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Aqueous zinc‐ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self‐doping from manganese metal–organic frameworks (Mn–MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self‐doped polyaniline cathode has a superior specific capacity (273 mAh g−1 at 0.5 A g−1), a high rate property (154 mAh g−1 at 20 A g−1), and excellent cyclability retention (87% over 4000 cycles at 15 A g−1). This research provides fresh insight into the development of innovative polymers as cathode materials for high‐performance AZIBs. [ABSTRACT FROM AUTHOR]

Polyaniline/CoRE x Fe 2− x O 4 (RE=La, Ce, Y, x =0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca . 10–20 nm. Microwave absorption properties of polyaniline/CoRE x Fe 2− x O 4 nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa x Fe 2− x O 4 nanocomposite, the optimal microwave absorption performance is at x =0.15, that is, the mass ratio of La in CoLa x Fe 2− x O 4 is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The functionalized graphene/polyaniline composite cathode showed high specific capacity and excellent rate performance. • A large conductive network was assembled by functionalized graphene and polyaniline. • The formation of -N-Zn-O- structure efficiently enhanced the Zn2+ storage behavior during discharging process. • A novel H+ and Zn2+ insertion mechanism was presented in this work. Polyaniline (PANI) as a typical conductive polymer has been widely applied in cathode materials of aqueous zinc ion battery (AZIB), owing to the features of high electronic conductivity and simple synthesized methods. However, the cycling instability caused of spontaneous deprotonation still limited the extensive application of PANI cathode materials. In this work, a functionalized commercial graphene (MEG) and PANI composite (MGP-1) was successfully assembled by a facile two-step method. When the MGP-1 acted as cathode material in AZIB, it demonstrated a high capacity of 184.5 mAh/g (0.2 A/g) and excellent rate performance of 137.6 mAh/g (3 A/g) compared to the PANI cathode. The corresponding analysis revealed that the boosted electrochemical behavior of MGP-1 was attributed to the large conductive network fabricated by the MEG and PANI, and the formations of -N-Zn-O- structures during discharging process. Moreover, based on the conventional H+ insertion mechanism, this work furtherly provided a H+ and Zn2+ insertion mechanism. In addition, the utilization of cheap and abundant commercial graphene would allow the graphene/polyaniline composite to be a promising cathode material applied in AZIB. [ABSTRACT FROM AUTHOR]