Prediction of Mobility, Enhanced Storage Capacity, and Volume Change during Sodiation on Interlayer-Expanded Functionalized Ti₃C₂ MXene Anode Materials for Sodium-Ion Batteries

Abstract

Sodium storage capacity, mobility, and volume change during sodiation on the surfaces of interlayer-expanded Ti3C2 MXenes are investigated using ab initio density functional theory. The theoretical results reveal that the interlayer-expanded bare, F-, O-, and OH-functionalized Ti3C2 MXenes exhibit low barriers for sodium diffusion and small changes of lattice constant during sodiation. In addition, enlarged interlayer distance enables the stable multilayer adsorption on the bare and O-functionalized Ti3C2 MXenes and therefore significantly enhances their theoretical capacities. Both bare and O-functionalized Ti3C2 MXenes are predicted to be prospective anode materials for sodium-ion batteries with high theoretical capacities, fast discharge/charge rates, and good cycling performances. The present results provide a new route to improve the battery performances of anode materials based on MXene intercalation hosts.

Ab initio prediction of borophene as an extraordinary anode material exhibiting ultrafast directional sodium diffusion for sodium-based batteries

“…In this work, we comprehensively investigated the feasibility of employing borophene as anode material for sodiumbased batteries using density functional theory (DFT) method. The calculation results show that borophene can not only provide a superhigh capacity (1,218 mAh g -1 ), but also exhibit a directional ultrahigh sodium diffusivity, which is estimated to be more than a thousand times higher than that of conventional anode materials such as Na 2 Ti 3 O 7 [26] and Na 3 Sb [27] and one to seven magnitudes higher than other previously reported 2D materials [12][13][14][15][16][17][18][19]. The ultrahigh diffusivity will revolutionize the rate capability of sodium-based batteries.…”

“…The loose packing between the 2D layers can accommodate the volume expansion caused by the insertion of sodium atoms and maintain the structural integrity. Many 2D materials, such as defective/doped graphene [12,13], transition metal dichalcogenides (TMD) [14,15], transition metal carbides (MXenes) [16,17] and phosphorene [18,19], have been explored as potential candidates for the anode material of sodium-based batteries using first-principle method, and some of the predicted good performance have already been proven in experiments [20,21]. Recently, borophene, a 2D sheet of boron, has been successfully synthesized by Mannix et al [22].…”

Atomic Sulfur Covalently Engineered Interlayers of Ti3C2 MXene for Ultra‐Fast Sodium‐Ion Storage by Enhanced Pseudocapacitance

“…In the previous works, multilayered MXenes used as the electrodes for Na‐ion storage exhibited unsatisfactory electrochemical performance due to the relatively narrow interlayer space for Na + intercalation, storage and diffusion. Previously density functional theory (DFT) calculation predicted that enlarged interlayer space of MXene (always refer to multilayered MXene unless otherwise stated) could enable the stable multilayer adsorption of Na + and thus significantly enhance the theoretical capacity . Experimentally, the increase of interlayer spacing of MXene achieved by the insertion of intercalating agents (such as ions, polymers, nanocarbons, and metal oxide nanoparticles …”

Emerging nanostructured electrode materials for water electrolysis and rechargeable beyond Li-ion batteries

“…However, graphene containing hybrids of TMDCs, TMOs, and MXenes are thoroughly discussed here. Computational studies predict that beyond graphene 2D materials can demonstrate advanced electrode characteristics [93][94][95][96][97][98][99][100][101][102][103], but in this review, we focus on experimental research and strategies that proved to be successful to improve performance of 2D materials in BLI batteries.…”

“…Most research aimed at understanding performance of MXene phases in BLI batteries is carried out by computational scientists [96][97][98][99][100][101][102], and experimental characterization, focused on Na-ion batteries, has emerged only in recent years. Ti 3 C 2 and Ti 2 C are two of the most studied MXene phases because of their well-established synthesis process and high electrochemical performance.…”