Printed zinc ion battery with excellent rate performance utilizing carbon-intercalated vanadium oxide cathode for flexible wearable electronics

Abstract

Rechargeable aqueous Zn-ion batteries (AZIBs) are considered as promising practical energy storage devices for flexible electronics due to their natural safety, eco-friendliness, and the abundant mineral resources of Zn. However, the poor capacity and unsatisfactory cycle stability at high current densities hinder the practical application of flexible ZIBs. Herein, a nitrogen-doped carbon intercalated vanadium oxide (CNVO) nanosheets are synthesized by introducing polyaniline into vanadium oxide interlayers and in-situ carbonization. The incorporation of nitrogen-doped carbon improves the conductivity of CNVO via π-d conjugation and facilitates Zn²⁺ migration by expanding the interlayer spacing. Moreover, the substantial specific surface area and the abundant oxygen vacancy defects of CNVO, furnishes numerous active sites for Zn²⁺ intercalation, significantly enhancing the pseudocapacitive performance and resulting in excellent high-rate capabilities. Consequently, the CNVO//Zn battery exhibits a discharge capacity of up to 200 mAh g⁻¹ even at a high current density of 10 A g⁻¹ and long-term durability of 2000 cycles. Furthermore, a flexible CNVO//Zn battery is fabricated using screen printing technology, demonstrating an energy density of 2.03 mWh cm⁻² and a power density of 1.37 mW cm⁻².