Simon, P. & Gogotsi, Y. Perspectives for electrochemical capacitors and related devices. Nat. Mater. 19, 1151–1163 (2020).
Shao, H., Wu, Y.-C., Lin, Z., Taberna, P.-L. & Simon, P. Nanoporous carbon for electrochemical capacitive energy storage. Chem. Soc. Rev. 49, 3005–3039 (2020).
Wu, J. Understanding the electric double-layer structure, capacitance, and charging dynamics. Chem. Rev. 122, 10821–10859 (2022).
Choi, C. et al. Achieving high energy density and high power density with pseudocapacitive materials. Nat. Rev. Mater. 5, 5–19 (2020).
Fleischmann, S. et al. Pseudocapacitance: from fundamental understanding to high power energy storage materials. Chem. Rev. 120, 6738–6782 (2020).
Simon, P., Gogotsi, Y. & Dunn, B. Where do batteries end and supercapacitors begin? Science 343, 1210–1211 (2014).
Chmiola, J., Largeot, C., Taberna, P.-L., Simon, P. & Gogotsi, Y. Monolithic carbide-derived carbon films for micro-supercapacitors. Science 328, 480–483 (2010).
Lee, J. A. et al. Ultrafast charge and discharge biscrolled yarn supercapacitors for textiles and microdevices. Nat. Commun. 4, 1970 (2013).
Yu, Z., Tetard, L., Zhai, L. & Thomas, J. Supercapacitor electrode materials: nanostructures from 0 to 3 dimensions. Energy Environ. Mater. 8, 702–730 (2015).
Beidaghi, M. & Gogotsi, Y. Capacitive energy storage in micro-scale devices: recent advances in design and fabrication of micro-supercapacitors. Energy Environ. Mater. 7, 867–884 (2014).
Merlet, C. et al. On the molecular origin of supercapacitance in nanoporous carbon electrodes. Nat. Mater. 11, 306–310 (2012).
Xiao, J. et al. Electrolyte gating in graphene-based supercapacitors and its use for probing nanoconfined charging dynamics. Nat. Nanotechnol. 15, 683–689 (2020).
Wang, X. et al. Probing nanoconfined ion transport in electrified 2D laminate membranes with electrochemical impedance spectroscopy. Small Methods 6, e2200806 (2022).
Hoang Ngoc Minh, T., Stoltz, G. & Rotenberg, B. Frequency and field-dependent response of confined electrolytes from brownian dynamics simulations. J. Chem. Phys. 158, 104103 (2023).
Goikolea, E. & Mysyk, R. in Emerging Nanotechnologies in Rechargeable Energy Storage Systems 131–169 (2017).
Pal, B. et al. Understanding electrochemical capacitors with in situ techniques. Renew. Sustain. Energy Rev. 149, 111418 (2021).
Patra, A. et al. Understanding the charge storage mechanism of supercapacitors: in situ/operando spectroscopic approaches and theoretical investigations. J. Mater. Chem. A 9, 25852–25891 (2021).
Wang, L. X. et al. Tracking ion transport in nanochannels via transient single-particle imaging. Angew. Chem. Int. Ed. 135, e202315805 (2023).
Xin, W. et al. Tunable ion transport in two-dimensional nanofluidic channels. J. Phys. Chem. Lett. 14, 627–636 (2023).
Boyd, S. et al. Effects of interlayer confinement and hydration on capacitive charge storage in birnessite. Nat. Mater. 20, 1689–1694 (2021).
Guo, Y. et al. Sub-nanometer confined ions and solvent molecules intercalation capacitance in microslits of 2D materials. Small 17, e2104649 (2021).
Pean, C. et al. Confinement, desolvation, and electrosorption effects on the diffusion of ions in nanoporous carbon electrodes. J. Am. Chem. Soc. 137, 12627–12632 (2015).
Fleischmann, S. et al. Continuous transition from double-layer to Faradaic charge storage in confined electrolytes. Nat. Energy 7, 222–228 (2022).
Zhang, E. et al. Unraveling the capacitive charge storage mechanism of nitrogen-doped porous carbons by EQCM and ssNMR. J. Am. Chem. Soc. 144, 14217–14225 (2022).
Ge, K., Shao, H., Raymundo-Piñero, E., Taberna, P.-L. & Simon, P. Cation desolvation-induced capacitance enhancement in reduced graphene oxide (rGO). Nat. Commun. 15, 1935 (2024).
