Synergizing Phase and Cavity in CoMoO_xS_y Yolk–Shell Anodes to Co‐Enhance Capacity and Rate Capability in Sodium Storage

Abstract

Sodium‐ion batteries (SIBs) have been recognized as the promising alternatives to lithium‐ion batteries for large‐scale applications owing to their abundant sodium resource. Currently, one significant challenge for SIBs is to explore feasible anodes with high specific capacity and reversible pulverization‐free Na+ insertion/extraction. Herein, a facile co‐engineering on polymorph phases and cavity structures is developed based on CoMo‐glycerate by scalable solvothermal sulfidation. The optimized strategy enables the construction of CoMoOxSy with synergized partially sulfidized amorphous phase and yolk–shell confined cavity. When developed as anodes for SIBs, such CoMoOxSy electrodes deliver a high reversible capacity of 479.4 mA h g−1 at 200 mA g−1 after 100 cycles and a high rate capacity of 435.2 mA h g−1 even at 2000 mA g−1, demonstrating superior capacity and rate capability. These are attributed to the unique dual merits of the anodes, that is, the elastic bountiful reaction pathways favored by the sulfidation‐induced amorphous phase and the sodiation/desodiation accommodatable space benefits from the yolk–shell cavity. Such yolk–shell nano‐battery materials are merited with co‐tunable phases and structures, facile scalable fabrication, and excellent capacity and rate capability in sodium storage. This provides an opportunity to develop advanced practical electrochemical sodium storage in the future.

Encapsulating Sb/MoS2 Into Carbon Nanofibers Via Electrospinning Towards Enhanced Sodium Storage

“…In the reversible anodic scan, the oxidation peak at 0.66–0.86 V is assigned to the multistep sodium extraction reaction and the electrochemical oxidation of Mo nanograins to MoS 2 [34] . Besides, it should be noted that the charge/discharge curves overlap well with conformal profiles in the consequent cycles, implying good electrochemical reversibility of the Sb@MoS 2 @C electrode.…”

In Situ Transformation of Metal Molybdates into Polymetallic Sulfides with Enriched Edge Sites for High-Performance Supercapacitors

“…For the Co 2p spectrum, the two fitting peaks at 780.6 eV for Co 2p 3/2 and 796.9 eV for Co 2p 1/2 were related to the characteristic Co 2+ (Figure C) . The fitting of the high-resolution Mo 3d spectrum exhibited the two peaks at 235.2 and 232.1 eV belonging to Mo 3d 3/2 and 3d 5/2 orbital electrons of Mo 6+ (Figure E), respectively. The high-resolution O 1s spectrum was deconvolved into two peaks at 531.2 and 530.0 eV (Figure D), which were separately assigned to −OH from absorbed H 2 O in the sample and lattice oxygen (Ni–O, Co–O, and Mo–O bonding).…”

“…The fitting S 2p spectrum exhibited two main peaks and one Sat. peak, where the two peaks at 162.8 and 161.7 eV belonging to S 2p 3/2 and 2p 1/2 were indexed to S 2– from the transition metal–sulfur bonds (Ni–S, Co–S, and Mo–S bonding) and surficial S 2– of NiCoMoS, − respectively. Especially, the Mo 4+ and Mo 5+ species were observed in the Mo 3d spectrum of NiCoMoS (Figure E), and the peak position of Mo 6+ shifted (0.8 eV) to a higher energy compared with that of the NiCoMoO 4 precursor.…”

Shell-confined atom and plasma: incidental degeneracy, metallic character and information entropy

“…Such an environment enhances stability and activity of noble-metal catalysts by inhibiting the sintering effect [48][49][50][51][52], amplifies photoluminescence in nano crystals by reducing non-radiative Auger processes [47,53] and removes defects in polymer crystals [54,55] etc. Apart from these examples, shell confinement has potential applications in pollution control [56,57], therapeutics [58] and energy storage [59][60][61].…”