Modification engineering of “polymer-in-salt” electrolytes toward high-stability solid-state lithium batteries

Abstract

Solid-state lithium batteries have been regarded as a promising candidate to become the power supply for electric vehicles and smart grids due to their high energy density and reliable safety. The solid polymer electrolytes (SPEs) with light and thin features show distinctive potential in boosting the available energy density at battery level, whereas their ionic conductivity smaller than 10^-4~10^-5 S cm^-1 at room temperature constrains the ionic transfer kinetics, leading to low power density and short cycling life. To overcome such problem, the increase of lithium-salt concentration over 50 wt% evokes the conversion from “salt-in-polymer” to “polymer-in-salt” (PIS) of SPEs, which can make additional ionic migration pathway and thus the improved ionic conductivity. However, the abundant lithium-salt may also cause the reduced electrochemical window as well as mechanical properties, which restricts the compatibility with high-voltage cathodes and lowers the operation safety. In this review, the structures and characteristics of PIS electrolytes have been elucidated through clarifying the correlation between lithium-salt and polymer matrix. Then, the recent modification engineering progresses on PIS electrolytes are addressed from the aspects of component regulations including polymer matrices, lithium salts and fillers, novel preparation techniques, and extended application scenarios. The crucial challenges and possible research directions are finally proposed for the PIS electrolytes regarding both science and practical perspectives.

Keywords

electrolytes / interface compatibility / ionic conductivity / polymer-in-salt / solid state lithium batteries

References

[1] Gupta A, Manthiram A. Designing advanced lithium-based batteries for low-temperature conditions. Adv Energy Mater. 2020;10(38):2001972.

[2] Zhou G, Li F, Cheng H.-M. Progress in flexible lithium batteries and future prospects. Energy Environ Sci. 2014;7(4):1307-1338.

[3] Nayak PK, Yang L, Brehm W, Adelhelm P. From lithium-ion to sodium-ion batteries: advantages challenges and surprises. Angew Chem Int Ed. 2018;57(1):102-120.

[4] Liu X, Bi Z, Wan Y, Guo X. Composition regulation of polyacrylonitrile-based polymer electrolytes enabling dual-interfacially stable solid-state lithium batteries. J Colloid Interface Sci. 2024;665:582-591.

[5] Bi Z, Shi R, Liu X, Liu K, Jia M, Guo X. In situ conversion reaction triggered Alloy@Antiperovskite hybrid layers for lithiophilic and robust lithium/garnet interfaces. Adv Funct Mater. 2023;33(43):2307701.

[6] Liang H, Wang L, Wang A, et al. Tailoring practically accessible polymer/inorganic composite electrolytes for all-solid-state lithium metal batteries: a review. Nano-Micro Lett. 2023;15(1):42.

[7] Liu S, Liu W, Ba D, et al. Filler-integrated composite polymer electrolyte for solid-state lithium batteries. Adv Mater. 2023;35(2):e2110423.

[8] Pan J, Zhao P, Wang N, Huang F, Dou S. Research progress in stable interfacial constructions between composite polymer electrolytes and electrodes. Energy Environ Sci. 2022;15(7):2753-2775.

[9] Ates T, Keller M, Kulisch J, Adermann T, Passerini S. Development of an all-solid-state lithium battery by slurry-coating procedures using a sulfidic electrolyte. Energy Storage Mater. 2019;17:204-210.

[10] Mu S, Bi Z, Gao S, Guo X. Combination of organic and inorganic electrolytes for composite membranes toward applicable solid lithium batteries. Chem Res Chin Univ. 2021;37(2):246-253.

[11] Bi Z, Huang W, Mu S, Sun W, Zhao N, Guo X. Dual-interface reinforced flexible solid garnet batteries enabled by in-situ solidified gel polymer electrolytes. Nano Energy. 2021;90:106498.

[12] Xia Q, Zan F, Zhang Q, et al. All-solid-state thin film lithium/lithium-ion microbatteries for powering the internet of things. Adv Mater. 2023;35(2):e2200538.

[13] Bi Z, Sun Q, Jia M, Zuo M, Zhao N, Guo X. Molten salt driven conversion reaction enabling lithiophilic and air-stable garnet surface for solid-state lithium batteries. Adv Funct Mater. 2022;32(52):2208751.

[14] Narayanan S, Ulissi U, Gibson JS, Chart YA, Weatherup RS, Pasta M. Effect of current density on the solid electrolyte interphase formation at the lithiummid R:Li₆PS₅Cl interface. Nat Commun. 2022;13(1):7237.

