Corresponding Author

Xiao-Dong Wang(wangxd99@gmail.com);
Guang Feng(gfeng@hust.edu.cn)


Over recent years, oligomer ionic liquids (OILs), a novel class of ionic liquids, are becoming preferential electrolytes for high-performance energy-storage devices, such as supercapacitors with enhanced energy density and non-flammable lithium-ion batteries (LIBs). Herein, structures, properties, and their associations of the up-to-the-minute formulated OILs are systematically summarized and elaborately interpreted, especially for dicationic ionic liquids and tricationic ionic liquids. The physicochemical and electrochemical properties of OIL-based electrolytes are presented and analyzed, which are vitally important for supercapacitors and LIBs. Subsequently, the applications of OILs as electrolytes for supercapacitors and LIBs are summarized, with the comparisons of the energy-storage mechanisms and performance between OILs and MILs electrolytes in supercapacitors. Meanwhile, the optimization of the dynamic performance of OILs electrolytes is provided. Finally, the main difficulties and probable perspectives of OIL-based electrolytes are presented for future work. This review would contribute to a deep understanding of OILs and design optimized OIL-based electrolytes for energy storage systems.

Graphical Abstract


oligomer ionic liquids, properties and structures, supercapacitors, lithium-ion batteries

Publication Date


Online Available Date


Revised Date


Received Date



[1] Koohi-Fayegh S, Rosen M A. A review of energy storage types, applications and recent developments[J]. J. Energy Storage, 2020, 27: 101047.

[2] Abbas Q, Mirzaeian M, Hunt M R C, Hall P, Raza R. Current state and future prospects for electrochemical energy storage and conversion systems[J]. Energies, 2020, 13(21): 5847.

[3] Behabtu H A, Messagie M, Coosemans T, Berecibar M, Anlay Fante K, Kebede A A, Mierlo J V. A review of energy storage technologies’ application potentials in renewable energy sources grid integration[J]. Sustainability, 2020, 12(24): 10511.

[4] Simon P, Gogotsi Y, Dunn B. Where do batteries end and supercapacitors begin?[J]. Science, 2014, 343: 1210-1211.

[5] Yang Y S. A review of electrochemical energy storage researches in the past 22 years[J]. J. Electrochem., 2020, 26(4): 443-463.

[6] Daud M Z, Mohamed A, Hannan M A. An improved control method of battery energy storage system for hourly dispatch of photovoltaic power sources[J]. Energy Convers. Manage., 2013, 73: 256-270.

[7] Hannan M A, Lipu M, Hussain A, Mohamed A. A review of lithium-ion battery state of charge estimation and management system in electric vehicle applications: challenges and recommendations[J]. Renew. Sustain Energy Rev., 2017, 78: 834-854.

[8] Niu H Z, Wang L, Guan P, Zhang N, Yan C R, Ding M L, Guo X L, Huang T T, Hu X L. Recent advances in application of ionic liquids in electrolyte of lithium ion batteries[J]. J. Energy Storage, 2021, 40: 102659.

[9] Arbizzani C, Gabrielli G, Mastragostino M. Thermal stability and flammability of electrolytes for lithium-ion batteries[J]. J. Power Sources, 2011, 196(10): 4801-4805.

[10] Lin X, Salari M, Arava L M R, Ajayan P M, Grinstaff M W. High temperature electrical energy storage: Advances, challenges, and frontiers[J]. Chem. Soc. Rev., 2016, 45(21): 5848-5887.
pmid: 27775120

[11] Wang Q S, Jiang L H, Yu Y, Sun J H. Progress of enhancing the safety of lithium ion battery from the electrolyte aspect[J]. Nano Energy, 2019, 55: 93-114.

[12] Huang S F, Zhu X L, Sarkar S, Zhao Y F. Challenges and opportunities for supercapacitors[J]. APL Mater., 2019, 7(10): 100901.

[13] Chen Y Q, Kang Y Q, Zhao Y, Wang L, Liu J L, Li Y X, Liang Z, He X M, Li X, Tavajohi N, Li B H. A review of lithium-ion battery safety concerns: The issues, strategies, and testing standards[J]. J. Energy Chem., 2021, 59: 83-99.

