In-situ synthesis of amorphous FeO(OH) coated ultrafine SnO2 on the surface of CNT as anode for lithium ion batteries

Abstract Robust SnO2-based anode materials for lithium ion batteries (LIBs) are currently suffering from extremely large volume changes which may lead to quick capacity decay in the cycling process. Recent researches indicate that amorphous materials can improve the cycling performances of LIBs, inspiring us to create amorphous coatings as accommodations for the stress caused by volume expansion. Here, a hydrothermal amorphous FeO(OH) coated ultrafine SnO2 nanocrystals on carbon nanotubes (CNTs) anode materials for LIBs are prepared from the precursor of H2SnO3@Fe(OH)3 fabricated by a double hydrolysis reaction. Due to the disorder of the atomic arrangement of amorphous state, the FeO(OH) coatings have excellent elasticity, which can buffer the volume expansion of SnO2 nanoparticles as well as themselves. Moreover, the amorphous coatings together with CNTs conductive networks can also suppress the agglomeration of SnO2 nanoparticles during the cycling process. The flexible amorphous coatings, well dispersed and ultrafine active particles, as well as highly conductive networks in the constructed architecture endows this novel anode materials a good long-cycle stability and rate performance, so that a high specific capacity of 400 mAh g-1 can be retained at 2 C (1.44 A g-1) after 500 cycles.