3D porous carbon network-reinforced defective CoFeOx@C as a high-rate electrode for lithium-ion batteries

Abstract

Integrating metal oxides with three-dimensional (3D) porous carbon is extremely desirable for improving the capacity and cyclability of lithium-ion batteries (LIBs). Herein 3D porous carbon network (3DPCN)-reinforced composite electrodes were developed by integrating biomass (i.e., agaric)-derived 3DPCN and Prussian blue analogue (PBA)-generated carbon-coated metal oxides (CoFeOx@C). To achieve an integrated structure, PBA precursors were directly deposited and grown on 3DPCN (PBA/3DPCN), and then, PBA/3DPCN was subjected to low-temperature oxidation in air and thermal treatment in Ar to yield double carbon-modified metal oxides (CoFeOx@C/C). The interconnected CoFeOx@C/C electrode, as an advanced anode of LIBs, delivers excellent capacity and cyclability, with typical specific capacities of 1043.4 mAh g−1 at 0.2 A g−1 and 483.2 mAh g−1 at as high as 5.0 A g−1 after 120 cycles. This superior electrochemical performance originates from the interconnected structure of 3DPCN, the finely regulated composition of nanosized CoFeOx@C, and the tight contact and synergistic effect between 3DPCN and CoFeOx@C. The 3DPCN not only provides a void space for buffering the volume change of CoFeOx@C but also acts as a framework for improving the conductivity of the entire electrode, while compositionally optimized defective CoFeOx@C contributes the majority of the specific capacity. Our work paves the way to overcome the drawbacks (e.g., low electronic conductivity, self-aggregation, and low rate capability) of metal oxides as electrodes of LIBs.