An alumina stabilized graphene oxide wrapped SnO2 hollow sphere LIB anode with improved lithium storage

Abstract

SnO₂ hollow spheres were stabilized by graphene oxide wrapping, by alumina coating deposited via atomic layer deposition (ALD), or the combination of the two methods and used in lithium ion battery anodes. We found that graphene oxide wrapping provides a better buffering of volume changes and results in reduced electrode pulverization and better preservation of the electrode morphology compared to bare SnO₂ hollow spheres. On the other hand, ALD coating provides a significant improvement in the rate performance of the anodes, and it could also improve the adhesion of the metal oxide to the conductive additive since the coating is applied to the entire electrode. The combination of the two techniques results in anodes with superior cycling and rate performance, with specific capacity of 1176 mA h g⁻¹ after 60 cycles at 0.1 A g⁻¹ (compared to 115 mA h g⁻¹ for bare hollow SnO₂ nanospheres) and specific capacity of 329 mA h g⁻¹ at 2 A g⁻¹ charge/discharge rate (compared to 7 mA h g⁻¹ for bare SnO₂ hollow spheres). The improvement in the performance was attributed to the superior preservation of anode morphology after cycling.