Antimony/reduced graphene oxide composites as advanced anodes for potassium ion batteries

The abundance of sodium and potassium elements in the earth has trigged great research interests in Na-ion and K-ion batteries. Compared to Li-ion batteries, slashed fabrication cost has been predicated for Na-ion and K-ion batteries, making them promising candidates for stationary energy storage. Potassium ion has a much larger radius than that of lithium ion, which would lead to a more severe volume change during K ions insertion. An intriguing question is whether the electrode optimization strategies developed in Li-ion batteries could be extended to K-ion batteries. In this study, Sb is used as a model alloy anode to explore the effect of nanocarbon incorporation on the cyclic stability. Through the preparation of Sb/reduced graphene oxide composite electrode, a reversible capacity of over 300 mAh/g is obtained with decent capacity retention. In contrast, neat Sb shows a fast capacity fading due to the volume expansion during alloying with K ions. This study suggests that the preparation of alloy/nanocarbon composite remains an effective approach in developing advanced anodes for K-ion batteries.Graphical AbstractSchematic of the materials synthesis process: (a) GO precursor; (b) Adsorption of Sb3+ on the surface of GO and (c) thermal annealing to reduce GO (into -rGO) and SbCl3 (into Sb) nanoparticles. [GRAPHICS]