Carbon Nitride Pillared Vanadate Via Chemical Pre-Intercalation Towards High-Performance Aqueous Zinc-Ion Batteries

Vanadium based compounds are promising cathode materials for aqueous zinc (Zn)-ion batteries (AZIBs) due to their high specific capacity. However, the narrow interlayer spacing, low intrinsic conductivity and the vanadium dissolution still restrict their further application. Herein, we present an oxygen-deficient vanadate pillared by carbon nitride (C3N4) as the cathode for AZIBs through a facile self-engaged hydrothermal strategy. Of note, C3N4 nanosheets can act as both the nitrogen source and pre-intercalation species to transform the orthorhombic V2O5 into layered NH4V4O10 with expanded interlayer spacing. Owing to the pillared structure and abundant oxygen vacancies, both the Zn2+ ion (de)intercalation kinetics and the ionic conductivity in the NH4V4O10 cathode are promoted. As a result, the NH4V4O10 cathode delivers exceptional Zn-ion storage ability with a high specific capacity of about 370 mAh g(-1) at 0.5 A g(-1), a high-rate capability of 194.7 mAh g(-1) at 20 A g(-1) and a stable cycling performance of 10 000 cycles.