Scalable Synthesis of Pore-Rich Si/C@C Core-Shell-Structured Microspheres for Practical Long-Life Lithium-Ion Battery Anodes.

Silicon/carbon (Si/C) composites have rightfully earned the attention as anode candidates for high-energy-density lithium-ion batteries (LIBs) owing to their advantageous capacity and superior cycling stability, yet their practical application remains a significant challenge. In this study, we report the large-scale synthesis of an intriguing micro/nanostructured pore-rich Si/C microsphere consisting of Si nanoparticles tightly immobilized onto a micron-sized cross-linked C matrix that is coated by a thin C layer (denoted P-Si/C@C) using a low-cost spray-drying approach and a chemical vapor deposition process with inorganic salts as pore-forming agents. The as-obtained P-Si/C@C composite has high porosity that provides sufficient inner voids to alleviate the huge volume expansion of Si.

Scalable synthesis of ant-nest-like bulk porous silicon for high-performance lithium-ion battery anodes.

Although silicon is a promising anode material for lithium-ion batteries, scalable synthesis of silicon anodes with good cyclability and low electrode swelling remains a significant challenge. Herein, we report a scalable top-down technique to produce ant-nest-like porous silicon from magnesium-silicon alloy. The ant-nest-like porous silicon comprising three-dimensional interconnected silicon nanoligaments and bicontinuous nanopores can prevent pulverization and accommodate volume expansion during cycling resulting in negligible particle-level outward expansion.

Mechanisms of Metal-Free Aerobic Oxidation To Prepare Benzoxazole Catalyzed by Cyanide: A Direct Cyclization or Stepwise Oxidative Dehydrogenation and Cyclization?

The detailed mechanism of the cyanide-catalyzed synthesis of benzoxazole from 2-aminophenol and benzaldehyde was investigated in depth using density functional theory (DFT). The metal-free aerobic oxidative process as well as the dehydrogenation detail were examined and described. Cyanide anion was proved to assist the oxygen atoms to undergo an aerobic dehydrogenation rather than direct cyclization which was predicted according to Baldwin's 5-exotet rule.