Berlin 2024 – wissenschaftliches Programm

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AKE: Arbeitskreis Energie

AKE 2: Processes and Materials for Energy Technologies

AKE 2.4: Vortrag

Dienstag, 19. März 2024, 10:45–11:00, TC 006

Mn-substituted V₂C MXene as anode materials for Li-Ion batteries — •Tobias König¹, Peng Guo^{1, 2}, Tom Wickenhäuser¹, Lennart Singer¹, Peter Comba², and Rüdiger Klingeler¹ — ¹Kirchhoff Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, D-69120 Heidelberg, Germany — ²Anorganisch Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany

The recently found class of layered materials, MXenes, has attracted attention as potential anode materials in lithium-ion batteries due to their high theoretical capacity as well as their long cycling stability. We report on the effect of a Mn-substitution in V₂C MXenes, i.e. VMnC, synthesised by different etching processes. The distinct peaks in cyclic voltammetry measurements of VMnC suggest that Mn-ions offer extra redox-active centers yielding an increase of the specific capacity compared to V₂C. Galvanostatic cycling with potential limitation studies show significantly larger reversible capacities of 370 mAh/g in VMnC, at a current of 100 mA/g, which exceeds 256 mAh/g observed in V₂C by more than 40%. Additional investigations show the impact of different etching solvents applied during the synthesis process of the MXenes. In contrast to the abovementioned performance of VMnC synthesized using HCl+LiF as an etching solvent, the specific capacity amounts to only 260 mAh/g when using HCl+NaF. We discuss this result with respect to the interlayer distances and sample morphology. Overall, Mn-substitution strongly affects and improves the electrochemical performance of V₂C MXenes.

Keywords: LIB; Lithium-ion battery; anode materials; MXenes