中空分级多孔炭球的制备及其电化学性能研究

Preparation of Hollow Hierarchical Porous Carbon Spheres for Electrochemical Performance

摘要: 本文以十二烷基硫酸钠(SDS)为软模板剂，D-核糖为碳源，聚(4-苯乙烯磺酸–共聚–马来酸)钠盐(PSSMA)为稳定剂，采用水热炭化和CO₂活化方法制备了中空分级多孔炭球，系统考察了其电化学性能。研究表明，SDS和PSSMA发生相互作用形成混合乳液，作为水热反应的中空微反应器。D-核糖在微反应器与水的界面发生水解、聚合和芳构化等过程并形成炭前驱体，经炭化和CO₂活化制得微孔、介孔和大孔并存的中空分级多孔炭球。该炭球具有较高的比表面积、中空的球形腔体、分级的孔隙结构和丰富的表面含氧官能团，有利于电解液和离子的存储、浸润和扩散。当CO₂活化时间为1 h时，样品(HPC-1)的比表面积为316 m²∙g⁻¹，孔容积为0.19 cm³∙g⁻¹，表面分布着大量羧基(-COOH)和羟基(-OH)等含氧官能团，表现出最佳的电化学性能。以6 mol∙L⁻¹ KOH为电解液，在三电极体系下，当电流密度为0.2 A∙g⁻¹时，比电容为183 F∙g⁻¹；电流密度为5 A∙g⁻¹时进行5000次充放电循环后比电容保持率仍可达96%；二电极体系下，当电流密度为0.1 A∙g⁻¹，比电容为97 F∙g⁻¹，当功率密度为50 W∙kg⁻¹时，能量密度可达3.36 W∙h∙kg⁻¹，表现出良好的应用潜能。

Abstract: This study employs sodium dodecyl sulfate (SDS) as a soft template agent, D-ribose as a carbon source, and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) as a stabilizer to prepare hollow hierarchical porous carbon spheres through hydrothermal carbonization and CO₂ activation, and investigates their electrochemical performance. The research indicates that SDS and PSSMA interact to form a mixed emulsion, serving as a hollow micro-reactor for the hydrothermal reaction. D-ribose undergoes hydrolysis, polymerization, and aromatization at the interface of the micro-reactor and water, forming a carbon precursor. The resulting hollow hierarchical porous carbon spheres feature the coexistence of micropores, mesopores, and macropores, a high specific surface area, a hollow spherical cavity, a hierarchical pore structure, and abundant oxygen-containing functional groups on the surface, which facilitate the storage, wetting, and diffusion of electrolytes and ions. When the CO₂ activation time is 1 h, the sample (HPC-1) exhibits a specific surface area of 316 m²∙g⁻¹, a pore volume of 0.19 cm³∙g⁻¹, and surface oxygen-containing functional groups such as carboxyl (-COOH) and hydroxyl (-OH), demonstrating optimal electrochemical performance. Using 6 mol∙L⁻¹ KOH as the electrolyte, in a three-electrode system, the specific capacitance reaches 183 F∙g⁻¹ at a current density of 0.2 A∙g⁻¹, and after 5000 charge-discharge cycles at 5 A∙g⁻¹, the specific capacitance retention rate remains at 96%. In a two-electrode system, the specific capacitance reaches 97 F∙g⁻¹ at a current density of 0.1 A∙g⁻¹, and at a power density of 50 W∙kg⁻¹, the energy density reaches 3.36 W∙h∙kg⁻¹, showing promising application potential.