Preparation of hollow SnO2@N-C nanospheres for high performance lithium-ion battery

Abstract

• Hollow tin dioxide nanospheres coated with an N -doped carbon layer were developed. • It involves a sacrificial template method and a subsequent carbon coating process. • Hollow SnO 2 @N-C nanospheres exhibit high stable capacity and high rate performance. • Superior performance is due to the hollow structure and N -doped carbon coating. Hollow micro/nanostructures have attracted considerable interest for lithium storage because of their merits in alleviating volume expansion. This paper presents novel preparation method for hollow tin dioxide nanospheres coated with an ultrathin N -doped carbon layer (SnO 2 @N-C) using MgSn(OH) 6 nanospheres as sacrificial templates through the alkali etching, annealing, acid washing, polydopamine coating, and subsequent carbonization. The resulting hollow SnO 2 @N-C nanosphere anode exhibited good cycling stability (1154.2 mAh g −1 after 200 cycles at 0.2 A g −1 ) and good rate performance (791.8, 708.6, 595.9, 402.2, 234.1, and 80.7 mA h g −1 at 0.1, 0.2, 0.5 1, 2, and 5 A g −1 , respectively). In addition, a capacity of 734.2 mAh g −1 was obtained as the current density was back to 0.1 A g −1 . The superior electrochemical performance was ascribed to their hollow microstructure and ultrathin N -doped carbon coating.