Owing to the unique redox reaction and the relative low molar mass of the repeating unit, poly(N-vinylcarbazole) (PVK) was selected as an advanced organic cathode for potassium-ion-based dual-ion battery (PDIB) with the K foil anode and KPF6-based electrolyte. The operation mechanism of this PDIB is that PF6- anions are migrated from the electrolyte and incorporated into PVK cathode via the attraction to the positively charged N atom of carbazole ligand, and then are released into the electrolyte in the subsequent discharge process; simultaneously, K+ cations are reversibly stored/removed in/from the anode during charging/discharging. It shows a high median operation potential of 4.05 V vs. K+/K and can achieve a high specific capacity of 117 mAh g(-1) at 20 mA g(-1), which is close to its theoretical value of 138mAh g(-1). More impressively, even at the highest current density of 2000 mA g(-1) for 500 cycles, a high average specific capacity of 61 mAh g(-1) can still be obtained with capacity rentation of 55%. (C) 2018 Elsevier Ltd. All rights reserved.