Hierarchical Porous Carbons for High-Rate Aqueous Supercapacitors: Tuning Pore Sizes by Molecular Design of Carbon Dots as Self-Templates.

Abstract

Rational pore-size regulation is central to high-performance electric double-layer capacitors, yet carbon dots (CDs) self-templating often yields overly micropore-dominated carbons with limited high-rate capability. Here, we tailor CDs by combining polyethyleneimine with four organic acids and convert them into porous carbons, eliminating high-temperature corrosive chemical activation. Systematic porosimetry reveals a direct link between CDs molecular architecture and the resulting pore-size distributions. Notably, a mesopore-enriching pathway is identified, allowing hierarchical micro/mesoporosity. The optimized sample (PC-PMDA) delivers 582 F g-1 at 1 A g-1 and retains 475 F g-1 at 60 A g-1 with an IR drop of 0.09 V. At a practical mass loading of 10 mg cm-2, 78% of the capacity (relative to that at low loading) is still retained. This study provided a mechanistic picture of pore generation by CDs self-templating.