Algal residues-engaged formation of novel WVO4/V3Se4 hybrid nanostructure with carbon fiber confinement for enhanced long-term cycling stability in sodium/potassium storage

Designing high capacity, superior rate, satisfactory cycle stability as well as green, low cost, and earth abundant electrode materials is critical for sodium and potassium ion storage. Herein, the first example of synthesizing the heterostructure between WVO4 and V3Se4 embedded in carbon fiber (WVO4/V3Se4/CNFs) as a high capacity and stable anode for sodium (SIBs) and potassium-ion batteries (PIBs) is reported. The composite is skillfully constructing by electrospinning method followed with heat treatment, with the assistance of biomass algae (Chlorella) as adsorbent and reactor. Owing to the unique advantages of hybrid structure and carbon sheaths, the composite architecture demonstrates high reversible capacity, excellent rate properties, and long-term cyclic stability. For sodium storage, the WVO4/V3Se4/CNFs electrode exhibits a high reversible specific capacity of 446 mAh g−1 at 50 mA g−1 after 200 cycles as well as a promising long cycling stability with a high capacity of 137 mAh g−1 at 5 A g−1 even over 25,000 cycles. More importantly, it also delivers high reversible capacity and good rate capability for potassium storage. This work opens up new way for developing satisfied metal oxide anode materials for SIBs and PIBs.