Unraveling the Correlation between Structures of Carbon Nanospheres Derived from Polymeric Spheres and Their Electrochemical Performance to Achieve High-Rate Supercapacitors

Understanding correlation between the nanostructure of porous carbons and their ion transport behavior is critical for achieving high-performance supercapacitors. Herein, the relationship between size and shell thickness of carbon nanospheres (CNSs) and capacitive electrochemical performance is clarified. Structural uniform CNSs with controlled diameters, prepared via template-free interfacial copolymerization, are emerging as an ideal platform for investigating the ion transport behavior. It is found that ionic transport is significantly enhanced while the introduction of hollow cores with thinner shell, by virtue of the hollow nanopore-accelerated mass transport to reduce ion diffusion length. The proof-of-concept supercapacitors, constituted of carbons with diameter and shell thickness of 91 and 28 nm, respectively, can maintain highest capacitance retention ratio of 86% at a high sweep rate of 300 mVs(-1), also far outperforming the commercial activated carbon in terms of capacitance, rate capability, and surface efficiency, promising a brilliant application.