| Rus |  |
Eng |  |
Strain-Based In Situ Study of Anion and Cation Insertion into Porous Carbon Electrodes with Different Pore Sizes
Jennifer M. Black1,Guang Feng2,*,Pasquale F. Fulvio3,Patrick C. Hillesheim3,Sheng Dai3,4,Yury Gogotsi5,Peter T. Cummings2,Sergei V. Kalinin1,Nina Balke1,*
1 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
2 Chemical & Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
3 Chemical Sciences Division Oak Ridge National Laboratory, Oak Ridge, TN, USA
4 Department of Chemistry University of Tennessee, Knoxville, TN, USA
5 Department of Materials Science and Engineering and A. J. Drexel Nanotechnology Institute Drexel University, Philadelphia, PA, USA
Article first published online: 8 OCT 2013, Adv. Energy Mater.,DOI: 10.1002/aenm.201300683
Keywords: electrochemical capacitors; atomic force microscopy; molecular dynamics; ionic liquids
Abstract
Atomic force microscopy is used to monitor the expansion of porous carbon electrodes, which results from insertion/adsorption of ions in carbon pores during charging. The strain data collected at various potential scan rates are used to obtain information on anion and cation kinetics. Molecular dynamics simulations are performed to determine the molecular origins of charge-induced expansion in porous carbons.
The expansion of porous carbon electrodes in a room temperature ionic liquid (RTIL) is studied using in situ atomic force microscopy (AFM). The effect of carbon surface area and pore size/pore size distribution on the observed strain profile and ion kinetics is examined. Additionally, the influence of the potential scan rate on the strain response is investigated. By analyzing the strain data at various potential scan rates, information on ion kinetics in the different carbon materials is obtained. Molecular dynamics (MD) simulations are performed to compare with and provide molecular insights into the experimental results; this is the first MD work investigating the pressure exerted on porous electrodes under applied potential in a RTIL electrolyte. Using MD, the pressure exerted on the pore wall is calculated as a function of potential/charge for both a micropore (1.2 nm) and a mesopore (7.0 nm). The shape of the calculated pressure profile matches closely with the strain profiles observed experimentally.
Supporting Information
N2 adsorption measurements were performed to determine the surface area and pore size distribution s of the carbon membranes used in this study. Figure S1 a and b show the N2 adsorption isotherms as well as the calculated pore size distributions (PSDs) for the MC, MC - A, and MC - G membranes. These are type IV isotherms with H1 hysteresis loops characteristic of materials with large mesopores. [1]
The steepness of the capillary condensation step results from the uniform diameter of the main mesopores and consequently narrow pore size distribution, which i s usually reported for ordered and disordered soft - templated carbon materials. The surface area of the MC, MC - A, and MC - G carbons w ere determined to be 579, 798, and 282 m 2 g - 1 , respectively. Mechanical indentation experiments were also performed to dete rmine the hardness of the carbon membranes, and results are shown in Figure S1c. From the indentation experiments the Young’s modulus for the MC, MC - A, and MC - G w ere determined to be 6.783, 4.586, and 9.655 GPa, respectively.
To compare the strain behavior of a non-porous carbon with the porous carbons used in this study, the charge induced expansion of a non-porous glassy carbon electrode was also measured using in-situ AFM.
Figure S2 shows the relative height change of MC membrane and glassy carbon over three cyclic voltammogram cycles performed at 1 mV s-1. The MC membrane experiences an expansion of ca. 0.15% with the maximum occurring at the most positive and most negative applied potentials. For the glassy carbon electrode the maximum strain observed was very small (<0.001 %), and was unrelated to the potential applied to the electrode. The absence of strain observed in the non-porous glassy carbon provides further support that the expansion experienced in porous carbon materials is related to the ion insertion/adsorption in the carbon pores.
References: [1] X. Q. Wang, Q. Zhu, S. M. Mahurin, C. D. Liang, S. Dai, Carbon, 2010, 48, 557
MXenes potential applications include sensors, wound healing materials, and drug delivery systems. A recent study explored how different synthesis methods affect the safety and performance of MXenes. By comparing etching conditions and intercalation strategies, researchers discovered that fine-tuning the surface chemistry of MXenes plays a crucial role in improving biocompatibility. These results provide practical guidelines for developing safer MXenes and bring the field one step closer to real biomedical applications.
Exellent news, our joint patent application with Drexel University on highly porous MAX phase precursor for MXene synthesis published. Congratulations and thanks to all team involved!
Last Call! Have you submitted your abstract for IEEE NAP-2025 yet? Join us at the International Symposium on "The MXene Frontier: Transformative Nanomaterials Shaping the Future" – the largest MXene-focused conference in Europe this year! Final Submission Deadline: May 15, 2025. Don’t miss this exclusive opportunity to showcase your research and engage with world leaders in the MXene field!
We are excited to announce the publication of latest review article on MXenes in Healthcare. This comprehensive review explores the groundbreaking role of MXenes—an emerging class of 2D materials—in revolutionizing the fields of medical diagnostics and therapeutics. Read the full article here: https://doi.org/10.1039/D4NR04853A.
Congratulations and thank you to our collaborators from TU Wien and CEST for very interesting work and making it published! In this work, an upscalable electrochemical MXene synthesis is presented. Yields of up to 60% electrochemical MXene (EC-MXene) with no byproducts from a single exfoliation cycle are achieved.
Congratulations to all collaborators with this interesting joint work!
Thank you to our collaborators for the amazing joint work recently published in Graphene and 2D Nanomaterials about MXene–silk fibroin composite films aiming to develop materials with tunable electronic and thermal properties
Dr. Oleksiy Gogotsi, director of MRC and Carbon-Ukraine, innovative companies that are among the leaders on the world MXene market, visited 2024 MRS Fall Meeting & Exhibit. together with Dr. Maksym Pogorielov, Head of Advanced Biomaterials and Biophysics Laboratory, University of Latvia.
MRC and Carbon-Ukraine team visited the 3rd International MXene conference held at Drexel University on August 5-8, 2024. Conference brought together the best reserchers and leading experts on MXene field. 
Together with colleagues from the University of Latvia, MRC/Carbone Ukraine, Adam Mickiewicz University, University Clinic Essen, and others, we have developed a novel concept involving the binding of antibodies to MXenes. In our research, we utilized anti-CEACAM1 antibodies to develop targeted photo-thermal therapy for melanoma (in vitro), paving the way for future in vivo studies and clinical trials. For the first time, we demonstrate the feasibility of delivering MXenes specifically targeted to melanoma cells, enabling the effective ablation of cancer cells under near-infrared (NIR) light. This new technique opens up vast potential for the application of MXenes in cancer treatment, diagnostics, drug delivery, and many other medical purposes.