[14] Zhang Q K, Zhang X Q, Yuan H, Huang J Q. Thermally stable and nonflammable electrolytes for lithium metal batteries: Progress and perspectives[J]. Small Science, 2021, 1(10): 2100058.

[15] Poonam, Sharma K, Arora A, Tripathi S K. Review of supercapacitors: Materials and devices[J]. J. Energy Storage, 2019, 21: 801-825.
doi: 10.1016/j.est.2019.01.010

[16] Sharma P, Kumar V. Current technology of supercapacitors: A review[J]. J. Electron. Mater., 2020, 49(6): 3520-3532.

[17] Horn M, MacLeod J, Liu M, Webb J, Motta N. Supercapacitors: A new source of power for electric cars?[J]. Econ. Anal. Policy, 2019, 61: 93-103.
doi: 10.1016/j.eap.2018.08.003

[18] Wang R, Yao M J, Niu Z Q. Smart supercapacitors from materials to devices[J]. InfoMat, 2020, 2(1): 113-125.

[19] Ma H L, Zhang Y Y, Shen M H. Application and prospect of supercapacitors in internet of energy(IOE)[J]. J. Energy Storage, 2021, 44: 103299.

[20] Yang Y C, Han Y H, Jiang W K, Zhang Y Y, Xu Y M, Ahmed A M. Application of the supercapacitor for energy storage in china: Role and strategy[J]. Appl. Sci.-Basel, 2022, 12(1): 354.

[21] Wang Y G, Song Y F, Xia Y Y. Electrochemical capacitors: Mechanism, materials, systems, characterization and applications[J]. Chem. Soc. Rev., 2016, 45(21): 5925-5950.
pmid: 27545205

[22] Miller J R, Simon P. Materials science. Electrochemical capacitors for energy management[J]. Science, 2008, 321(5889): 651-652.
doi: 10.1126/science.1158736 pmid: 18669852

[23] Pal B, Yang S Y, Ramesh S, Thangadurai V, Jose R. Ele-ctrolyte selection for supercapacitive devices: A critical review[J]. Nanoscale Adv., 2019, 1(10): 3807-3835.

[24] Zhang J Y, Yao X H, Misra R K, Cai Q, Zhao Y L. Pro-gress in electrolytes for beyond-lithium-ion batteries[J]. J. Mater. Sci. Technol., 2020, 44: 237-257.
doi: 10.1016/j.jmst.2020.01.017

[25] Tang X, Lv S Y, Jiang K, Zhou G H, Liu X M. Recent development of ionic liquid-based electrolytes in lithium-ion batteries[J]. J. Power Sources, 2022, 542: 231792.

[26] Yu L P, Chen G Z. Ionic liquid-based electrolytes for supercapacitor and supercapattery[J]. Front. Chem., 2019, 7: 272.
doi: 10.3389/fchem.2019.00272 pmid: 31058143

[27] Lauw Y, Horne M D, Rodopoulos T, Nelson A, Leermakers F A M. Electrical double-layer capacitance in room temperature ionic liquids: Ion-size and specific adsorption effects[J]. J. Phys. Chem. B, 2010, 114(34): 11149-11154.

[28] Lamperski S, Outhwaite C W, Bhuiyan L B. The electric double-layer differential capacitance at and near zero surface charge for a restricted primitive model electrolyte[J]. J. Phys. Chem. B, 2009, 113(26): 8925-8929.

[29] Pinilla C, Del Popolo M G, Kohanoff J, Lynden-Bell R M. Polarization relaxation in an ionic liquid confined between electrified walls[J]. J. Phys. Chem. B, 2007, 111(18): 4877-4884.

[30] Baldelli S. Surface structure at the ionic liquid-electrified metal interface[J]. Acc. Chem. Res., 2008, 41(3): 421-431.

[31] Wang Y L, Li B, Sarman S, Mocci F, Fayer M D. Micro-structural and dynamical heterogeneities in ionic liquids[J]. Chem. Rev., 2020, 120: 5798-5877.

[32] Wang X H, Salari M, Jiang D E, Varela J C, Anasori B, Wesolowskl D J, Dai S, Grinstaff M W, Gogotsi Y. Electrode material-ionic liquid coupling for electrochemical energy storage[J]. Nat. Rev. Mater., 2020, 5(11): 787-808.

