Aqueous multivalent ion batteries, especially aqueous zinc-ion batteries (ZIBs), have promising energy storage application due to their unique merits of safety, high ionic conductivity, and high gravimetric energy density. To improve their electrochemical performance, polyaniline (PANI) is often chosen to suppress cathode dissolution. Herein, this work focuses on the zinc ion storage behavior of a PANI cathode. The energy storage mechanism of PANI is associated with four types of protonated/non-protonated amine or imine. The PANI cathode achieves a high capacity of 74 mAh g⁻¹ at 0.3 A g⁻¹ and maintains 48.4% of its initial discharge capacity after 1000 cycles. It also demonstrates an ultrahigh diffusion coefficient of 6.25 × 10⁻⁹~7.82 × 10⁻⁸ cm⁻² s⁻¹ during discharging and 7.69 × 10⁻¹⁰~1.81 × 10⁻⁷ cm⁻² s⁻¹ during charging processes, which is one or two orders of magnitude higher than other reported studies. This work sheds a light on developing PANI-composited cathodes in rechargeable aqueous ZIBs energy storage devices.

As a p-type multifunctional semiconductor, CuSe nanostructures show great promise in optoelectronic, sensing, and photocatalytic fields. Although great progress has been achieved, controllable synthesis of CuSe nanosheets (NSs) with a desirable spacial orientation and open frameworks remains a challenge, and their use in supercapacitors (SCs) has not been explored. Herein, a highly vertically oriented and interpenetrating CuSe NS film with open channels is deposited on an Au-coated polyethylene terephthalate substrate. Such CuSe NS films exhibit high specific capacitance (209 F g^–1) and can be used as a carbon black- and binder-free electrode to construct flexible, symmetric all-solid-state SCs, using polyvinyl alcohol–LiCl gel as the solid electrolyte. A device fabricated with such CuSe NS films exhibits high volumetric specific capacitance (30.17 mF cm^–3), good cycling stability, excellent flexibility, and desirable mechanical stability. The excellent performance of such devices results from the vertically oriented and interpenetrating configuration of CuSe NS building blocks, which can increase the available surface and facilitate the diffusion of electrolyte ions. Moreover, as a prototype for application, three such solid devices in series can be used to light up a red light-emitting diode.