Liu, L., Raymundo-Pinero, E., Sunny, S., Taberna, P. L. & Simon, P. Role of surface terminations for charge storage of Ti3C2Tx MXene electrodes in aqueous acidic electrolyte. Angew. Chem. Int. Ed. 63, e202319238 (2024).
Liu, X. et al. Structural disorder determines capacitance in nanoporous carbons. Science 384, 321–325 (2024).
Yin, H., Shao, H., Daffos, B., Taberna, P.-L. & Simon, P. The effects of local graphitization on the charging mechanisms of microporous carbon supercapacitor electrodes. Electrochem. Commun. 137, 107258 (2022).
Forse, A. C., Merlet, C., Griffin, J. M. & Grey, C. P. New perspectives on the charging mechanisms of supercapacitors. J. Am. Chem. Soc. 138, 5731–5744 (2016).
Prehal, C. et al. Tracking the structural arrangement of ions in carbon supercapacitor nanopores using in situ small-angle X-ray scattering. Energy Environ. Mater. 8, 1725–1735 (2015).
Futamura, R. et al. Partial breaking of the coulombic ordering of ionic liquids confined in carbon nanopores. Nat. Mater. 16, 1225–1232 (2017).
Prehal, C. et al. Quantification of ion confinement and desolvation in nanoporous carbon supercapacitors with modelling and in situ X-ray scattering. Nat. Energy 2, 16215 (2017).
Mao, X. et al. Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces. Nat. Mater. 18, 1350–1357 (2019).
Lee, S. S., Koishi, A., Bourg, I. C. & Fenter, P. Ion correlations drive charge overscreening and heterogeneous nucleation at solid–aqueous electrolyte interfaces. Proc. Natl Acad. Sci. USA 118, e2105154118 (2021).
Tian, Y. et al. Nanoscale one-dimensional close packing of interfacial alkali ions driven by water-mediated attraction. Nat. Nanotechnol. 19, 479–484 (2024).
Gao, Q., Tsai, W. Y. & Balke, N. In situ and operando force-based atomic force microscopy for probing local functionality in energy storage materials. Electrochem. Sci. Adv. 2, e2100038 (2021).
Wang, H. et al. In situ NMR spectroscopy of supercapacitors: insight into the charge storage mechanism. J. Am. Chem. Soc. 135, 18968–18980 (2013).
Forse, A. C. et al. NMR study of ion dynamics and charge storage in ionic liquid supercapacitors. J. Am. Chem. Soc. 137, 7231–7242 (2015).
Liu, D. et al. Ion-specific nanoconfinement effect in multilayered graphene membranes: a combined nuclear magnetic resonance and computational study. Nano Lett. 23, 5555–5561 (2023).
Quill, T. J. et al. An ordered, self-assembled nanocomposite with efficient electronic and ionic transport. Nat. Mater. 22, 362–368 (2023).
Forse, A. C. et al. Direct observation of ion dynamics in supercapacitor electrodes using in situ diffusion NMR spectroscopy. Nat. Energy 2, 16216 (2017).
Chen, B. et al. Highly localized charges of confined electrical double layers inside 0.7 nm layered channels. Adv. Energy Mater. 13, 2300716 (2023).
Favaro, M. et al. Unravelling the electrochemical double layer by direct probing of the solid/liquid interface. Nat. Commun. 7, 12695 (2016).
Zaman, W. et al. In situ investigation of water on MXene interfaces. Proc. Natl Acad. Sci. USA 118, e2108325118 (2021).
Levi, M. D. et al. Electrochemical quartz crystal microbalance (EQCM) studies of ions and solvents insertion into highly porous activated carbons. J. Am. Chem. Soc. 132, 13220–13222 (2010).
Tsai, W.-Y., Taberna, P.-L. & Simon, P. Electrochemical quartz crystal microbalance (EQCM) study of ion dynamics in nanoporous carbons. J. Am. Chem. Soc. 136, 8722–8728 (2014).
Griffin, J. M. et al. In situ NMR and electrochemical quartz crystal microbalance techniques reveal the structure of the electrical double layer in supercapacitors. Nat. Mater. 14, 812–819 (2015).
Niu, L. et al. Understanding the charging of supercapacitors by electrochemical quartz crystal microbalance. Ind. Chem. Mater. 1, 175–187 (2023).
