Role of Surface Structure on Li-ion Energy Storage Capacity of Two-dimensional Transition Metal Carbides
Abstract
A combination of density functional theory (DFT) calculations and experiments are used to shed light on the relation between surface structure and Li-ion storage capacities of the following functionalized two-dimensional (2D) transition metal carbides, or MXenes: Sc2C, Ti2C, Ti3C2, V2C, Cr2C, and Nb2C. The Li-ion storage capacities are found to strongly depend on the nature of the surface functional groups, with O groups exhibiting the highest theoretical Li-ion storage capacities. MXene surfaces can be initially covered with OH groups, removable by high temperature treatment or by reactions in the first lithiation cycle. This was verified by annealing f-Nb2C and f-Ti3C2 at 673 K and 773 K in vacuum for 40 h and in situ x-ray adsorption spectroscopy (XAS) and Li capacity measurements for the first lithiation/delithiation cycle of f-Ti3C2. The high temperature removal of water and OH was confirmed using x-ray diffraction and inelastic neutron scattering. The voltage profile and x-ray adsorption near edge structure of f-Ti3C2 revealed surface reactions in the first lithiation cycle.
Moreover, lithiated oxygen terminated MXenes surfaces are able to adsorb additional Li beyond a monolayer, providing a mechanism to substantially increase capacity, as observed mainly in delaminated MXenes and confirmed by DFT calculations and XAS. The calculated Li diffusion barriers are low, indicative of the measured high-rate performance. We predict Cr2C to possess high Li capacity due to the low activation energy of water formation at high temperature, while Sc2C is predicted to potentially display low Li capacity due to increased reaction barriers for OH removal.
Source: www.pubs.acs.org
Here we demonstrate a new developed method for depositing Ti3C2Tx MXenes onto hydrophobic electrospun PCL membranes using oxygen plasma treatment. These novel patches hold tremendous potential for providing mechanical support to damaged heart tissue and enabling electrical signal transmission,thereby mimicking the crucial electroconductivity required for normal cardiac function. After a detailed investigation of scaffold-to-cell interplay, including electrical stimulation, novel technology has the potential for clinical application not only for cardiac regeneration, but also as neural and muscular tissue substitutes.
MX-MAP project participants from MRC Dr. Oleksiy Gogotsi and Veronika Zahorodna performed split secondment visit to project partner organization University of Padova (Italy). MX-MAP project works on development of the key strategies for MXene medical applications. 
CanbioSe Project Meeting and Project Workshop was held at European Institute of Membranes (IEM), University of Montpellier, France on September 26-27, 2023. The workshop was focused on the theme of "Commercializing Biosensors, Intellectual Property, and Knowledge Transfer from Academia to Industry.
Dr. Oleksiy Gogotsi and Veronika Zahorodna visited IEEE NAP 2023 conference held in Bratislava on September 10-15, 2023. The prime focus of the IEEE NAP-2023 was on nanoscale materials with emphasis on interdisciplinary research exploring and exploiting their unique physical and chemical proprieties for practical applications.
Director of MRC and Carbon-Ukraine Dr. Oleksiy Gogotsi visited CEST labs in Wiener Neustadt (Low Energy Ion Scattering, Batteries development) and TU Vienna (ELSA, SFA). He meet with Dr. Pierluigi Bilotto, Dr. Chriatian Pichler and their colleagues, discussing novel materials and r&d activities for new technologies.
MX-MAP Session was held during the YUCOMAT Conference 2023 titled: "Towards MXenes’ biomedical applications by high-dimensional immune MAPping", HORIZON-MSCA-2021-SE-01 project MX-MAP.
CANBIOSE project participants from MRC Dr. Oleksiy Gogotsi and Veronika Zahorodna performed secondment visit to project partner organization European Institute of Membranes in Montpellier (France) on August -September 2023.
MRC researchers Dr. Oleksiy Gogotsi and Veronika Zahorodna were visiting Nanobiomedical Centre, Adam Mickewicz University in Poznan, Poland due to close collaboration with AMU team led by Dr. Igor Iatsunskiy. 
Meeting during the MXene international conference held in Drexel University on Aug. 3, 2022, and discussing the roadmap for launching MX-MAP research project on MXenes for medical applications.