Synergistic enhancement of aqueous zinc-ion battery performance via intercalated and in-situ polymerization of poly(3,4-ethylenedioxythiophene)

The burgeoning demand for sustainable energy storage solutions has intensified the pursuit of vanadium-based cathodes for aqueous zinc-ion batteries (AZIBs). However, their performance has been hampered by the limited interlayer space, poor electrical conductivity and unstable layer structure during the cycling working process. Herein, a hybrid vanadium-based composite cathode material was synthesized by in-situ polymerization to integrate poly(3,4-ethylenedioxythiophene) (PEDOT) within the interlayers of Zn x V 2 O 5 · n H 2 O (ZVO). A variety of experimental data demonstrate that this in-situ interlayer polymerization strategy successfully induces enlarged interplanar space, valence changes of vanadium, and regular arrangement of the conductive PEDOT chain between the vanadium bronze interlayers. As a result, the ion diffusion kinetics, electron transport rate, and pseudocapacity of the prepared hybrid cathode are all improved, leading to excellent electrochemical performance with high specific capacity (420.1 mAh·g −1 at 50 mA·g −1 ) and good cycling performance (capacity retention of 303.3 mAh·g −1 after 1000 cycles at 1 A·g −1 ) compared with other reported vanadium bronze cathodes in AZIBs. This study provides a facile synthesis strategy by in-situ interlayer polymerization without any oxidant, which can potentially be applied to the fabrication of other organic-inorganic hybrid cathodes. • The interlayer in-situ polymerization method without extra oxidant simplified the fabrication process of AZIBs cathodes. • The AZIBs performances improved by introducing uniformly dispersed PEDOT chains, low valence vanadium and oxygen defects. • This strategy led to a high specific capacity of 420.1 mAh·g −1 at 50 mA·g −1 and maintained 303.3 mAh·g −1 after 1000 cycles.