Levi, M. D., Daikhin, L., Aurbach, D. & Presser, V. Quartz crystal microbalance with dissipation monitoring (EQCM-D) for in-situ studies of electrodes for supercapacitors and batteries: a mini-review. Electrochem. Commun. 67, 16–21 (2016).
Sigalov, S., Levi, M. D., Daikhin, L., Salitra, G. & Aurbach, D. Electrochemical quartz crystal admittance studies of ion adsorption on nanoporous composite carbon electrodes in aprotic solutions. J. Solid State Electrochem. 18, 1335–1344 (2014).
Levi, M. D., Sigalov, S., Aurbach, D. & Daikhin, L. In situ electrochemical quartz crystal admittance methodology for tracking compositional and mechanical changes in porous carbon electrodes. J. Phys. Chem. C 117, 14876–14889 (2013).
Maurel, V. et al. Operando AC in-plane impedance spectroscopy of electrodes for energy storage systems. J. Electrochem. Soc. 169, 120510 (2022).
Marcotte, A., Mouterde, T., Nigues, A., Siria, A. & Bocquet, L. Mechanically activated ionic transport across single-digit carbon nanotubes. Nat. Mater. 19, 1057–1061 (2020).
Cheng, C. et al. Low-voltage electrostatic modulation of ion diffusion through layered graphene-based nanoporous membranes. Nat. Nanotechnol. 13, 685–690 (2018).
Gouy, M. On the constitution of the electric charge on the surface of an electrolyte. J. Phys. Theor. Appl. 9, 457–468 (1910).
Chapman, D. L. LI. A contribution to the theory of electrocapillarity. Lond. Edinb. Dublin Philos. Mag. J. Sci. 25, 475–481 (1913).
Stern, O. The theory of the electrolytic double-layer. Z. Elektrochem. 30, 1014–1020 (1924).
Frumkin, A., Petrii, O. & Damaskin, B. in Comprehensive Treatise of Electrochemistry: the Double Layer 221–289 (1980).
Trasatti, S. & Lust, E. in Modern Aspects of Electrochemistry Vol. 33 (eds White, R. A. et al.) 1–215 (Springer, 1999).
Wei, Z. et al. Relation between double layer structure, capacitance, and surface tension in electrowetting of graphene and aqueous electrolytes. J. Am. Chem. Soc. 146, 760–772 (2023).
Alam, M. T., Islam, M. M., Okajima, T. & Ohsaka, T. Measurements of differential capacitance at mercury/room-temperature ionic liquids interfaces. J. Phys. Chem. C 111, 18326–18333 (2007).
Lockett, V., Horne, M., Sedev, R., Rodopoulos, T. & Ralston, J. Differential capacitance of the double layer at the electrode/ionic liquids interface. Phys. Chem. Chem. Phys. 12, 12499–12512 (2010).
Ye, J. et al. Charge storage mechanisms of single-layer graphene in ionic liquid. J. Am. Chem. Soc. 141, 16559–16563 (2019).
Uematsu, Y., Netz, R. R. & Bonthuis, D. J. The effects of ion adsorption on the potential of zero charge and the differential capacitance of charged aqueous interfaces. J. Phys. Condens. Matter 30, 064002 (2018).
Huang, J. On obtaining double-layer capacitance and potential of zero charge from voltammetry. J. Electroanal. Chem. 870, 114243 (2020).
Xu, P., von Rueden, A. D., Schimmenti, R., Mavrikakis, M. & Suntivich, J. Optical method for quantifying the potential of zero charge at the platinum–water electrochemical interface. Nat. Mater. 22, 503–510 (2023).
Wang, Y., Gordon, E. & Ren, H. Mapping the potential of zero charge and electrocatalytic activity of metal–electrolyte interface via a grain-by-grain approach. Anal. Chem. 92, 2859–2865 (2020).
McCaffrey, D. L. et al. Mechanism of ion adsorption to aqueous interfaces: graphene/water vs. air/water. Proc. Natl Acad. Sci. USA 114, 13369–13373 (2017).
Gao, C. et al. Measuring the pseudocapacitive behavior of individual V2O5 particles by scanning electrochemical cell microscopy. Anal. Chem. 95, 10565–10571 (2023).
Ebejer, N. et al. Scanning electrochemical cell microscopy: a versatile technique for nanoscale electrochemistry and functional imaging. Annu. Rev. Anal. Chem. 6, 329–351 (2013).
