Regulation of-N-Zn-O- bonds via carbonized polymer dots in polyaniline composite cathode for high performance stable aqueous Zn-ion batteries

As one of the most important cathode materials for aqueous zinc-ion batteries (AZIBs), polyaniline (PANI) has attracted much attention because of its high electrical conductivity, simple synthesis procedure and excellent redox reversibility. However, the morphology of PANI macromolecules and its spontaneous deprotonation properties lead to low capacity and poor cycle stability, which limits its further application. To address these issues, in this work, PANI is in-situ prepared on the surface of carbon cloth (CC) through chemical oxidation polymerization under the presence of carbonized polymer dots (CPDs). Compared with pure PANI cathode electrodes, the materials with appropriate amount of CPDs (CPDs/PANI@CC-10) show a high specific discharge capacity of 168 mAh g(-1) at 0.1 A g(-1). Even at a high current density of 10 A g(-1), CPDs/PANI@CC-10 still exhibits a capacity of 102 mAh g(-1), and maintains 94.3 % of the capacity after 10,000 cycles. The profound mechanism investigation reveals that during the charge/discharge cycles, the percentage of protonated N greatly increases due to the addition of CPDs, and new NZnO bonds are formed, which is beneficial to more stable cycle and larger amount of Zn2+ storage. This work provides a new route for control the morphology and structure of PANI, which is of significant for its practical application in AZIBs.