Ultrafine Sb Pillared Few-Layered Ti₃C₂T_x MXenes for Advanced Sodium Storage

Abstract

Pillaring technology has proven to be an effective strategy to improve the electrochemical performance of MXenebased composites, especially the rate performance due to the enlarged interlayer spacing. Taking the larger radius of sodium ions into account, it is urgent to develop pillared MXene-based composites for sodium-ion batteries (SIBs). To fully deliver high rate performance of pillared MXenes and high capacity of Sb in SIBs, in this work, we exquisitely decorate ultrafine Sb particles onto flexible few-layered Ti 3 C 2 T x (f-Ti 3 C 2 T x ) nanosheets to fabricate Sb pillared Ti 3 C 2 T x (Sb/p-Ti 3 C 2 T x ) composites through facile electrostatic adsorption followed by the annealing process. Benefiting from the enhanced kinetics properties by highly conductive pillared f-Ti 3 C 2 T x and ultrafine Sb nanoparticles, the composites exhibit a reversible charge capacity of 438.1 mAh g −1 at 50 mA g −1 and a high retention rate of 126.6 mAh g −1 at 2 A g −1 . Furthermore, the strong interaction between Sb and Ti 3 C 2 T x via Ti−O−Sb chemical bonding endows the composites with high structural stability, leading to good cycling sustainability. More importantly, for the first time, we succeed in integrating dual advantages of the few-layered state of MXenes and pillaring technology in MXene-based composites for SIBs. This work supplies an effective modification strategy to conquer the drawbacks of Sb anodes and achieve exploitation of pillared few-layered MXene composites in SIBs, promoting the commercial process of MXenes in SIBs.

Faceted Antimony Particles with Interiors Reinforced with Reduced Graphene Oxide as High-Performance Anode Material for Sodium-Ion Batteries

“…The potential profile, current peak and the associated potentials (vs Na/Na + ) in the first sodiation half cycle are also likely to be partly influenced by the formation of SEI layer, although that seems to have been minimized here, because of the presence of fairly coarse electrode-active (Sb) particles (and, hence, low electrode/electrolyte interfacial area). The above aspects seem to be in agreement with other previous reports, − where SEI formation occurs in the very first sodiation half cycle at a relatively higher potential, with respect to that corresponding to the initiation of sodiation of Sb, followed by the conversion of metallic Sb to Na 3 Sb at lower potentials. Based on the literature related to sodiation/desodiation pathway(s) of Sb, − Sb/oxide composites − and the observations made here (with the CVs and chronopotentiograms), it is likely that during desodiation Na 3 Sb gets converted first to Na 1.7 Sb and then to cSb, along with some amorphous phase(s), such as aSb or aNa 1.0 Sb.…”

“…The above aspects seem to be in agreement with other previous reports, − where SEI formation occurs in the very first sodiation half cycle at a relatively higher potential, with respect to that corresponding to the initiation of sodiation of Sb, followed by the conversion of metallic Sb to Na 3 Sb at lower potentials. Based on the literature related to sodiation/desodiation pathway(s) of Sb, − Sb/oxide composites − and the observations made here (with the CVs and chronopotentiograms), it is likely that during desodiation Na 3 Sb gets converted first to Na 1.7 Sb and then to cSb, along with some amorphous phase(s), such as aSb or aNa 1.0 Sb. Accordingly, the second and subsequent sodiation half cycles also involved sodiation of some aSb, in addition to cSb.…”

Understanding the tunable sodium storage performance in pillared MXenes: a first-principles study

“…27 However, when they are used as an anode electrode material for rechargeable batteries, MXene nanosheets usually suffer from aggregation and the self-restacking effect during the cycling process, which affects the ion transport properties, leading to lowered capacities, rate capabilities and cycling stabilities. 28,29 Recently, an effective strategy has been proposed to overcome this shortcoming by fabricating pillared MXene structures with enlarged interlayer spacing. Lu et al found that the intercalation of Al ions in a two-dimensional Ti 3 C 2 T x anode increased the spacing of the MXene layers by about 0.1 nm, and the lithium storage capacity and cycling stability of the MXene anode were also significantly improved.…”

Element‐Doped Mxenes: Mechanism, Synthesis, and Applications

“…), [31] supercapacitors, [32] electrocatalyst, [33] photocatalyst, [34] field-effect transistor, [35] electromagnetic shielding, [36] seawater desalination [37] and other fields have broad application prospects.However, the disadvantages of MXenes, such as low flexibility, easy stacking, and poor stability in oxygen environment, greatly limit the further development of pristine MXenes. [38,39] In recent years, inspired by the elemental doping mechanism of graphene, [40][41][42] optimizing pristine MXene properties (such as electronic, optical, magnetic, etc.) by elemental doping methods has been shown to be an effective strategy.…”

“…However, the disadvantages of MXenes, such as low flexibility, easy stacking, and poor stability in oxygen environment, greatly limit the further development of pristine MXenes. [38,39] In recent years, inspired by the elemental doping mechanism of graphene, [40][41][42] optimizing pristine MXene properties (such as electronic, optical, magnetic, etc.) by elemental doping methods has been shown to be an effective strategy.…”