Gradient Pores Enhance Charge Storage Density of Carbonaceous Cathodes for Zn‐Ion Capacitor

Abstract Engineering carbonaceous cathode materials with adequately accessible active sites is crucial for unleashing their charge storage potential. Herein, activated meso‐microporous shell carbon (MMSC‐A) nanofibers are constructed to enhance the zinc ion storage density by forming a gradient‐pore structure. A dominating pore size of 0.86 nm is tailored to cater for the solvated [Zn(H 2 O) 6 ] 2+ . Moreover, these gradient porous nanofibers feature rapid ion/electron dual conduction pathways and offer abundant active surfaces with high affinity to electrolyte. When employed in Zn‐ion capacitors (ZICs), the electrode delivers significantly enhanced capacity (257 mAh g −1 ), energy density (200 Wh kg −1 at 78…

• NN
  National Natural Science Foundation of China

  Awards: 52072283, 52127816
• NK
  National Key Research and Development Program of China

  Award: 2020YFA0715000