Sanitary tissue is utilized as the precursor to construct a hard carbon microbelt paper (HCMB), which can be employed as a high-initial-coulombic-efficiency and low-discharge-platform K⁺-storage anode for 4.5 V hybrid capacitors.

Nanocage-like 3D porous graphitic carbon nitride (g-C₃N₄) with a high surface area and nitrogen defects was successfully prepared via a novel, template-free, cost-effective and hydrothermal-copolymerization route.