Engineering 3D vertically-aligned lamellar-structured graphene incorporated with polypyrrole for thickness-independent zinc-ion hybrid supercapacitor.

Hybrid supercapacitors, inheriting the merits from supercapacitors and batteries, exhibit promise in energy storage technologies. However, they are bottlenecked by the sluggish diffusion, low mass loading and inadequate energy density. Herein, three-dimensional vertical orientation graphene-polypyrrole thick electrode (PPy@3DVAG) with vertically-aligned channels and three-dimensional conductive networks prepared via in-situ gas phase polymerization is proposed for high-energy-power zinc-ion hybrid supercapacitors to efficiently mitigate these issues. Based on the "dual-ion" storage mechanism, and associated with the multiple synergy of short mass/charge transfer pathway, fast kinetics and enhanced electroactivity endowed by the structurally engineering of thick electrode, even at the high active mass-loading (8.4 mg cm-2), the Zn-based hybrid energy devices with PPy@ 3DVAG-70 as cathode electrode exhibits intriguing capacitive performances, including exceptional high areal capacitance of 927 mF cm-2, good rate performance (53% at current density of 15 mA cm-2) and excellent areal energy/power density of 360.4 μWh cm-2 and 10.125 mW cm-2. The presented results highlight the facile and efficient approach for structural engineering the active cathode material, significantly contributing to the rapid development of eco-friendly and scalable Zn-based hybrid energy devices. • Three-dimensional vertical-orientation graphene-polypyrrole electrode is constructed. • High areal capacitance and excellent areal energy/power density are obtained. • Zn2+ ions storage of polypyrrole is realized to be a "dual-ion" storage mechanism. [ABSTRACT FROM AUTHOR]