[33] Anderson J L, Ding R F, Ellern A, Armstrong D W. Structure and properties of high stability geminal dicationic ionic liquids[J]. J. Am. Chem. Soc., 2005, 127(2): 593-604.
pmid: 15643883

[34] Liu Q B, Rantwijk F V, Sheldon R A. Synthesis and application of dicationic ionic liquids[J]. J. Chem. Technol. Biotechnol., 2006, 81: 401-405.

[35] Guglielmero L, Mezzetta A, Guazzelli L, Pomelli C S, D’Andrea F, Chiappe C. Systematic synthesis and properties evaluation of dicationic ionic liquids, and a glance into a potential new field[J]. Front. Chem., 2018, 6: 612.
doi: 10.3389/fchem.2018.00612 pmid: 30619821

[36] Bhatt D R, Maheria K C, Parikh J K. A microwave assisted one pot synthesis of novel ammonium based dicationic ionic liquids[J]. RSC Adv., 2015, 5(16): 12139-12143.

[37] Zhang Z X, Yang L, Luo S C, Tian M, Tachibana K, Kamijima K. Ionic liquids based on aliphatic tetraalkylammonium dications and TFSI anion as potential electrolytes[J]. J. Power Sources, 2007, 167: 217-222.

[38] Wang R, Jin CM, Twamley B, Shreeve J M. Syntheses and characterization of unsymmetric dicationic salts incorporating imidazolium and triazolium functionalities[J]. Inorg. Chem., 2006, 45: 6396-6403.
pmid: 16878951

[39] Payagala T, Huang J, Breitbach Z S, Sharma P S, Armstrong D W. Unsymmetrical dicationic ionic liquids: Manipuation of physicochemical properties using specific structural architectures[J]. Chem. Mater., 2007, 19: 5848-5850.

[40] Chang J C, Ho W Y, Sun I W, Tung Y L, Tsui M C, Wu T Y, Liang S S. Synthesis and characterization of dicationic ionic liquids that contain both hydrophilic and hydrophobic anions[J]. Tetrahedron, 2010, 66(32): 6150-6155.

[41] Brown P, Butts C P, Eastoe J, Hernandez E P, Machado F L D A, Oliveira R J D. Dication magnetic ionic liquids with tuneable heteroanions[J]. Chem. Commun., 2013, 49: 2765.

[42] Zhou N, Zhao G Y, Dong K, Sun J, Shao H W. Investigations on a series of novel ionic liquids containing the [closo-B12Cl12]2- dianion[J]. RSC Adv., 2012, 2: 9830-9838.

[43] Kuhn B L, Osmari B F, Heinen T M, Bonacorso HG, Zanatta N, Nielsen S O, Ranathunga D T S, Villetti M A, Frizzo C P. Dicationic imidazolium-based dicarboxylate ionic liquids: Thermophysical properties and solubility[J]. J. Mol. Liq., 2020, 308: 112983.

[44] Sharma P S, Payagala T, Wanigasekara E, Wijeratne A B, Huang J M, Armstrong D W. Trigonal tricationic ionic liquids: Molecular engineering of trications to control physicochemical properties[J]. Chem. Mater., 2008, 20(13): 4182-4184.

[45] Wanigasekara E, Zhang X T, Nanayakkara Y, Payagala T, Moon H, Armstrong D W. Linear tricationic room-temperature ionic liquids: Synthesis, physiochemical properties, and electrowetting properties[J]. ACS Appl. Mater. Interfaces, 2009, 1(10): 2126-2133.

[46] López F I, Ibarra-Sanchez L, Domínguez-Esquivel J M, Miranda-Olvera A D, Bravo R H, Lagunas-Rivera S. Experimental and theoretical study on the synthesis and thermophysical properties of newer tricationic ionic liquids[J]. J. Mol. Struct., 2022, 1263: 133164.

