The
biggest challenge of potassium-ion batteries (KIBs) application
is to develop high-performance electrode materials to accommodate
the potassium ions large size. Herein, by rational design, we carbonize
three-dimensional (3D) ordered macroporous ZIF-8 to fabricate 3D interconnected
nitrogen-doped hierarchical porous carbon (N-HPC) that shows excellent
rate performance (94 mAh g–1 at 10.0 A g–1), unprecedented cycle stability (157 mA g–1 after
12000 cycles at 2.0 A g–1), and superior reversible
capacity (292 mAh g–1 at 0.1 A g–1). The 3D hierarchical porous structure diminishes the diffusion
distance for both ions/electrons, while N-doping improves the reactivity
and electronic conductivity via producing more defects. In addition,
the bicontinuous structure possesses a large specific surface area,
decreasing the current density, again improving the rate performance. In situ Raman spectra analysis confirms the potassiation
and depotassiation in the N-HPC are highly reversible processes. The
galvanostatic intermittent titration measurement and first-principles
calculations reveal that the interconnected macropores are more beneficial
to the diffusion of the K+. This 3D interpenetrating structure
demonstrates a superiority for energy storage applications.