Polyaniline/graphene oxide nanocomposite as an innovative cathode for high energy density aqueous zinc-ion batteries

In order to resolve hard processability, poor conductive and lower capacity of polyaniline(PANI), We design and obtain a nanofiber network polyaniline/graphene oxide(PGO) and polyaniline/graphene oxide/manganese dioxide(PMGO) composite cathode. They are synthesized by electrochemical in-situ intercalative polymerization on oxidized graphite paper and assembled with the zinc anode into aqueous Zn-ion batteries(AZIBs). The initial discharged specific capacity of the PGO cathode is 224 mAh·g-1, and it is lower than that of the PMGO electrode when it discharges at 200mA·g-1. However, the capacity can reach 345 mAh·g-1 with better stability and reversibility compared to the PMGO under the same discharge/charge conditions. Characterization analysis and electrochemical studies show that the PGO composite cathode provides a large specific surface and charge/discharge channel, which optimizes the electrochemical performance of the battery. We also propose a new energy storage mechanism for intercalating PANI into graphene oxide(GO) layers to construct a nano-three-dimensional(3D) network for AZIBs and a proton pool with a hydrogen bond network of the PGO electrode. It is profitable for hindering the polarization, facilitating the electrode reaction, and enhancing the capacity and stability. For these reasons, the storage performance of the PGO electrode is superior to the polyaniline cathode reported at present.