[47] Mogurampelly S, Keith J R, Ganesan V. Mechanisms underlying ion transport in polymerized ionic liquids[J]. J. Am. Chem. Soc., 2017, 139(28): 9511-9514.
doi: 10.1021/jacs.7b05579 pmid: 28686437

[48] Yuan J, Mecerreyes D, Antonietti M. Poly(ionic liquid)s: An update[J]. Prog. Polym. Sci., 2013, 38(7): 1009-1036.

[49] Mecerreyes D. Polymeric ionic liquids: Broadening the properties and applications of polyelectrolytes[J]. Prog. Polym. Sci., 2011, 36(12): 1629-1648.

[50] Qian W, Texter J, Feng Y. Frontiers in poly(ionic liquid)s: Syntheses and applications[J]. Chem. Soc. Rev., 2017, 46.(4): 1124-1159

[51] Matsumoto M, Saito Y, Park C Y, Fukushima T, Aida T. Ultrahigh-throughput exfoliation of graphite into pristine ‘single-layer’ graphene using microwaves and molecularly engineered ionic liquids[J]. Nat. Chem., 2015, 7: 730-736.
doi: 10.1038/nchem.2315 pmid: 26291945

[52] Matsumoto M, Shimizu S, Sotoike R, Watanabe M, Iwasa Y, Aida T. Exceptionally high electric double layer capacitances of oligomeric ionic liquids[J]. J. Am. Chem. Soc., 2017, 139(45): 16072-16075.
doi: 10.1021/jacs.7b09156 pmid: 29019662

[53] Vélez J F, Vázquez-Santos M B, Amarilla J M, Herradón B, Morales E. Geminal pyrrolidinium and piperidinium dicationic ionic liquid electrolytes. Synthesis, characterization and cell performance in LiMn2O4 rechargeable lithium cells[J]. J. Power Sources, 2019, 439: 227098.

[54] Zhang Z X, Zhou H Y, Yang L, Tachibana K, Kamijima K, Jian X. Asymmetrical dicationic ionic liquids based on both imidazolium and aliphatic ammonium as potential electrolyte additives applied to lithium secondary batteries[J]. Electrochim. Acta, 2008, 53(14): 4833-4838.

[55] Li S, Zhu M Y, Feng G. The effects of dication symmetry on ionic liquid electrolytes in supercapacitors[J]. J. Phys.: Condens. Matter., 2016, 28: 464005.

[56] Li S, Feng G, Cummings P T. Interfaces of dicationic ionic liquids and graphene: a molecular dynamics simulation study[J]. J. Phys. Condens. Matter, 2014, 26(28): 284106.

[57] Li S, Van Aken K L, McDonough J K, Feng G, Gogotsi Y, Cummings P T. The electrical double layer of dicationic ionic liquids at onion-like carbon surface[J]. J. Phys. Chem. C, 2014, 118: 3901-3909.

[58] Costa R, Pereira C M, Silva A F. Dicationic ionic liquid: Insight in the electrical double layer structure at mercury, glassy carbon and gold surfaces[J]. Electrochim. Acta, 2014, 116: 306-313.

[59] Li D D, Yang Y R, Wang X D, Feng G. Electrical double layer of linear tricationic ionic liquids at graphite electrode[J]. J. Phys. Chem. C, 2020, 124: 15723-15729.

[60] Lian C, Su H, Liu H, Wu J Z. Electrochemical behavior of nanoporous supercapacitors with oligomeric ionic liquids[J]. J. Phys. Chem. C, 2018, 122(26): 14402-14407.

[61] Yeganegi S, Soltanabadi A, Farmanzadeh D. Molecular dynamic simulation of dicationic ionic liquids: Effects of anions and alkyl chain length on liquid structure and diffusion[J]. J. Phys. Chem. B, 2012, 116(37): 11517-11526.

[62] Farmanzadeh D, Soltanabadi A, Yeganegi S. DFT study of the geometrical and electronic structures of geminal dicationic ionic liquids 1,3-bis

[3-methylimidazolium-1-yl] hexane halides[J]. J. Chin. Chem. Soc., 2013, 60(5): 551-558.

[63] Sedghamiz E, Khashei F, Moosavi M. Linear tricationic ionic liquids: Insights into the structural features using DFT and molecular dynamics simulation[J]. J. Mol. Liq., 2018, 271: 96-104.

