Controlled scalable synthesis of yolk‐shell antimony with porous carbon anode for superior Na‐ion storage

Abstract

Antimony (Sb) anodes explored for high energy density sodium cells are prone to rapid capacity decay during (de)alloying owing to reversible phase transformation (Sb⇌Na3Sb) induced volume expansion necessitates rationale materials and electrode design. Herein, we design a yolk‐shell structure where surfactant‐stabilized and pH modulated Sb nanoparticles (SbNPs) are carefully coated with Stöber silica and resorcinol‐formaldehyde resin at room temperature. Upon pyrolysis under argon followed by careful etching of the intermediate layer from Sb@SiO2@C double core‐shell leads to the formation of Sb@void@C yolk‐shell possessing SbNPs confined within mesoporous conductive carbon shells with sufficient void space allowing Sb to realize its full potential and display superior sodium storage behavior. Moreover, binder‐free electrodes fabricated by electrophoretic deposition deliver superior performance in a sodium cell with improved rate capability. A full cell fabricated with Prussian blue type NaxFe[Fe(CN)6] cathode paired with Sb@void@PC anode delivers a practical energy density of ∼142 Whkg–1 operating at ∼1.95 V. The favorable results of yolk‐shell Sb@void@C anodes in sodium‐ion battery demonstrate the structural superiority for future energy storage applications

Hexagonal Sb Nanocrystals as High-Capacity and Long-Cycle Anode Materials for Sodium-Ion Batteries

“…As indicated, the stripe distances of 0.31, 0.22, and 0.21 nm represent the lattice faces of Sb (012), Sb (104), and Sb (110), respectively. 41,42 The result is also consistent with the XRD patterns. More importantly, all the stripes are highly parallel, indicating the unexceptionable degree of crystallinity of the synthesized Sb nanocrystals with regular hexagonal morphologies.…”

“…In the HRTEM images shown in Figure e–g, the ordered parallel stripes with varied spacing distances are clearly distinguishable, which belong to different crystalline planes of Sb. As indicated, the stripe distances of 0.31, 0.22, and 0.21 nm represent the lattice faces of Sb (012), Sb (104), and Sb (110), respectively. , The result is also consistent with the XRD patterns. More importantly, all the stripes are highly parallel, indicating the unexceptionable degree of crystallinity of the synthesized Sb nanocrystals with regular hexagonal morphologies.…”

The energy storage application of core-/yolk–shell structures in sodium batteries

“…The inner core or yolk material is generally consisting of different metal or metal oxide, non-metal oxide, metal sulfide, phosphide, selenide, bimetallic etc. 27,38,43,75 Furthermore, porosity could be introduced into the material by different template etching method. Core-shell is consisting of core/sacrificial shell/outer shell structure.…”