context: The electrochemical performance of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors was tested by cyclic voltammetry and galvanostatic charge–discharge tests within the voltage range of 0–2.0 V (Fig. 5). The CV curves of the hybrid ion capacitors at various scan rates from 10 mV s−1 to 200 mV s−1 maintain a quasi-rectangular shape, suggesting an EDLC-type behavior (Fig. 5a). Fig. 5b shows the voltage curves of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors at various current densities from 0.5–30 A g−1. The symmetric and linear shape of the curves in the graph can be observed corresponding to the results of the CV test. At a current density of 1 A g−1, the bare Zn–AC hybrid ion supercapacitors failed after 10 cycles, while the PAM/PVP-coated Zn–AC hybrid ion supercapacitors show a good cycling stability (Fig. S10†). This superior stability can be attributed to the critical role of the PAM/PVP layer coated on the zinc anode acting as an inhibitor on the O2/water interphase and a distributor of ions during the zinc deposition. The PAM/PVP-coated Zn–AC hybrid ion supercapacitors show an excellent rate capability of 336, 292, 264, 232, 220, 195, 190, 175, and 165 F g−1 at a current density of 0.5, 1, 2, 5, 8, 10, 15, 20, 25, and 30 A g−1 (Fig. 5c and S11†). The galvanostatic charge–discharge curves and long cycling stability of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors at a current density of 15 A g−1 are shown in Fig. 5d and e. The specific capacitance of the devices slightly increases at first due to activation, then remains quite stable, and ultimately gives a high retention of 100% of the initial specific capacitance after 6000 cycles. These results further demonstrate the excellent electrochemical performance of the Zn–AC hybrid ion supercapacitors with the PAM/PVP layer. Notably, the PAM/PVP-coated Zn–AC hybrid ion supercapacitors have a high energy density of 118 W h−1 kg−1 and a power density of 17.9 kW kg−1 (based on the mass of AC materials, Fig. S12†), where the energy density is superior to those of the bare Zn–AC hybrid ion supercapacitors (Fig. S13 and Table S1†).