Solid state electrochemically synthesised β-SiC nanowires as the anode material in lithium ion batteries

초록

SiC was synthesised by electro-deoxidation of a SiO2/graphite mixture in a CaCl2 melt at 1173 K, and the reduced product was characterised by XRD, SEM-EDX, XPS and TEM-STEM. The SiC prepared had a powdery morphology, existed exclusively in the beta-phase, and possessed a unique nanostructure with nanowires of 400-600 nm in length and 10-40 nm in diameter. Cyclic voltammetric studies demonstrated that the nanowire SiC was electroactive towards Li+ ions. Battery tests yielded a specific capacity on the order of 1000 mAh/g at a charge-discharge rate of 0.5 A/g and a coulombic efficiency of more than 99% over hundreds of cycles. Being facile, affordable and scalable, the electrochemical synthesis method may be the missing link in making nano-SiC available for battery as well as other large-scale technologies. Some further improvement of the coulombic efficiency of the material made would however be necessary before its application in a practical cell can be considered.

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