Orchestrating Penta-Element Interplay in Gradient-porous Carbons for Advanced Sodium-Ion Hybrid Capacitors.

Abstract

Sodium-ion hybrid capacitors (SIHCs) offer a cutting-edge synergy between battery-level energy density and supercapacitor-like power density, yet face critical challenges in balancing the kinetic and capacity mismatch between Faradaic anodes and capacitive cathodes. Herein, we present a penta-element doped gradient-porous carbon (PE-GPC) with a nanosphere architecture, engineered with high-entropy principles and a gradual pore density variation to enhance mass transport and charge storage. Operando spectroscopy and machine learning potentials unveil a concerted penta-element interplay: Thiophene-like S configurations mediate dynamic redox processes, enabling pseudocapacitive Na+ and anion storage, while fluorine functionalities foster a self-rejuvenating NaF-rich solid electrolyte interphase (SEI), stabilizing long-term cycling. Meanwhile, the synergistic N/B/P triad engineers a hierarchical defect network that enhances electronic conductivity and fine-tunes ion adsorption energetics. This orchestrated interplay empowers the SIHC full-cell with a high energy density of 196 Wh kg-1, a formidable power density (10.4 kW kg-1), and an impressive 88.2% capacity retention after 9000 cycles. By establishing a high-entropy stabilization paradigm, this work paves the way for multi-ion storage architectures, offering a universal strategy to bridge the charge-transfer imbalance in advanced energy devices.