[15] Sun H, Kang S, Cui L. Prospects of LLZO type solid electrolyte: from material design to battery application. Chem Eng J. 2023;454:140375.

[16] Liu Y, Meng J, Lei M, Yu Y, Lai C, Li C. Alloyable viscous fluid for interface welding of garnet electrolyte to enable highly reversible fluoride conversion solid state batteries. Adv Funct Mater. 2022;33(4):2208013.

[17] Zhang Z, Wang J, Jin Y, Liu G, Yang S, Yao X. Insights on lithium plating behavior in graphite-based all-solid-state lithium-ion batteries. Energy Storage Mater. 2023;54:845-853.

[18] Tang X, Xu X, Bai M, et al. Ultrafast laser-induced cathode/electrolyte interphase for high-voltage poly(ethylene oxide)-based solid batteries. Adv Funct Mater. 2022;33(5):2210465.

[19] Wu L, Pei F, Cheng D, et al. Flame-retardant polyurethane-based solid-state polymer electrolytes enabled by covalent bonding for lithium metal batteries. Adv Funct Mater. 2023;34(16):2310084.

[20] Lu G, Nai J, Luan D, Tao X, Lou XW. Surface engineering toward stable lithium metal anodes. Sci Adv. 2023;9(14):eadf1550.

[21] Bi Z, Guo X. Solidification for solid-state lithium batteries with high energy density and long cycle life. Energy Mater. 2022;2:200011.

[22] Zhao X, Shen L, Zhang N, et al. Stable binder boosting sulfide solid electrolyte thin membrane for all-solid-state lithium batteries. Energy Mater Adv. 2024;5:0074.

[23] Zhao X, Xiang P, Wu J, et al. Toluene tolerated Li_9.88GeP_1.96Sb_0.04S_11.88Cl_0.12 solid electrolyte toward ultrathin membranes for all-solid-state lithium batteries. Nano Lett. 2023;23(1):227-234.

[24] Zhang Z, Wu L, Zhou D, Weng W, Yao X. Flexible sulfide electrolyte thin membrane with ultrahigh ionic conductivity for all-solid-state lithium batteries. Nano Lett. 2021;21(12):5233-5239.

[25] Li X, Kim JT, Luo J, et al. Structural regulation of halide superionic conductors for all-solid-state lithium batteries. Nat Commun. 2024;15(1):53.

[26] Guo Q, Xu F, Shen L, et al. 20 µm-thick Li_6.4La₃Zr_1.4Ta_0.6O₁₂-based flexible solid electrolytes for all-solid-state lithium batteries. Energy Mater Adv. 2022;2022:9753506.

[27] Guo Q, Xu F, Shen L, et al. Poly(ethylene glycol) brush on Li_6.4La₃Zr_1.4Ta_0.6O₁₂ towards intimate interfacial compatibility in composite polymer electrolyte for flexible all-solid-state lithium metal batteries. J Power Sources. 2021;498:229934.

[28] Chen L, Gu T, Ma J, et al. In situ construction of Li₃N-enriched interface enabling ultra-stable solid-state LiNi_0.8CO_0.1MN_0.1O₂/lithium metal batteries. Nano Energy. 2022;100:107470.

[29] Huang T, Xiong W, Ye X, et al. A cerium-doped NASICON chemically coupled poly(vinylidene fluoride-hexafluoropropylene)-based polymer electrolyte for high-rate and high-voltage quasi-solid-state lithium metal batteries. J Energy Chem. 2022;73:311-321.

[30] Liang X, Wang L, Wu X, et al. Solid-state electrolytes for solid-state lithium-sulfur batteries: comparisons advances and prospects. J Energy Chem. 2022;73:370-386.

[31] Liu Q, Yang G, Li X, et al. Polymer electrolytes based on interactions between [solvent-Li⁺] complex and solvent-modified polymer. Energy Storage Mater. 2022;51:443-452.

[32] Gao H, Grundish NS, Zhao Y, Zhou A, Goodenough JB. Formation of stable interphase of polymer-in-salt electrolyte in all-solid-state lithium batteries. Energy Mater Adv. 2021;2021:1932952.

[33] McLin MG, Angell CA. Frequency-dependent conductivity, relaxation times, and the conductivity/viscosity coupling problem, in polymer-electrolyte solutions: LiClO₄ and NaCF₃SO₃ in PPO 4000. Solid State Ionics. 1992;53-56:1027-1036.

