SnO2/Sn particles anchored in moderately exfoliated graphite as the anode of lithium-ion battery

Abstract

SnO2-based materials have been widely studied because of their high theoretical specific capacity, whereas the significant capacity fading is caused by the low reversibility conversion reaction and volume expansion. In this work, we proposed a precipitation-polymerization-thermal treatment method to construct SnO2-based composites by precipitation reaction of SnCl2 with moderately exfoliated graphite (MEG), subsequent dopamine (DA) polymerization and thermal treatment to fulfill nitrogen-doped-carbon (NC) coating and part transformation of SnO2 to Sn. Finally, we can obtain the SnO2/Sn/MEG@NC composites for high-performance lithium-ion batteries (LIBs). The conductive NC coating and MEG matrix have the function in facilitating electron transportation, restraining aggregation, and adapting to volume change of SnO2/Sn particles. Micron-sized Sn is broken during the cycles and forms nano-sized distribution with ultrafine SnO2, the hybrid SnO2/Sn allows highly effective reversibility conversion and alloying/de-alloying reactions upon cycles. As a result, the SnO2/Sn/MEG@NC electrode exhibits outstanding cycling stability (837.2 mAh g−1 at 1 A g−1 after 800 cycles), displaying outstanding performance for being LIBs.