Wang, X. et al. Titanium carbide MXene shows an electrochemical anomaly in water-in-salt electrolytes. ACS Nano 15, 15274–15284 (2021).
Bazant, M. Z., Storey, B. D. & Kornyshev, A. A. Double layer in ionic liquids: overscreening versus crowding. Phys. Rev. Lett. 106, 046102 (2011).
Wu, Y. C. et al. Electrochemical characterization of single layer graphene/electrolyte interface: effect of solvent on the interfacial capacitance. Angew. Chem. Int. Ed. 60, 13317–13322 (2021).
Chen, W. et al. Two-dimensional quantum-sheet films with sub-1.2 nm channels for ultrahigh-rate electrochemical capacitance. Nat. Nanotechnol. 17, 153–158 (2022).
Jaugstetter, M., Blanc, N., Kratz, M. & Tschulik, K. Electrochemistry under confinement. Chem. Soc. Rev. 51, 2491–2543 (2022).
Liu, Y. M., Merlet, C. & Smit, B. Carbons with regular pore geometry yield fundamental insights into supercapacitor charge storage. ACS Cent. Sci. 5, 1813–1823 (2019).
Merlet, C. et al. Highly confined ions store charge more efficiently in supercapacitors. Nat. Commun. 4, 2701 (2013).
Wang, B. et al. Interlayer confined water enabled pseudocapacitive sodium-ion storage in nonaqueous electrolyte. ACS Nano 18, 798–808 (2023).
Lounasvuori, M. et al. Vibrational signature of hydrated protons confined in MXene interlayers. Nat. Commun. 14, 1322 (2023).
Chmiola, J. et al. Anomalous increase in carbon capacitance at pore sizes less than 1 nanometer. Science 313, 1760–1763 (2006).
Baggio, B. F. & Grunder, Y. In situ X-ray techniques for electrochemical interfaces. Annu. Rev. Anal. Chem. 14, 87–107 (2021).
Chen, J. & Lee, P. S. Electrochemical supercapacitors: from mechanism understanding to multifunctional applications. Adv. Energy Mater. 11, 2003311 (2021).
Kondrat, S. & Kornyshev, A. Superionic state in double-layer capacitors with nanoporous electrodes. J. Phys. Condens. Matter 23, 022201 (2010).
Son, C. Y. & Wang, Z. G. Image-charge effects on ion adsorption near aqueous interfaces. Proc. Natl Acad. Sci. USA 118, e2020615118 (2021).
Kondrat, S., Feng, G., Bresme, F., Urbakh, M. & Kornyshev, A. A. Theory and simulations of ionic liquids in nanoconfinement. Chem. Rev. 123, 6668–6715 (2023).
Kondrat, S., Pérez, C., Presser, V., Gogotsi, Y. & Kornyshev, A. Effect of pore size and its dispersity on the energy storage in nanoporous supercapacitors. Energy Environ. Mater. 5, 6474–6479 (2012).
Luo, Z.-X., Xing, Y.-Z., Ling, Y.-C., Kleinhammes, A. & Wu, Y. Electroneutrality breakdown and specific ion effects in nanoconfined aqueous electrolytes observed by NMR. Nat. Commun. 6, 6358 (2015).
Hey, D. et al. Identifying and preventing degradation in flavin mononucleotide-based redox flow batteries via NMR and EPR spectroscopy. Nat. Commun. 14, 5207 (2023).
Forse, A. Nuclear Magnetic Resonance Studies of Ion Adsorption in Supercapacitor Electrodes. PhD thesis, Univ. Cambridge (2015).
Levy, A., de Souza, J. P. & Bazant, M. Z. Breakdown of electroneutrality in nanopores. J. Colloid Interface Sci. 579, 162–176 (2020).
Robin, P., Delahais, A., Bocquet, L. & Kavokine, N. Ion filling of a one-dimensional nanofluidic channel in the interaction confinement regime. J. Chem. Phys. 158, 124703 (2023).
Sugahara, A. et al. Negative dielectric constant of water confined in nanosheets. Nat. Commun. 10, 850 (2019).
Xu, T. et al. Discovery of fast and stable proton storage in bulk hexagonal molybdenum oxide. Nat. Commun. 14, 8360 (2023).
Mitchell, J. B., Wang, R., Ko, J. S., Long, J. W. & Augustyn, V. Critical role of structural water for enhanced Li+ insertion kinetics in crystalline tungsten oxides. J. Electrochem. Soc. 169, 030534 (2022).
