Building 1D nanofibers with controlled porosity and crystallinity for honeycomb-layered oxide to achieve fast ion kinetics and superior sodium storage performance

The exploration of sodium ion batteries (SIBs) cathodes with high voltage and high performance has stimulated the research on the honeycomb-layered oxides. However, their performance are severely restricted by the slow ion intercalation kinetics and inferior high rate capability. Herein, 1D nanofibers with controlled morphology and crystallinity have been constructed for the honeycomb-layered Na3Ni2BiO6 and Na3Ni2SbO6. The formation mechanisms of the nanofibers are probed. The significant effects of the porosity and particle crystallinity on ion transport kinetics and electrochemical properties of the oxide nanofibers are studied. Notably, the highly porous structure and low particle crystallinity are highly effective on promoting fast ion transport and improving high rate properties. Surprisingly, both modified nanofibers with uniform porous structure and low-crystallized nanoparticles achieve the better rate capability and faster ion transport capability than the reference samples. Moreover, the excellent sodium storage performance and stable high-rate cycling properties further demonstrate the high efficiency of 1D porous architecture on reversible sodium intercalation.