The Li3V2(PO4)3@C materials prepared by freeze-drying assisted sol-gel method for an aqueous zinc ion hybrid battery

In this paper, fast ion and electron delivery inside electrode materials, which is very crucial to the aqueous zincion hybrid batteries (AZHBs), has been studied in order to achieve the excellent electrochemical performance. The Li3V2(PO4)3@C (LVP@C) composites were successfully fabricated by freeze-drying assisted sol-gel method, and the effects of carbon content on the structure, morphology and electrochemical performance of LVP@C composites were investigated. XRD results suggested that the products were made up of an ideal monoclinic structure of LVP, and the structural changes of Li+ intercalation and de-intercalation during charge-discharge process were verified. Particularly, the LVP@C-05 sample exhibits excellent crystallinity. SEM images presented that with the increase of carbon content, the size of particles is smaller, and the distribution of particles is more uniform and dispersed. Especially, the LVP@C-05 sample has the smallest and the most uniform dispersed particles. The charging-discharging results indicated that the LVP@C-05 sample delivers the highest initial capacity of 95mAh g-1 at the current density of 2C, and the capacity retention after 50th cycles is 91%. Even at 20C current density, the LVP@C-05 also shows an attractive discharge capacity as high as 67mAh g-1. CV results presented that the ionic diffusion coefficient of the LVP@C-05 sample is the highest (2.59x10-12 cm2 s-1), compared to the value of LVP@C-0, LVP@C-03, LVP@C-07 sample. Besides, EIS and Nyquist plots fitting results indicated that the Rct of LVP@C-05 sample is the lowest (189.5 omega), showing a lower charge transfer resistance and increasing the kinetics of the reaction.

Automated summary

This study investigates the fast ion and electron delivery inside electrode materials for aqueous zincion hybrid batteries. Composites of LVP@C were successfully fabricated, with the LVP@C-05 sample showing the best electrochemical performance due to its excellent crystallinity and uniform particle distribution. In terms of charging-discharging and CV results, LVP@C-05 exhibited the highest initial capacity and ionic diffusion coefficient, as well as the lowest charge transfer resistance among the samples tested.