Volker Presser
Title: Electrochemical desalination with MXene: where do we stand and where do we go from here?
First and last name: Volker Presser
Affiliation: INM – Leibniz Institute for New Materials & Saarland University (UdS), Saarbrücken, Germany
Short Biography:
Since 2015: Program Division Leader (INM) and Full Professor (UdS)
2013-2015: Junior Professor (UdS, Saarbrücken, Germany)
2012-2015: Junior Research Group Leader (INM, Saarbrücken, Germany)
2010-2012: Humboldt Fellow & Research Assistant Professor (Drexel University, USA)
2009: Dr. rer. nat. (Eberhard Karls Universität Tübingen, Germany)
Abstract:
Capacitive deionization (CDI) accomplishes energy-efficient water desalination by electrosorption of ions at the interface between saline solutions and porous carbon electrodes.[1] The process of ion electrosorption yields salt adsorption capacities of typically 15-20 mg/g (mg salt per g of the electrode) have been reported. The use of carbon limits the maximum achievable charge storage capacity and restricts the applicability of CDI to very low salt concentrations (typically below 20-50 mM). This issue originates from unfavorable co-ion expulsion from carbon nanopores concurrently occurring during counter-ion adsorption. Only once all co-ions have become depleted in the pores, permselective ion removal is accomplished. To transfer CDI from a niche technology to a more largescale use, new electrode materials and cell concepts need to be explored.
The use of Faradaic electrode materials has had a transformative impact on the research field for electrochemical water desalination.[2] The presentation will summarize key aspects of the implementation of ion intercalation materials for the deionization of aqueous media with ion concentration levels typical brackish water and seawater. We demonstrate the facile use of pseudocapacitive materials to effectively remove cations and anions from saline media. Transition metal carbides (MXene) are ideal candidates for this task per their ability to afford permselective ion intercalation even at high molar strength.[3] With enhanced ion mobility and lowered energetic barriers, there is even an improved desalination performance when increasing the salt concentration from low (10 mM) to high levels (1 M). Careful design of the MXene electrodes and operation within the electrochemical window enables performance stability. Also, the permselectivity of MXene can be used to enable the direct of of nanoporous carbon as the counter-electrode even for seawater desalination.[4]
But where do we go from here? MXene hybridized or nanomixed with other materials brings forth a highly enhanced desalination performance and finely tunes MXenes allow for selective ion extraction. The presentation will cover such emerging MXene-enabled applications at the water/energy research nexus.
[1] M. E. Suss, S. Porada, X. Sun, P. M. Biesheuvel, J. Yoon and V. Presser, Energy & Environmental Science 2015, 8, 2296-2319.
[2] P. Srimuk, X. Su, J. Yoon, D. Aurbach and V. Presser, Nature Reviews Materials 2020, 5, 517-538.
[3] a) P. Srimuk, J. Halim, J. Lee, Q. Tao, J. Rosen and V. Presser, ACS Sustainable Chemistry & Engineering 2018, 6, 3739-3747; b) P. Srimuk, F. Kaasik, B. Krüner, A. Tolosa, S. Fleischmann, N. Jäckel, M. C. Tekeli, M. Aslan, M. E. Suss and V. Presser, Journal of Materials Chemistry A 2016, 4, 18265-18271.
[4] M. Torkamanzadeh, L. Wang, Y. Zhang, Ö. Budak, P. Srimuk and V. Presser, ACS Applied Materials & Interfaces 2020, 12, 26013-26025.