Heterostructured δ-MnO2/Fe2O3 nanoarrays layer-by-layer assembled on stainless-steel mesh as free-standing anodes for lithium ion batteries towards enhanced performance

Abstract

Heterostructured δ-MnO2/Fe2O3 nanoarrays layer-by-layer assembled on stainless-steel mesh was fabricated via a two-step hydrothermal synthesis. Compared to the corresponding individual phases such as δ-MnO2@SSM and Fe2O3@SSM, δ-MnO2/Fe2O3@SSM delivers a high initial discharge capacity of 1821 mAh g−1, and retain 1464 mAh g−1 after 200 cycles at 200 mA g−1, moreover, about 1135 mAh g−1 can still be achieved at 2.0 A g−1 after 500 cycles, demonstrating excellent long-term cycling performance. Furthermore, the composite demonstrates superior rate capability as well, about 503 mAh g−1 can be remained at a high current density of up to 10 A g−1. Besides a comprehensive contribution from electroactive δ-MnO2 and Fe2O3, the significantly enhanced performance is attributed to the unique porous structure and the heterointerfaces that would induce more active sites and improve electronic conductivity. This research reveals that δ-MnO2/Fe2O3@SSM is a promising anode material for advanced LIBs with high energy density and high power density.