Tang, P. et al. Understanding pseudocapacitance mechanisms by synchrotron X‐ray analytical techniques. Energy Environ. Mater. 6, e12619 (2023).
Levi, M. D., Salitra, G., Levy, N., Aurbach, D. & Maier, J. Application of a quartz-crystal microbalance to measure ionic fluxes in microporous carbons for energy storage. Nat. Mater. 8, 872–875 (2009).
Shpigel, N. et al. Can anions be inserted into MXene? J. Am. Chem. Soc. 143, 12552–12559 (2021).
Wei, J. et al. Metal-ion oligomerization inside electrified carbon micropores and its effect on capacitive charge storage. Adv. Mater. 34, e2107439 (2022).
Lu, C. et al. Dehydration-enhanced ion–pore interactions dominate anion transport and selectivity in nanochannels. Sci. Adv. 9, eadf8412 (2023).
Lin, Z., Shao, H., Xu, K., Taberna, P.-L. & Simon, P. MXenes as high-rate electrodes for energy storage. Trends Chem. 2, 654–664 (2020).
Tsai, W.-Y., Wang, R., Boyd, S., Augustyn, V. & Balke, N. Probing local electrochemistry via mechanical cyclic voltammetry curves. Nano Energy 81, 105592 (2021).
Zheng, K., Xian, Y. & Lin, Z. A method for deconvoluting and quantifying the real‐time species fluxes and ionic currents using in situ electrochemical quartz crystal microbalance. Adv. Mater. Interfaces 9, 2200112 (2022).
Michael, H., Jervis, R., Brett, D. J. L. & Shearing, P. R. Developments in dilatometry for characterisation of electrochemical devices. Batteries Supercaps 4, 1378–1396 (2021).
Hu, M. et al. High-capacitance mechanism for Ti3C2Tx MXene by in situ electrochemical Raman spectroscopy investigation. ACS Nano 10, 11344–11350 (2016).
Ferrari, A. C. & Basko, D. M. Raman spectroscopy as a versatile tool for studying the properties of graphene. Nat. Nanotechnol. 8, 235–246 (2013).
Yan, J., Zhang, Y., Kim, P. & Pinczuk, A. Electric field effect tuning of electron–phonon coupling in graphene. Phys. Rev. Lett. 98, 166802 (2007).
Gittins, J. W. et al. Understanding electrolyte ion size effects on the performance of conducting metal–organic framework supercapacitors. J. Am. Chem. Soc. 146, 12473–12484 (2024).
Escobar-Teran, F. et al. Gravimetric and dynamic deconvolution of global EQCM response of carbon nanotube based electrodes by AC-electrogravimetry. Electrochem. Commun. 70, 73–77 (2016).
Frąckowiak, E., Płatek-Mielczarek, A., Piwek, J. & Fic, K. Advanced characterization techniques for electrochemical capacitors. Adv. Inorg. Chem. 79, 151–207 (2022).
Eleri, O. E., Lou, F. & Yu, Z. in Nanostructured Materials for Supercapacitors 101–128 (2022).
Wang, S. et al. Electrochemical impedance spectroscopy. Nat. Rev. Methods Prim. 1, 41 (2021).
Tivony, R., Safran, S., Pincus, P., Silbert, G. & Klein, J. Charging dynamics of an individual nanopore. Nat. Commun. 9, 4203 (2018).
Black, J. M. et al. Strain‐based in situ study of anion and cation insertion into porous carbon electrodes with different pore sizes. Adv. Energy Mater. 4, 1300683 (2014).
Ge, K., Shao, H., Taberna, P.-L. & Simon, P. Understanding ion charging dynamics in nanoporous carbons for electrochemical double layer capacitor applications. ACS Energy Lett. 8, 2738–2745 (2023).
Henrique, F., Żuk, P. J. & Gupta, A. A network model to predict ionic transport in porous materials. Proc. Natl Acad. Sci. USA 121, e2401656121 (2024).
Zhan, H. et al. Physics-based machine learning discovered nanocircuitry for nonlinear ion transport in nanoporous electrodes. J. Phys. Chem. C 127, 13699–13705 (2023).
Zhou, H. et al. General design concepts for CAPodes as ionologic devices. Angew. Chem. 135, e202305397 (2023).
