Unravelling the effect of benzoquinone intercalators on the aqueous zinc-ion storage performance toward a vanadium pentoxide cathode

Intercalating vanadium pentoxide (V2O5) with organic molecules has emerged as an efficient approach for boosting the performance of aqueous zinc-ion batteries (ZIBs). However, the effect of molecular properties on the related electrochemical energy storage is rarely explored. Herein, we systematically compared the performance of three benzoquinone-intercalated V2O5 electrodes which can be easily synthesized through a one-step hydrothermal reaction. The V2O5 intercalated by tetrabromo-benzoquinone (denoted as V2O5-BQ4Br) shows an outstanding capacity of 477 mA h g-1 at 0.3 A g-1 and better cycle performance (93.7%/75.1% capacity retention after 100/5000 cycles at 0.5/3 A g-1) than that of V2O5 treated with benzoquinone (V2O5-BQ) and tetrafluoro-benzoquinone (V2O5-BQ4F). DFT calculations reveal lower binding energy, faster Zn2+ migration and faster internal charge transfer for V2O5-BQ4Br. Furthermore, ex situ characterizations confirms that the energy storage process includes the Zn2+ intercalation, quinone carbonyl conversion and V valence transition with high reversibility. The comparative investigation of benzoquinone intercalators can guide the development of organic molecules intercalating two-dimensional oxides for robust ZIB applications. We demonstrate V2O5 cathodes with benzoquinones intercalation. The intercalated BQ4Br expands V2O5 lattices and improves reaction kinetics, endowing V2O5-BQ4Br with higher capacity and cycle stability.

Automated summary

In this study, the performance of three benzoquinone-intercalated V2O5 electrodes was systematically compared. The V2O5 intercalated by tetrabromo-benzoquinone showed outstanding capacity and cycle stability. DFT calculations and ex situ characterizations confirmed the reversibility of the intercalation process. The investigation of benzoquinone intercalators can guide the development of organic molecules intercalating two-dimensional oxides for robust ZIB applications.