[64] Lopes J N C, Padua A A H. Molecular force field for ionic liquids composed of triflate or bistriflylimide anions[J]. J. Phys. Chem. B, 2004, 108(43): 16893-16898.

[65] Li S, Feng G, Cummings P T. Interfaces of dicationic ionic liquids and graphene: A molecular dynamics simulation study[J]. J. Phys.: Condens. Matter, 2014, 26(28): 284106.

[66] Lopes J N C, Deschamps J, Padua A A H. Modeling ionic liquids using a systematic all-atom force field[J]. J. Phys. Chem. B, 2004, 108(6): 2038-2047.

[67] Sedghamiz E, Moosavi M. Tricationic ionic liquids: Str-uctural and dynamical properties via molecular dynamics simulations[J]. J. Phys. Chem. B, 2017, 121(8): 1877-1892.

[68] Torkzadeh M, Moosavi M. Heterogeneity in microstructures and dynamics of dicationic ionic liquids with symmetric and asymmetric cations-sciencedirect[J]. J. Mol. Liq., 2021, 330: 115632.

[69] Bodo E, Chiricotto M, Caminiti R. Structure of geminal imidazolium bis(trifluoromethylsulfonyl)imide dicationic ionic liquids: A theoretical study of the liquid phase[J]. J. Phys. Chem. B, 2011, 115(49): 14341-14347.

[70] Khakan H, Yeganegi S. Molecular dynamics simulations of amide functionalized imidazolium bis(trifluoromethan-esulfonyl)imide dicationic ionic liquids[J]. J. Phys. Chem. B, 2017, 121(31): 7455-7463.

[71] Prado C E R, Freitas L C G. Molecular dynamics simulation of the room-temperature ionic liquid 1-butyl-3-met-hylimidazolium tetrafluoroborate[J]. Theochem-J. Mol. Struct., 2007, 847(1-3): 93-100.

[72] Tariq M, Forte P A S, Costa Gomes M F, Canongia Lopes J N, Rebelo L P N. Densities and refractive indices of imidazolium and phosphonium based ionic liquids: Effect of temperature, alkyl chain length and anion[J]. J. Chem. Thermodyn., 2009, 41(6): 790-798.

[73] Mahapatra A, Chakraborty M, Barik S, Sarkar M. Comparison between pyrrolidinium-based and imidazolium-based dicationic ionic liquids: Intermolecular interaction, structural organization, and solute dynamics[J]. Phys. Chem. Chem. Phys., 2021, 23: 21029.
doi: 10.1039/d1cp02790e pmid: 34522923

[74] Moosavi M, Khashei F, Sharifi A, Mirzaei M. Transport properties of short alkyl chain length dicationic ionic liquids—the effects of alkyl chain length and temperature[J]. Ind. Eng. Chem. Res., 2016, 55(33): 9087-9099.

[75] Ishida T, Shirota H. Dicationic versus monocationic ionic liquids: Distinctive ionic dynamics and dynamical heterogeneity[J]. J. Phys. Chem. B, 2013, 117(4): 1136-1150.

[76] Chatterjee K, Pathak A D, Lakma A, Sharma C S, Singh A K. Synthesis, characterization and application of a non-flammable dicationic ionic liquid in lithium-ion battery as electrolyte additive[J]. Sci. Rep., 2020, 10(1): 9606.
doi: 10.1038/s41598-020-66341-x pmid: 32541876

[77] Vélez J F, Vazquez-Santos M B, Amarilla J M, Tartaj P, Morales E. Asymmetrical imidazolium-trialkylammonium room temperature dicationic ionic liquid electrolytes for Li-ion batteries[J]. Electrochim. Acta, 2018, 280: 171-180.

[78] Hossein H, Gildeh S F G, Ghauri K, Fathei P. Physicochemical properties of the imidazolium-based dicationic ionic liquids (DILs) composed of ethylene π-spacer by changing the anions: A quantum chemical approach[J]. Ionics, 2020, 26: 1963-1988.
doi: 10.1007/s11581-019-03325-6

[79] Yeganegi S, Sokhanvaran V, Soltanabadi A. Study of thermodynamic properties of imidazolium-based ionic liquids and investigation of the alkyl chain length effect by molecular dynamics simulation[J]. Mol. Simul., 2013, 39(13): 1070-1078.

