Biomimetic Synthesis of VOx@C Yolk-Shell Nanospheres and Their Application in Li-S Batteries

Many biological processes involve active transport where the desired substances can be transported against the concentration gradient with energy consumption. This feature is highly desirable for the synthesis of yolk-shell structures using preformed capsules to efficiently encapsulate yolk materials. Here, the synthesis of VOx@C yolk-shell nanospheres by biomimicking prey-predation of carnivorous Utricularia is reported. The high intrinsic frequency and superior mechanical properties of hollow mesoporous carbon spheres (HMCS) maintain their integrity during ultrasonication, making HMCS an ideal capsule. Numerical simulation elucidates that the encapsulation of the VOx nanoparticles is ascribed to the periodic change of pressure and the damping force generated from the relative motion between the mesoporous tunnel in the HMCS and VOx nanoparticles. The resulting VOx@C yolk-shell nanospheres demonstrate promising application as a regenerative polysulfide-scavenging layer (RSL) for high-loading Li-S batteries (approximate to 5 mAh cm(-2)). As compared with the cells with a commercial Celgard polypropylene (PP) separator, those with a RSL present improved capacity retention from 467 to 860 mAh g(-1) after 100 cycles, superior rate capability, and reduced impedance. This method provides an additional synthesis tool for yolk-shell materials otherwise inaccessible by conventional methods with potential applications in energy storage and conversion devices.

Automated summary

This study reports the synthesis of VOx@C yolk-shell nanospheres using biomimicking prey-predation and demonstrates their potential application as a regenerative polysulfide-scavenging layer for high-loading Li-S batteries.