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

• Published in: Advanced functional materials 2022-11, Vol.32 (48), p.n/a
• Main Authors: Ji, Mingze, Ni, Jie, Liang, Xing, Cheng, Qian, Gao, Guohua, Wu, Guangming, Xiao, Qiangfeng
• Format: Article
• Language: English
• Subjects: Biological activity; Biomimetics; carnivorous Utricularia; Concentration gradient; Damping; Encapsulation; Energy consumption; Energy storage; Lithium sulfur batteries; Materials science; Mechanical properties; Nanoparticles; Nanospheres; porous carbon; Scavenging; Shells (structural forms); Synthesis; vanadium oxide; yolk‐shell structures
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202206589

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 (≈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. VOx@C yolk‐shell nanospheres synthesized by biomimicking the prey‐predation process of Utricularia achieve transport of VOx nanoparticles into preformed hollow carbon spheres against a concentration gradient with continuous energy input via ultrasonication, thus achieving a high raw material utilization rate realized. The synthesized VOx@C effectively immobilizes and regenerates polysulfides by trapping and catalytically converting polysulfides during charging and discharging in LiS batteries.