Indirect growth of mesoporous Bi@C core-shell nanowires for enhanced lithium-ion storage

In this paper, we propose a facile synthetic strategy for uniform bismuth@carbon (Bi@C) core-shell nanowires, which are prepared via controlled pyrolysis of Bi2S3@ glucose-derived carbon-rich polysaccharide (GCP) nanowires under an inert atmosphere. Carbonization of GCP and pyrolysis of Bi2S3 into Bi occur at 500 degrees C and 600 degrees C, respectively, which increase the specific surface area and the pore volume of the nanowires, thus allowing accommodation of more lithium ions. Meanwhile, the carbon shell serves as a buffer layer to relieve large volume expansion-contraction during the electrochemical alloy formation, and can also efficiently reduce the aggregation of the nanowires. As a proof-of-concept, the Bi@C core-shell nanowire anodes manifest enhanced cycling stability (408 mA h g(-1) after 100 cycles at a current density of 100 mA g(-1)) and rate capacity (240 mA h g(-1) at a current density of 1 A g(-1)), much higher than pure bismuth microparticles and corresponding Bi2S3@C nanowires.