Regulation of dual-atom doped porous carbon towards high-performance capacitive storage devices†

Abstract

Zinc ion capacitors show impressive energy storage potential for well-balanced energy and power density, but exploring their implicit energy storage mechanism is crucial and still challenging. Herein, a new viewpoint is proposed for regulating nitrogen and oxygen dual-doped carbon with short-range order by sustaining the conductivity and synchronously boosting interfacial chemisorption sites. The artful nanoarchitecture engineering of a cross-linked carbon framework with a high specific surface area (2702.3 m² g⁻¹) is beneficial for efficient electrolyte penetration and ion transfer, thus enhancing the electrode's capacitance and rate performance. Based on electrochemical capacitor properties and theoretical calculations, the optimized hetero-carbon used for zinc ion capacitors could deliver a high capacity of 241.1 mA h g⁻¹ at 0.1 A g⁻¹ and an energy density of 191.6 W h kg⁻¹. The dynamic potential of zincate hydrated ion precipitation/dissolution behavior was explored by ex situ X-ray diffraction and photoelectron spectroscopy experiments. This work not only provides new perception integration with porousness and nanoarchitecture engineering in carbon materials, but also sheds light on the zinc-ion capacitor storage mechanism.