Incorporation of amorphous TiO2 into one-dimensional SnO2 nanostructures as superior anodes for lithium-ion batteries

Abstract Lithium-ion batteries (LIBs) with higher energy density are necessary to meet the increasing demands of energy storage system (ESS) in near future. Tin (IV) oxide, SnO 2 , is one of highly promising anode candidates due to its high theoretical capacity (782 mAh g −1 ), abundance, environmental friendliness, and safety with organic electrolytes. However, a rapid capacity fading and poor rate capabilities arising from the large volume expansion and subsequent agglomeration of Sn nanoparticles have been major issues of SnO 2 . Here, we have synthesized one-dimensional (1D) SnO 2 -amorphous titanium (IV) oxide NTs (SnO 2 -a-TiO 2 NTs), which allow both facile ionic and electron transport as well as easy penetration of electrolytes. The resultant SnO 2 -a-TiO 2 NTs not only alleviate volume expansion by maintaining their structural integrity but also possess minimal charge transfer resistance even after a number of cycles. SnO 2 -a-TiO 2 NTs exhibit both excellent cycle retention characteristics (1050.2 mAh g −1 after 250 cycles) and outstanding rate capability (522.3 mAh g −1 at a current density of 5000 mA g −1 ), which is attributed to the introduction of amorphous TiO 2 that not only acts as buffer agent for volume changes of SnO 2 but also allows fast surface-controlled diffusion process due to its pseudocapacitive charge storage mechanisms.