Mo2TiC2 and Mo2Ti2C3 MXene Nanosheets as Electrode Materials for Sodium and Potassium Ion Batteries
Since last decade, lithium-ion batteries (LIB) have been intensively employed in applications such as powering of electronic portable devices and electric cars. Nevertheless, concerns regarding limited availability of lithium on the Earth’s crust have led researchers to look for alternative battery chemistries beyond those based on lithium compounds, namely, sodium and potassium ions – monovalent-ions that possess advantages such as low cost due to their abundant availability. Nonetheless, there are challenges associated with the development of sodium and potassium-based batteries due to the lack of suitable electrode materials and limited understanding of charge storage mechanisms in those that must be overcome. Concerning potential electrode materials for non-lithium alkali metal-ion batteries, research efforts have mainly focused on identifying new compositions that offer high electrochemical activity and cycling stability and developing techniques for production in large quantities in a cost-effective manner. In this regard, two-dimensional (2D) materials are desired electrode materials due the existence of inexhaustible active sites, which may lead to higher theoretical capacity. Under the 2D materials umbrella, graphene is the most known species; however, it is a 2D material made from a single element (carbon), whose current functionalization processes may result in the loss of some of graphene unique properties. On the other hand, transition metal dichalcogenides (TMDs) are also layered materials with more 40 species known; thus, yielding in a plethora of chemistries. However, exfoliation of these materials still present issues with respect to scalability, restacking and aggregation of the exfoliated nanosheets, for example. As one of the latest 2D materials discovered, transition metal carbides, carbonitrides and nitrides (MXenes) have been gaining traction. MXenes are layered materials with generalized formula is Mn+1XnTx , where M is a transition metal, X is a carbon and/or a nitrogen atom, and Tx a surface termination, for instance, chlorine, fluorine, hydroxyl, or oxygen. As a fast-growing family of 2D materials, since 2011 more than 30 MXene species were reported; therefore, offering a variety of chemistries, electrical and mechanical properties. Here we study two MXene species, namely Mo2TiC2 and Mo2Ti2C3 as anode materials for sodium (SIB) and potassium-ion batteries (KIB). Results indicate reasonable cycling stability under galvanostatic charge-discharge (GCD) of both MXenes as SIB and KIB, tested at 40 mA g-1. In addition, after 50 GCD cycles, KIB cells show higher specific charge capacity than SIB cells, evidence that the charge storage mechanism goes beyond the Na+ and K+ ion radii. Electrochemical impedance (EIS) studies are also presented, which provide a quantitative analysis of the impedance data to further understand processes taking place on the electrode system. To summarize, this is an initial study towards the understanding of 2D molybdenum-based MXene species (Mo2TiC2 and Mo2Ti2C3) as SIB and KIB, which comprises data with respect to capacity contribution from MXenes species, chemistry taking place for first and second cycles of GCD, charge storage mechanism, and EIS resistance values on the 50th cycle for sodium- and potassium-ion cells. Results show the stability, low equivalent series resistance, and potential of these Mxenes to be employed as active materials or conducting agents for the future of SIB and KIB.
Mo2TiC2 and Mo2Ti2C3 MXene Nanosheets as Electrode Materials for Sodium and Potassium Ion Batteries
Category
Poster Presentation
Description
Session: 16-01-01 National Science Foundation Posters - On Demand
ASME Paper Number: IMECE2020-25005
Session Start Time: ,
Presenting Author: Davi Marcelo Soares
Presenting Author Bio: Davi Marcelo Soares holds a Master of Science from University of Campinas (Unicamp), Brazil, and currently is a PhD student in Mechanical and Nuclear Engineering department at Kansas State University, advised by Dr. Gurpreet Singh. His research is in layered materials for electrochemical energy storage.
Authors: Davi Marcelo Soares Kansas State University
Christopher Shuck Drexel University
Narendra Kurra Drexel University
Yury Gogotsi Drexel University
Gurpreet SinghKansas State University