Covalent surface modification of bifunctional two-dimensional metal carbide MXenes as sulfur hosts for sodium–sulfur batteries

Abstract

Room temperature sodium-sulfur (RT Na-S) batteries show extraordinary potential in large-scale energy storage. MXenes have been demonstrated to be promising sulfur hosts for Na-S batteries, and their surface functional groups...

N-Functionalized Ti2C MXene as a High-Performance Adsorbent for Strontium Ions: A First-Principles Study

“…In order to obtain the most stable conformations of N-, O-, F-, and OH-functionalized Ti 2 C, the energies of all their conformations were calculated as shown in Table S1. The most stable structures (the lowest energy structure) of Ti 2 CO 2 , Ti 2 CF 2 , and Ti 2 C­(OH) 2 were observed in configuration I, while Ti 2 CN 2 preferred configuration III, which is consistent with previous research. − We find that the terminal functional group type of Ti 2 C can significantly affect its structural characteristics. The obtained lattice constants for Ti 2 CN 2 , Ti 2 CO 2 , Ti 2 CF 2 , and Ti 2 C­(OH) 2 were 3.210, 3.018, 3.036, and 3.052 Å, and their corresponding thicknesses were 3.776, 4.439, 4.795, and 6.791 Å, respectively.…”

Synergistically boosting the anchoring effect and catalytic activity of MXenes as bifunctional electrocatalysts for sodium–sulfur batteries by single-atom catalyst engineering

“…In addition, the incorporation of TMs also strengthens the adsorption of NaPSs on the Ti 2 CS 2 substrate. The binding energies of soluble Na 2 S 8 (2.54–2.99 eV), Na 2 S 6 (2.80–3.29 eV), and Na 2 S 4 (3.18–3.85 eV) on these four TM@Ti 2 CS 2 catalysts are dramatically larger than that on DOL and DME (0.50–0.65 eV), 64 manifesting that these four TM@Ti 2 CS 2 -based sulfur hosts can effectively suppress the shuttle effect in Na–S batteries. Moreover, all four TM@Ti 2 CS 2 catalysts exhibit increasingly stronger affinity toward NaPSs with increased sodiation, and the binding energies of Na 2 S on them are the largest.…”

Ultrahigh areal capacity and long cycling stability of sodium metal anodes boosted using a 3D-printed sodiophilic MXene/rGO microlattice aerogel

“…Recently, MXenes have been reported to enhance the cycling stability of sodium metal anodes by improving the sodium metal deposition behavior. 18,25,26 Among the MXene family, Ti 3 C 2 T x has gained significant popularity owing to its high electrical conductivity, large interlayer spacing and low Na + diffusion barrier. Furthermore, the surface of Ti 3 C 2 T x is functionalized with various groups (such as -F, -O) during the HF etching process, which makes Ti 3 C 2 T x sodiophilic to guide Na uniform deposition.…”

“…Furthermore, the surface of Ti 3 C 2 T x is functionalized with various groups (such as -F, -O) during the HF etching process, which makes Ti 3 C 2 T x sodiophilic to guide Na uniform deposition. [26][27][28][29][30] Owing to these advantages, Ti 3 C 2 T x has been investigated as a stable host for sodium metal anodes. 31,32 For example, Fang et al emphasized the role of -F and -O functional groups in promoting Na deposition by evaluating the adsorption energies of F-Na and O-Na.…”