport and mass deprivation in solid electrolyte interphase for kinetically-stable low-temperature lithium-ion batteries. Angew Chem Int Ed. 2024; 136:e202411029.

[58] Zabara MA, Katırcı G k, ÜlgÜt B. Operando investigations of the interfacial electrochemical kinetics of metallic lithium anodes via temperature-dependent electrochemical impedance spectroscopy. J Phys Chem C. 2022; 126(27): 10968.

[59] Churikov A. Transfer mechanism in solid-electrolyte layers on lithium: influence of temperature and polarization. Electrochim Acta. 2001; 46(15): 2415.

[60] Xu K. Electrolytes and interphases in Li-ion batteries and beyond. Chem Rev. 2014; 114(23): 11503.

[61] Yamamoto T. Molecular assembly and properties of polythiophenes. NPG Asia Mater. 2010; 2(2): 54.

[62] Furukawa Y, Akimoto M, Harada I. Vibrational key bands and electrical conductivity of polythiophene. Synth Met. 1987; 18(1-3): 151.

[63] Guo R, Gallant BM. Li₂O solid electrolyte interphase: probing transport properties at the chemical potential of lithium. Chem Mater. 2020; 32(13): 5525.

[64] Wang S, Liu D, Cai X, et al. Promoting the reversibility of lithium ion/lithium metal hybrid graphite anode by regulating solid electrolyte interface. Nano Energy. 2021; 90:106510.

[65] Zhang Z, Said S, Smith K, et al. Characterizing batteries by in situ electrochemical atomic force microscopy: a critical review. Adv Energy Mater. 2021; 11(38):2101518.

[66] Um JH, Yu SH. Lithium metal batteries: unraveling the mechanisms of lithium metal plating/stripping via in situ/operando analytical techniques. Adv Energy Mater. 2021; 11(27):2003004.

[67] Balke N, Jesse S, Morozovska A, et al. Nanoscale mapping of ion diffusion in a lithium-ion battery cathode. Nat Nanotechnol. 2010; 5(10): 749-754.

[68] Joo S, Jeong U, Gong C, Hong S. Bridging mechanical and electrical analyses in AFM: advances, techniques, and applications. Acc Mater Res. 2024; 6(1): 17-27.

[69] Kitada K, Murayama H, Fukuda K, et al. Factors determining the packing-limitation of active materials in the composite electrode of lithium-ion batteries. J Power Sources. 2016; 301: 11-17.

[70] Kim Y, Kim M, Lee T, et al. Investigation of mass loading of cathode materials for high energy lithium-ion batteries. Electrochem Commun. 2023; 147:107437.

[71] Wu F, Liu M, Li Y, et al. High-mass-loading electrodes for advanced secondary batteries and supercapacitors. Electrochem Energ Rev. 2021; 4(2): 382.

[72] Chen Y, Yu Z, Rudnicki P, et al. Steric effect tuned ion solvation enabling stable cycling of high-voltage lithium metal battery. J Am Chem Soc. 2021; 143(44): 18703.

[73] Shi P, Liu F, Feng Y, Zhou J, Rui X, Yu Y. The synergetic effect of lithium bisoxalatodifluorophosphate and fluoroethylene carbonate on dendrite suppression for fast charging lithium metal batteries. Small. 2020; 16(30):2001989.

[74] Zhang W, Wu Q, Huang J, et al. Colossal granular lithium deposits enabled by the grain-coarsening effect for high-efficiency lithium metal full batteries. Adv Mater. 2020; 32(24):2001740.

[75] Fang W, Wen Z, Chen L, et al. Constructing inorganic-rich solid electrolyte interphase via abundant anionic solvation sheath in commercial carbonate electrolytes. Nano Energy. 2022; 104:107881.

[76] Xia M, Jiao T, Liu G, et al. Rational design of electrolyte solvation structure for stable cycling and fast charging lithium metal batteries. J Power Sources. 2022; 548:232106.

[77] Zhang G, Chang J, Wang L, et al. A monofluoride ether-based electrolyte solution for fast-charging and low-temperature non-aqueous lithium metal batteries. Nat Commun. 2023; 14(1):1081.

[78] Boyle DT, Huang W, Wang H, et al. Corrosion of lithium metal anodes during calendar ageing and its microscopic origins. Nat Energy. 2021; 6(5): 487-494.

[79] Kwon H, Kim H, Hwang J, et al. Borate–pyran lean electrolyte-based Li-metal batteries with minimal Li corrosion. Nat Energy. 2024; 9(1): 57-69.

[80] Zaban A, Zinigrad E, Aurbach D. Impedance spectroscopy of Li electrodes. 4. A general simple model of the Li−solution interphase in polar aprotic systems. J Phys Chem. 1996; 100(8): 3089.

[81] Melitz W, Shen J, Kummel AC, Lee S. Kelvin probe force microscopy and its application. Surf Sci Rep. 2011; 66(1): 1-27.

[82] Park G, Moon H, Shin S, et al. Spatially uniform lithiation enabled by single-walled carbon nanotubes. ACS Energy Lett. 2023; 8(7): 3154.

[83] Wang W-W, Gu Y, Yan H, et al. Evaluating solid-electrolyte interphases for lithium and lithium-free anodes from nanoindentation features. Chem. 2020; 6(10): 2728-2745.

[84] Tan YH, Liu Z, Zheng JH, et al. Inorganic composition modulation of solid electrolyte interphase for fast charging lithium metal batteries. Adv Mater. 2024; 36(30):2404815.

[85] Villeneuve-Faure C, Boudou L, Makasheva K, Teyssedre G. Methodology for extraction of space charge density profiles at nanoscale from Kelvin probe force microscopy measurements. Nanotechnology. 2017; 28(50):505701.

[86] Delley B. DMol, a standard tool for density functional calculations: review and advances. Theor Comput Chem. 1995; 2: 221-254.

[87] Delley B. An all-electron numerical method for solving the local density functional for polyatomic molecules. J Chem Phys. 1990; 92(1): 508.

[88] Stephens PJ, Devlin FJ, Chabalowski CF, Frisch MJ. Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields. J Phys Chem. 1994; 98(45): 11623.

[89] Tkatchenko A, Scheffler M. Accurate molecular van der Waals interactions from ground-state electron density and free-atom reference data. Phys Rev Lett. 2009; 102(7):073005.

[90] Marzari N, Mostofi AA, Yates JR, Souza I, Vanderbilt D. Maximally localized Wannier functions: theory and applications. Rev Mod Phys. 2012; 84(4): 1419-1475.

[91] Mostofi AA, Yates JR, Pizzi G, et al. An updated version of wannier90: a tool for obtaining maximally-localised Wannier functions. Comput Phys Commun. 2014; 185(8): 2309-2310.

[92] Hai-Rong M, Ping L, Qing-Quan G, Hui-Li L. Formation mechanism and binding energy for body-centred regular octahedral structure of Li₇ cluster. Commun Theor Phys. 2007; 48(4): 717-720.

[93] Kresse G, Furthmüller J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys Rev B. 1996; 54(16): 11169-11186.

[94] Kresse G, Furthmüller J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput Mater Sci. 1996; 6(1): 15-50.

[95] Perdew JP, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys Rev Lett. 1996; 77(18): 3865-3868.

[96] Kresse G, Joubert D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys Rev B. 1999; 59(3): 1758-1775.

RIGHTS & PERMISSIONS

2026 The Author(s). InfoMat published by UESTC and John Wiley & Sons Australia, Ltd.