Preparation and Energy Storage Performance of High Specific Capacity Hydrochloric Acid-Doped Polyaniline Composite Electrode

Conductive polyaniline (PANI) has become a research hotspot for aqueous zinc-ion battery materials due to its reversible oxidation property. To inhibit conductivity reduction and instability caused by dedoping and degradation, graphene is usually used for composite modification. However, the internal structure of graphene/PANI composite materials prepared by traditional chemical oxidation methods is not excellent enough, and the specific capacity of polyaniline doped with commonly used dopants (such as SO42-) is not ideal because of the low proton/mass ratio. An electrochemical polymerization method was applied to polymerize a hydrochloric acid- doped PANI composite electrode (G- PANI) in situ on the surface of exfoliated graphene. An orthogonal experiment is explored to determine the optimal preparation process, and it was combined with a zinc anode to form a secondary battery, to investigate its energy storage properties. Attribute to the large number of active polymerization sites provided on the surface of graphene, PANI grows in the form of nanofibers. Finally, PANI and graphene were effectively coupled inside the composite electrode to build a three- dimensional nano-conductive network structure. This structure can promote the energy density of the electrode and stabilize electrode performance on the premise of increasing the charge delocalization of polyaniline as well as the conductivity. Electrochemical analysis shows that at a discharge current density of 0.4 A/g, it exhibits an average high specific capacity of 355.0 mA · h/g during the initial 5-cycle of discharge; at a discharge current density of 1 A/g, the initial 5-cycle of discharge process also has an average specific volume of 282.7 mA · h/g. Compared with sulfuric acid-doped polyaniline electrodes, it has a higher capacity and is suitable for large current discharge, and good rate performance. © 2024 Sichuan University. All rights reserved.