[34] Angell CA, Liu C, Sanchez E. Rubbery solid electrolytes with dominant cationic transport and high ambient conductivity. Nature. 1993;362(6416):137-139.

[35] Liu W, Yi C, Li L, et al. Designing polymer-in-salt electrolyte and fully infiltrated 3D electrode for integrated solid-state lithium batteries. Angew Chem Int Ed. 2021;60(23):12931-12940.

[36] Zhang J, Zeng Y, Li Q, et al. Polymer-in-salt electrolyte enables ultrahigh ionic conductivity for advanced solid-state lithium metal batteries. Energy Storage Mater. 2023;54:440-449.

[37] Zhao Y, Qin Y, Da X, et al. High lithium salt content PVDF-based solid-state composite polymer electrolyte enhanced by h-BN nanosheets. ChemSusChem. 2022;15(24):e202201554.

[38] Lin W, Chen D, Yu J. Manipulating the ionic conductivity and interfacial compatibility of polymer-in-dual-salt electrolytes enables extended-temperature quasi-solid metal batteries. J Colloid Interface Sci. 2024;666:189-200.

[39] Zhang H, Li L, Kang G, Lu N, Wang S, Wang G. A flexible and mechanical robust all-solid-state polymer electrolyte with microphase separated structure for lithium-ion battery. ACS Appl Mater Interfaces. 2024;16(19):24671-24682.

[40] Pan L, Feng S, Sun H, et al. Ultrathin mechanically durable and scalable polymer-in-salt solid electrolyte for high-rate lithium metal batteries. Small. 2024:e2400272.

[41] Li C, Zhang Q, Sheng J, et al. A quasi-intercalation reaction for fast sulfur redox kinetics in solid-state lithium-sulfur batteries. Energy Environ Sci. 2022;15(10):4289-4300.

[42] Zou L, Shi K, Liu H, et al. Polybenzimidazole-reinforced polyethylene oxide-based polymer-in-salt electrolytes enabling excellent structural stability and superior electrochemical performance for lithium metal batteries. Chem Eng J. 2023;465:142794.

[43] Chen L, Fan LZ. Dendrite-free Li metal deposition in all-solid-state lithium sulfur batteries with polymer-in-salt polysiloxane electrolyte. Energy Storage Mater. 2018;15:37-45.

[44] You D, Hu W, Song L, Wei W, Xiong H. High-energy metallic lithium batteries enabled by polymer-in-salt electrolytes of cyclic carbonate substituted polyethers. ACS Appl Polym Mater. 2022;4(11):8584-8593.

[45] Zhou Z, Tao Z, Chen R, et al. Elastomeric electrolyte for high capacity and long-cycle-life solid-state lithium metal battery. Small Methods. 2023;7(4):e2201328.

[46] Bai S, Zhang X, Chen Z, Lin J, Wang Q, Zhang Y. Design of polymer-in-salt electrolyte for solid state lithium battery with wide working temperature range. ChemistrySelect. 2022;7(21):e202201571.

[47] Wang Y, Li Z, Xu H, et al. Polymer-in-Salt electrolyte from poly(caprolactone)-graft-polyrotaxane for Ni-rich lithium metal batteries at room temperature. ACS Appl Mater Interfaces. 2023;15(26):31552-31560.

[48] Pelz A, Dörr TS, Zhang P, et al. Self-assembled block copolymer electrolytes: enabling superior ambient cationic conductivity and electrochemical stability. Chem Mater. 2018;31(1):277-285.

[49] Min X, Han C, Zhang S, et al. Highly oxidative-resistant cyano-functionalized lithium borate salt for enhanced cycling performance of practical lithium-ion batteries. Angew Chem Int Ed. 2023;62(34):e202302664.

[50] Zhou Q, Ma J, Dong S, Li X, Cui G. Intermolecular Chemistry in solid polymer electrolytes for high-energy-density lithium batteries. Adv Mater. 2019;31(50):e1902029.

[51] Goodenough JB, Kim Y. Challenges for rechargeable Li batteries. Chem Mater. 2009;22(3):587-603.

[52] Hou J, Yang M, Wang D, Zhang J. Fundamentals and challenges of lithium ion batteries at temperatures between −40 and 60°C. Adv Energy Mater. 2020;10(18):1904152.

[53] Gao Y, Wang D, Li YC, Yu Z, Mallouk TE, Wang D. Salt-based organic-inorganic nanocomposites: towards A stable lithium metal/Li₁₀GeP₂S₁₂ solid electrolyte interface. Angew Chem Int Ed Engl. 2018;57(41):13608-13612.

