A crystal splitting growth and self-assembly route to carbon superstructures with high energy and superstable Zn-ion storage

Abstract

The sluggish ion-migration kinetics and structural instability are critical limits of isolated single-level carbon structures, inhibiting capacitive activity and durability of Zn-ion capacitors. To conquer the roadblocks, making well-defined arrangement of low-dimensional building blocks into integrative carbon superstructures gives a promising solution, but remains challenging. Herein, we report a crystal splitting growth and self-assembly strategy to customize nanorod-integrated carbon superstructures for activating superior Zn-ion storage. The coordination between 3-aminobenzoic acid as an organic linker and Cu2+ as a metal node triggers the crystal splitting growth of polymeric clusters to yield nanorod modules, which further couple with 4,4′-bipyridine to self-assemble into exquisite superstructures. Featured with well-arranged one-piece topographies and beneficial diheteroatomic attributes, the robust carbon superstructures empower fast ion transport and easy accessibility of zincophilic sites with low energy barriers. The fabricated Zn-ion capacitors thus deliver ultrahigh energy density (157 Wh kg−1) and extraordinary cyclability (300,000 cycles@20 A g−1). Systematic studies identify the root of excellent electrochemical metrics as high-kinetics alternately physical uptake of Zn2+/SO42− charge carriers and multielectron chemical redox reaction of pyridine/carbonyl motifs with Zn2+ to form N−Zn−O bonds. This work provides new avenues to engineer carbon superstructures for propelling advanced energy storage.