LAUSR

Abstract Although potassium-ion batteries (PIBs) are considered as promising candidate to lithum-ion batteries (LIBs) in the area where energy density is no longer the top priority, developing suitable anodes for PIBs is still a big challenge because of the large radius of potassium-ion, which limits the rate performace and cyclic stability. Herein, nitrogen/oxygen dual-doped hierarchically porous carbon/graphene composite (NOPC@G) has been prepared for potassium-ion storage. Thanks to the heteroatom-rich porous structure and conductive network induced by graphene, the ion diffusion and electronic transmission are enhanced, which make NOPC@G exhibit outstanding potassium storage performance in terms of high specific capacity (445 mAhg−1), high rate capability (112 mAhg−1 at 40 C) and excellent cyclic stability. Furthermore, when used as anode for potassium-ion capacitors (PICs), NOPC@G also exhibits an impressive electrochemical performance with a maximum energy density of 153 Wh kg−1 (with a power density of 120 W kg−1) and a maximum power density of 22.98 kW kg−1 (with an energy density of 57 Wh kg−1). The simple synthesis route combined with the desirable electrochemical performance makes NOPC@G a promising anode for potassium storage.