One‐Pot Synthesis of Antimony‐Embedded Silicon Oxycarbide Materials for High‐Performance Sodium‐Ion Batteries

Abstract

Sodium-ion batteries have recently attracted intensive attention due to their natural abundance and low cost. Antimony is a desirable candidate for an anode material for sodium-ion batteries due to its high theoretical capacity (660 mA h g −1 ). However, the utilization of alloy-based anodes is still limited by their inherent huge volume changes and sluggish kinetics. The Sbembedded silicon oxycarbide (SiOC) composites are simply synthesized via a one-pot pyrolysis process at 900 °C without any additives or surfactants, taking advantage of the superior self-dispersion properties of antimony acetate powders in silicone oil. The structural and morphological characterizations confirm that Sb nanoparticles are homogeneously embedded into the amorphous SiOC matrix. The composite materials exhibit an initial desodiation capacity of around 510 mA h g −1 and maintained an excellent capacity retention above 97% after 250 cycles. The rate capability test reveals that the composites deliver capacity greater than 453 mA h g −1 , even at the high current density of 20 C rate, owing to the free-carbon domain of SiOC material. The electrochemical and postmortem analyses confirm that the SiOC matrix with a uniform distribution of Sb nanoparticles provides the mechanical strength without degradation in conductive characteristics, suppressing the agglomeration of Sb particles during the electrochemical reaction.

A facile control in free‐carbon domain with divinylbenzene for the high‐rate‐performing Sb/SiOCcomposite anode material in sodium‐ion batteries

“…Silicone oil is cheaper and eco-friendly with a simpler synthesis process, compared with the polysiloxane-based precursor. [42][43][44] Previous studies also confirm that the phenyl-containing components in silicone oil precursor provide a higher electric conductivity of the final SiOC materials by forming a free-carbon region into the SiOC matrix. However, the amount of free-carbon domain is fixed and limited by the contents of the intrinsic phenyl-related sources in the silicone oil precursors, and this may restrict the diverse utilization of SiOC materials in battery applications.…”

Rational Design of Sb@C@TiO2 Triple‐Shell Nanoboxes for High‐Performance Sodium‐Ion Batteries

“…Among them, metallic Sb is regarded as one of the most promising anode materials for SIBs because of its high theoretical capacity of around 660 mAh g −1 (corresponding to Na 3 Sb) and appropriate redox potential (0.5-0.8 V vs Na/Na + ). [38] Nevertheless, the large volume variations (about 290%) during sodiation/desodiation process is the "Achilles' heel" of Sb-based anode materials, as these variations cause the continuous pulverization of the active material, damage the solid-electrolyte interface (SEI), and degrade the electric contact between Sb and the current collector. All of these effects rapidly deteriorate the capacity and cyclability of the electrode.…”

A Nanostructured Si/SiOC Composite Anode with Volume‐Change‐Buffering Microstructure for Lithium‐Ion Batteries

“…The morphology of the Si/SiOC composite was found to be strongly dependent on the amount of Si NPs, and we identified a critical PhTMS/Si weight ratio of 5:0.4, above and below which the microstructures of the Si/SiOC composites were different. In region 1 (weight ratio < 5:0.4), the as‐synthesized Si/SiOC composites still showed a bulk structure owing to the thermoplastic properties of PPSQ spheres, which tended to aggregate to form a dense structure with Si NPs entrapped in a continuous SiOC phase . When the PhTMS/Si weight ratio exceeded 5:0.4 (region 2), a granular structure comprising Si and SiOC NPs was obtained, and no distinct difference was observed with increasing amount of Si NPs.…”

“…In region 1( weight ratio < 5:0.4), the as-synthesized Si/SiOC composites still showed ab ulk structure owing to the thermoplastic properties of PPSQ spheres,w hich tended to aggregate to form ad ense structure with Si NPs entrapped in ac ontinuous SiOC phase. [7][8][9] When the PhTMS/Si weightr atio exceeded 5:0.4 (region 2), ag ranular structure comprising Si and SiOC NPs was obtained, and no distinct difference was observed with increasing amounto fS iN Ps. Both Si/SiOC-0.6 and Si/ SiOC-0.8 showed as tructure of stacked NPs interspersedb y pores (Figure 1f and Figure S3 a).…”