Graphene aerogel encapsulated Fe-Co oxide nanocubes derived from Prussian blue analogue as integrated anode with enhanced Li-ion storage properties

Abstract

Hybridizing metal oxides with three-dimensional graphene is highly desirable for improving the ability of lithium storage. Herein a general strategy was employed to fabricate nanocomposites containing heterometallic oxide and graphene aerogel (GA) for the first time, in which Prussian blue analogue (PBA) was selected as self-sacrificial template for the preparation of metal oxide. The Fe-Co oxide nanocubes in the composite were homogeneously encapsulated in the network of GA, and meanwhile acted spacers separating adjacent graphene sheets. The as-prepared self-standing Fe-Co oxide@GA composite was used directly as excellent integrated anode material of lithium-ion batteries. More importantly, the composite electrode delivered an outstanding cycle stability with a specific capacity of 947 mA h g−1 at 100 mA g−1 after 130 cycles. Such superior Li-ion storage ability originates from the hierarchically encapsulated architecture and the strong synergistic effect between metal oxide and GA. The interconnected network of GA significantly improves the conductivity of the whole electrode as well as provides the space for buffering volume change of metal oxides, whereas metal oxides strongly wrapped within graphene nanosheets contribute large specific capacity.