Solvent-guided nanoarchitecturing of heterodiatomic carbon superstructures for high-performance zinc-ion hybrid capacitors

Abstract

Designing well-structured carbon nanomaterials is crucial for promoting zinc-ion hybrid capacitors with high-kinetics and large-current Zn2+-storage viability. Herein we report the solvent-guided nanoarchitecturing of polyimide precursor to customize versatile heterodiatomic carbon superstructures (CS). Modulating the solvent-precursor interaction through a solubility parameter model and molecular dynamic simulation optimizes the thermodynamic solubilization (–2.14 eV) and growth kinetics (–9.22 eV) of polymeric intermediates with a minimum energy obstruction. The solvent-optimized CS exhibit well-defined spherical topology, ion-compatible pore channels and favorable dual-function motifs, affording more ample-exposed zincophilic platforms and high-speed ion transport routes. As a consequence, the assembled Zn||CS hybrid capacitor activates superior electrochemical activity and durability, including superior rate capacities (240 mAh g−1 at 0.5 A g−1, 108 mAh g−1 at 100 A g−1), high energy density (145 Wh kg−1) and ultralong lifespan (300,000 cycles at 50 A g−1). Marriage of experimental studies and theoretical calculations unravel the alternate storage of opposite charges in CS cathode, which involves high-kinetics physical Zn2+/CF3SO3− uptake at zincophilic sites and chemical redox of Zn2+ ions with carbonyl/pyridine motifs to initiate O−Zn−N bonds. Molecular dynamics simulations demonstrate that diffusion kinetics of Zn2+ ions is greatly facilitated by > 10 Å micropores with low energy barriers, but is blocked by < 7 Å micropores. This work provides new insights into the structural engineering of carbon superstructures for advanced energy storage.