Interfacial engineering of graphene aerogel encapsulated FeSe2-Fe2O3 heterojunction nanotubes for enhanced lithium storage

Abstract

Heterointerface engineering has been proved to be an effective strategy to improve the electrochemical performances of electrode materials by overcoming inherent drawbacks of single phase electrode. However, the rational construction of heterogeneous composite with abundant heterogeneous interfaces for lithium-ion batteries (LIBs) remains a great challenge. Herein, graphene aerogel encapsulated FeSe2-Fe2O3 heterojunction nanotubes (FeSe2-Fe2O3@GA) with inner-outer bi-interfacial structures were fabricated by freeze-drying method and partial selenization treatment. The built-in electric fields induced on the FeSe2-Fe2O3 could greatly lower the activation energy for rapid charge transfer kinetics. And GA as outer surface not only could maintain the integrity of active material structure, but also enhance its electronic conductivity. Benefiting from these advantages, the FeSe2-Fe2O3@GA anode exhibits an improved electrochemical performance in term of lithium storage capacity (1515.6 mAh g−1 at 0.2 A g−1), cycle stability and high rate capability (492.7 mAh g−1 after 600 cycles at 1 A g−1). The kinetics analysis and theoretical calculation also interpret the significant role of heterointerface engineering construction in improving the reaction kinetics of lithium storage.