[54] Liu L, Qi X, Yin S, et al. In situ formation of a stable interface in solid-state batteries. ACS Energy Lett. 2019;4(7):1650-1657.

[55] Umeshbabu E, Zheng B, Zhu J, Wang H, Li Y, Yang Y. Stable cycling lithium-sulfur solid batteries with enhanced Li/Li₁₀GeP₂S₁₂ solid electrolyte interface stability. ACS Appl Mater Interfaces. 2019;11(20):18436-18447.

[56] Li H, Du Y, Wu X, Xie J, Lian F. Developing “polymer-in-salt”high voltage electrolyte based on composite lithium salts for solid-state Li metal batteries. Adv Funct Mater. 2021;31(41):2103049.

[57] Zygadło-Monikowska E, Florjańczyk Z, Kubisa P, et al. Mixture of LiBF₄ and lithium difluoro(oxalato)borate for application as a new electrolyte for lithium-ion batteries. J Power Sources. 2010;195(18):6202-6206.

[58] Bi Z, Mu S, Zhao N, Sun W, Huang W, Guo X. Cathode supported solid lithium batteries enabling high energy density and stable cyclability. Energy Storage Mater. 2021;35:512-519.

[59] Liu L, Zhang D, Zhao J, et al. Synergistic effect of lithium salts with fillers and solvents in composite electrolytes for superior room-temperature solid-state lithium batteries. ACS Appl Energy Mater. 2022;5(2):2484-2494.

[60] Fan R, Liu C, He K, et al. Versatile strategy for realizing flexible room-temperature all-solid-state battery through a synergistic combination of salt affluent PEO and Li_6.75La₃Zr_1.75Ta_0.25O₁₂ nanofibers. ACS Appl Mater Interfaces. 2020;12(6):7222-7231.

[61] Zhang L, Xu X, Jiang S, et al. Halloysite nanotubes modified poly(vinylidenefluoride-co-hexafluoropropylene)-based polymer-in-salt electrolyte to achieve high-performance Li metal batteries. J Colloid Interface Sci. 2023;645:45-54.

[62] Shi K, Zheng D, Guo Z, Yang Z, Zhang W. Polypropylene separator-reinforced polymer-in-salt solid composite electrolytes for high-performance lithium ion batteries at room temperature. Sustain Energy Fuels. 2022;6(24):5503-5513.

[63] Chen F, Wang X, Armand M, Forsyth M. Cationic polymer-in-salt electrolytes for fast metal ion conduction and solid-state battery applications. Nat Mater. 2022;21(10):1175-1182.

[64] Zhao Y, Meng X, Kang Q, et al. Integrating a three-dimensional Cu₂MoS₄ electrode and solid-state polymer electrolyte for sodium-ion batteries. Chem Eng J. 2022;450:137903.

[65] Yan K, Fan Y, Hu F, et al. “Polymer-in-Salt”solid electrolyte enabled by fast phase transition route for stable Zn batteries. Adv Funct Mater. 2023;34(2):2307740.

[66] Wu H, Gao P, Jia H, et al. A polymer-in-salt electrolyte with enhanced oxidative stability for lithium metal polymer batteries. ACS Appl Mater Interfaces. 2021;13(27):31583-31593.

[67] Sun M, Zeng Z, Zhong W, et al. In situ prepared “polymer-in-salt”electrolytes enabling high-voltage lithium metal batteries. J Mater Chem A. 2022;10(21):11732-11741.

[68] Tu H, Li L, Hu Y, et al. Non-flammable liquid polymer-in-salt electrolyte enabling secure and dendrite-free lithium metal battery. Chem Eng J. 2022;434:134647.

[69] Yang H, Zhang B, Jing M, et al. In situ catalytic polymerization of a highly homogeneous PDOL composite electrolyte for long-cycle high-voltage solid-state lithium batteries. Adv Energy Mater. 2022;12(39):2201762.

[70] Yang H, Jing M, Wang L, Xu H, Yan X, He X. PDOL-based solid electrolyte toward practical application: opportunities and challenges. Nano-Micro Lett. 2024;16(1):127.

[71] Xie J, Xu H, Wang Q, et al. A polymer-in-salt electrolyte enables room temperature lithium metal batteries. J Electrochem Soc. 2022;169(4):040562.

[72] Pan L, Sun S, Yu G, et al. Stabilizing solid electrolyte/Li interface via polymer-in-salt artificial protection layer for high-rate and stable lithium metal batteries. Chem Eng J. 2022;449:137682.

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