Carbon-coated silicon nanowire array films for high-performance lithium-ion battery anodes

Carbon-coated silicon nanowire array films prepared by metal catalytic etching of silicon wafers and pyrolyzing of carbon aerogel were used for lithium-ion battery anodes. The films exhibited an excellent first discharge capacity of 3344 mAh g^-1 with a Coulombic efficiency of 84% at a rate of 150 mA g^-1 between 2 and 0.02 V and a significantly enhanced cycling performance, i.e., a reversible capacity of 1326 mAh g^-1 was retained after 40 cycles. These improvements were attributed to the uniform and continuous carbon coatings, which increased electronic contact and conduction and buffered large volume changes during lithium ion insertion/extraction.