Controlling reaction kinetics of layered zinc vanadate having brucite-like Zn–O layers supported by pyrovanadate pillars for use in supercapacitors

Abstract Most of the layered metal oxides are relatively “open” structures and eventually find use in applications where charge intercalation or de-intercalation is critical. One of the limitations of layered structures is that they have a tendency to collapse after repeated cycling. In this study, it is established that use of single-phasic marteyite-type layered (Zn3V2O7(OH)2·2H2O) can be effectively extended in the field of energy storage devices. The pyrovanadate groups act as pillars and prevent the brucite-like Zn–O layers from collapsing. To induce further enhancement in the already stable materials, it is shown that the surface characteristics of these particles, with floriated morphology, can be easily tuned by tailoring the annealing temperature. Contrary to expectation, both the surface area and capacitive behavior showed improvement when the sample was annealed post-hydrothermal treatment for longer durations. Careful analysis, using large number of techniques, establish that this observation can be attributed to atomic rearrangement in the crystal unit cell and formation of cross-linked type particle morphology. This would lead to efficient path for charge transfer, which originate at the electrode-electrolyte interface. The samples showing interlinkages in the pores could deliver specific capacitance of ∼383 F g−1, which was ∼2.5 times higher in comparison to original porous particles. The particles continued to have ∼90% capacitance retention after 2000 cycles, which shows their potential as energy storage materials.