Porous biscuit-like nanoplate FeNb11O29-x@C for lithium-ion storage and oxygen evolution.

ABSTRACT

The development of efficient and stable electrode materials for lithium-ion batteries (LIBs) and the oxygen evolution reaction (OER) is critical for clean and sustainable energy storage and conversion. In this work, porous biscuit-like nanoplate FeNb11O29-x@C is reasonably prepared by morphology control and microstructure modification, and presents many advantages in LIBs and the OER. In particular, FeNb11O29-x@C displays a large specific surface area, abundant active sites and a significant edge effect, thus improving the Li+ reactivity and OER kinetics. Meanwhile, the oxygen vacancies and lattice defects in FeNb11O29-x@C enhance the Li+ transport rate and reduce the OER barrier. In addition, the carbon layer structure not only inhibits the irreversible reaction between the electrolyte and metal ions, but promotes the stability, cycling ability and conductivity of LIBs and the OER. Generally, FeNb11O29-x@C demonstrates good electrochemical performance in LIBs (providing 240.8 mA h g-1 reversible capacity at a current density of 0.25C and just 0.98% capacity attenuation after 500 cycles at a current density of 10C). Again, it also shows high catalytic performance in the OER (a low overpotential (290 mV@10 mA cm-2), a small Tafel slope (44.4 mV dec-1) and desirable catalytic stability).