Dendrite growth inhibition in a V6O13 nanorods based non-aqueous Zn-ion battery by a scalable polycarbazole@Carbon nanotubes overlayer

Inhibiting the growth of dendrites, one of the most serious issues faced by zinc-ion batteries (ZIBs) is addressed by coating the Zn anode with a layer of poly(carbazole)-carbon nanotubes (PCz@CNTs) composite. The electrically conducting robust composite overlayer ensures that the Zn-deposition during charging cycles is homogeneous and completely free of any fiber-like growth. This is confirmed from the cross-sectional electron microscopy analysis of post-cycled PCz@CNTs@Zn electrode. A vanadium oxide nanorods-porous graphitic flakes (V6O13 NRs@PGFs) composite is used as a cathode. It has a large specific surface area, affording short ion-diffusion distances and many vacant sites thus permitting facile Zn2+ ion ingress and egress, is used. A remarkable performance results for the non-aqueous ZIB: V6O13 NRs@PGFs//PCz@CNTs@Zn with a capacity of 286 mAh g−1 after 300 cycles at 30 mA g−1 (with 98% capacity retention), energy density of ∼172 Wh kg−1 and a nominal voltage of 1.8 V. It is significantly enhanced compared to its analogous ZIB of V6O13 NRs@PGFs//Zn (193 mAh g−1, and 80% capacity retention). The PCzCNTs overlayer imparts long lifespan with nominal capacity fade, guarantees ultra-safe operation, is cost-effective and also easy to scale-up thus providing a solution that can be adapted to other metal-ion batteries free of dendrites and long term cycling stability.