γ′-V2O5 Polymorph: A Genuine Zn Intercalation Material for Nonaqueous Rechargeable Batteries

Electrochemical properties of the puckered layered gamma'-V2O5 polymorph as a cathode material in a nonaqueous Zn metal cell using the acetonitrile-Zn(CF3SO3)(2) electrolyte are investigated here for the first time. A typical galvanostatic profile in the 2-0.3 V vs Zn2+/Zn voltage range shows a sloping discharge curve involving a capacity of 130 mAh g(-1) at C/20 in one single step centered at 0.9 V vs Zn2+/Zn. The structural response of gamma'-V2O5 during the discharge-charge cycle is investigated by ex situ X-ray diffraction (XRD) and Raman spectroscopy. Up to 0.41 Zn mol(-1) can be accommodated between the gamma'-V2O5 layers, inducing only a moderate interlayer expansion of +6.4%, comparable to that found for Li+ insertion. Remarkably, the insertion process is fully reversible in spite of the high charge density of Zn2+. Good cycle life can be achieved at a moderate rate, with a stable capacity of nearly 130 mAh g(-1) available at 0.9 V vs Zn2+/Zn over at least 60 cycles. The peculiar structural features of the new electroformed Zn0.41V2O5 bronze highlight the interest of the gamma'-V2O5 polymorph to mitigate the expected large deformation upon electrochemical divalent Zn2+ incorporation.

Automated summary

The electrochemical properties of the puckered layered gamma'-V2O5 polymorph as a cathode material in a nonaqueous Zn metal cell using the acetonitrile-Zn(CF3SO3)(2) electrolyte have been investigated for the first time, showing good reversibility and stable capacity with around 130 mAh g(-1) available over at least 60 cycles. The unique structural features of the Zn0.41V2O5 bronze formed through electrochemistry highlight the potential of the gamma'-V2O5 polymorph to mitigate large deformation during electrochemical divalent Zn2+ incorporation.