Metal–organic framework (MOF)-derived porous carbon has attracted particular attention in the electrochemical energy storage field, of which the key is the design and preparation of electrode materials with adjustable porosity and defects for supercapacitors. Here, a novel strategy of coating ZIF-8 with coal tar pitch (CTP) is presented to tailor the porosity and defects of derived porous carbon, by which the inward contraction of ZIF-8 is prevented to enlarge the ultra-micropores, and the defects of ZIF-8-derived carbon are repaired to form a continuous conjugated network. The tradeoff between porosity and electrical conductivity endows this novel hard/soft carbon electrode with fast ion/electron diffusion, achieving high yet balanced capacitance and rate performance of a top-level specific area-normalized capacitance (40 μF cm⁻²) and a capacitance retention of 52.1% at a 1000-fold increased current density. Meanwhile, the novel electrode realizes a high capacitance of 704 F g⁻¹ at 1 A g⁻¹ and capacitance retention of 91.9% after 50000 cycles in KOH + PPD electrolyte. This study provides an effective approach to designing novel hard/soft carbon with tuned porosity and carbon defects from MOFs and CTP for supercapacitors and other metal-ion batteries.

Heteroatom doping carbon materials exhibit a huge application potential for energy storage devices (ESDs). Herein, interconnected N/P co-doped carbon nanocage (NP-CNC) was synthesized from pyrene molecules by using nano-MgO as template and melamine-phytic acid supramolecular aggregate as dopant coupled with KOH activation. The as-prepared NP-CNC possesses interconnected nanocages for electron transportation and abundant micropores for ion adsorption. Moreover, co-doped N/P species in NP-CNC provide active sites and additional pseudocapacitance. Consequently, NP-CNC as electrode material for symmetric supercapacitor exhibits a high gravimetric capacitance of 435 F·g⁻¹ at 0.05 A·g⁻¹, high volumetric capacitance of 274 F·cm⁻³ at 0.032 A·cm⁻³, and long cycle lifespan with 96.1% capacitance retention after 50,000 cycles. Furthermore, NP-CNC as cathode for zinc-ion hybrid supercapacitor delivers satisfactory energy and power densities of 130.6 Wh·kg⁻¹ (82.3 Wh·L⁻¹) and 14.4 kW·kg⁻¹ (9.1 kW·L⁻¹). This work paves a promising approach to the preparation of high capacitance NP-CNC for ESDs.