Open Access Research Article Issue
Pomegranate-type Si/C anode with SiC taped, well-dispersed tiny Si particles for lithium-ion batteries
Journal of Advanced Ceramics 2021, 10 (5): 1129-1139
Published: 13 July 2021
Abstract PDF (14.4 MB) Collect

Severe volume expansion and inherently poor lithium ion transmission are two major problems of silicon anodes. To address these issues, we proposed a pomegranate-type Si/C composite anode with highly dispersed tiny silicon particles as the core assisted by small amount of SiC. Skillfully exploiting the high heat from magnesiothermic reduction, SiC can assist the good dispersion of silicon and provide good interface compatibility and chemical stability. The silicon anchored to the carbon shell provides multipoint contact mode, that together with the carbon shell frame, significantly promoting the transfer of dual charge. Besides, the pomegranate-type microcluster structure also improves the tap density of the electrode, reduces the direct contact area between active material and electrolyte, and enhances the electrochemical performance.

Open Access Research Article Issue
Role of in-situ formed free carbon on electromagnetic absorption properties of polymer-derived SiC ceramics
Journal of Advanced Ceramics 2020, 9 (5): 617-628
Published: 10 October 2020
Abstract PDF (8.5 MB) Collect

In order to enhance dielectric properties of polymer-derived SiC ceramics, a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane (AHPCS) and divinyl benzene (DVB) to form carbon-rich SiC. As expected, the free carbon contents of resultant SiC ceramics annealed at 1600 ℃ are significantly enhanced from 6.62 wt% to 44.67 wt%. After annealing at 900-1600 ℃, the obtained carbon-rich SiC ceramics undergo phase separation from amorphous to crystalline feature where superfine SiC nanocrystals and turbostratic carbon networks are dispersed in an amorphous SiC(O) matrix. The dielectric properties and electromagnetic (EM) absorption performance of as-synthesized carbon-rich SiC ceramics are significantly improved by increasing the structural order and content of free carbon. For the 1600 ℃ ceramics mixed with paraffin wax, the minimum reflection coefficient (RCmin) reaches -56.8 dB at 15.2 GHz with the thickness of 1.51 mm and a relatively broad effective bandwidth (the bandwidth of RC values lower than -10 dB) of 4.43 GHz, indicating the excellent EM absorption performance. The carbon-rich SiC ceramics have to be considered as harsh environmental EM absorbers with excellent chemical stability, high temperature, and oxidation and corrosion resistance.

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