No abstract

Silicon−carbon (Si−C) hybrids have been proven to be the most promising anodes for the next-generation lithium-ion batteries (LIBs) due to their superior theoretical capacity (∼4200 mAh g −1 ). However, it is still a critical challenge to apply this material for commercial LIB anodes because of the large volume expansion of Si, unstable solid-state interphase (SEI) layers, and huge internal stresses upon lithiation/delithiation. Here, we propose an engineering concept of multiscale buffering, taking advantage of a nanosized Si−C nanowire architecture through fabricating specific microsized wool-ball frameworks to solve all the above-mentioned problems. These wool-ball-like frameworks, prepared at high yields, nearly matching industrial scales (they can be routinely produced at a rate of ∼300 g/h), are composed of Si/C nanowire building blocks. As anodes, the Si−C wool-ball frameworks show ultrastable Li + storage (2000 mAh g −1 for 1000 cycles), high initial Coulombic efficiency of ∼90%, and volumetric capacity of 1338 mAh cm −3 . In situ TEM proves that the multiscale buffering design enables a small volume variation, only ∼19.5%, reduces the inner stresses, and creates a very thin SEI. The perfect multiscale elastic buffering makes this material more stable compared to common Si nanoparticle-assembled counterpart electrodes.

Precise control of crystal orientations and macroscopic morphology of a perovskite crystal is crucial for various optoelectronic applications relying on charge carrier transport tuning along exposed crystal facets.

The practical application of Si‐based materials is widely impeded by poor electrochemical cycling stability. Here, inspired by the compact cladding and close connection structure of beans, an efficient buffering bean‐structured material of Si/C framework as a stable anode for Li‐ion storage is designed. By a simple ball‐milling process, the kilogram‐scale production of the Si/C can be realized. The Si/C composites exhibit excellent enhancement of electrochemical performance with a large storage capacity (1162.2 mAh g−1 at 0.1 C and 920.6 mAh g−1 at 0.2 C) and superior cycling stability (734 mAh g−1 after 200 cycles). The superior electrochemical performance is from the unique bean‐structured Si/C composites. Some micropores in porous carbon (PC) materials can offer void space that can alleviate stress and reduce volume expansion during the lithiation/delithiation process, and the PC can also act as a conductive matrix to enhance the conductivity and facilitate the diffusion of Li ions and electrons.