[80] Li D D, Li E C, Yang Y R, Wang X D, Feng G. Structure and capacitance of electrical double layers in tricationic ionic liquids with organic solvents[J]. J. Phys. Chem. B, 2021, 125(46): 12753-12762.

[81] Sun H, Zhang D J, Liu C B, Zhang C Q. Geometrical and electronic structures of the dication and ion pair in the geminal dicationic ionic liquid 1,3-bis[3-methylimidazolium-yl]propane bromide[J]. Theochem-J. Mol. Struct., 2009, 900(1-3): 37-43.

[82] Alavi S M, Yeganegi S. Computational study of halogen-free boron based dicationic ionic liquids of [bis-mim][bmb]2 and [bis-mim][bscb]2[J]. Spectrochim. Acta, Part A, 2019, 210: 181-192.

[83] Li S, Feng G, Bañuelos J L, Rother G, Fulvio P F, Dai S, Cummings P T. Distinctive nanoscale organization of dicationic versus monocationic ionic liquids[J]. J. Phys. Chem. C, 2013, 117(35): 18251-18257.

[84] Li S, Bañuelos J L, Zhang P F, Feng G, Dai S, Rother G, Cummings P T. Toward understanding the structural heterogeneity and ion pair stability in dicationic ionic liquids[J]. Soft Matter, 2014, 10(45): 9193-9200.
doi: 10.1039/c4sm01742k pmid: 25328976

[85] Torkzadeh M, Moosavi M. Probing the effect of side alkyl chain length on the structural and dynamical micro-heterogeneities in dicationic ionic liquids[J]. J. Phys. Chem. B, 2020, 124(50): 11446-11462.

[86] Serva A, Migliorati V, Lapi A, Aquilanti G, Arcovito A, D’Angelo P. Structural properties of geminal dicationic ionic liquid/water mixtures: A theoretical and experimental insight[J]. Phys. Chem. Chem. Phys., 2016, 18(24): 16544-16554.
doi: 10.1039/c6cp01557c pmid: 27272477

[87] Bhargava B L, Klein M L. Nanoscale organization in aqueous dicationic ionic liquid solutions[J]. J. Phys. Chem. B, 2011, 115(35): 10439.

[88] Bhargava B L, Klein M L. Formation of interconnected aggregates in aqueous dicationic ionic liquid solutions[J]. J. Chem. Theory Comput., 2010, 6(3): 873.
doi: 10.1021/ct900674t pmid: 26613314

[89] Palchowdhury S, Bhargava B L. Effect of spacer chain length on the liquid structure of aqueous dicationic ionic liquid solutions: Molecular dynamics studies[J]. Phys. Chem. Chem. Phys., 2015, 17(17): 11627-11637.
doi: 10.1039/c5cp00873e pmid: 25865828

[90] Li S, Feng G, Cummings P T. The effects of dicationsymmetry on ionic liquid electrolytes in supercapacitors[J]. J. Phys.: Condens. Matter, 2016, 28: 464005.

[91] Li S, Zhang P, Pasquale F F, Patrick C H, Feng G, Dai S, Peter T C. Enhanced performance of dicationic ionic liquid electrolytes by organic solvents[J]. J. Phys. Condens. Matter, 2014, 26(28): 284105.

[92] Wagner R, Preschitschek N, Passerini S, Leker J, Winter M. Current research trends and prospects among the various materials and designs used in lithium-based batteries[J]. J. Appl. Electrochem., 2013, 43: 481-496.

[93] Vélez J F, Santos M B V, Amarilla J M, Herradón B, Morales E. Geminal pyrrolidinium and piperidinium dicationic ionic liquid electrolytes. Synthesis, characterization and cell performance in LiMn2O4 rechargeable lithium cells[J]. J. Power Sources, 2019, 439: 227098.

[94] Xiao D W, Dou Q Y, Zhang L, Ma Y L, Shi S Q, Lei S L, Yu H Y, Yan X B. Optimization of organic/water hybrid electrolytes for high-rate carbon-based supercapacitor[J]. Adv. Funct. Mater., 2019, 29(42): 1904136.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.