Abstract Malva nut-derived microporous carbons are synthesized and investigated as electro-active materials for electrochemical supercapacitors. The biomass precursor is suffered primary carbonizations via hydrothermal and annealing treatments, respectively, and then the bio-chars are activated by potassium hydroxide to form amorphous microporous carbon. The porous carbons possess high specific surface area (> 1842 m2 g−1) and well-developed micro-porosity (> 88%). >2.1 at. % nitrogen and over 3.8 at. % oxygen contents are also distributed in the carbon matrixes. Supercapacitor electrode enclosed the porous carbons exhibits specific capacitance of 312 F g−1 at a specific current of 1 A g−1, and shows excellent cycling stability with capacitance retention over 93% after 7500 cycles performed on 5 A g−1. A symmetric device assembled by the carbon material delivers specific capacitance of 247 F g−1 at a current density of 1 A g−1, and achieves the specific energy of 8.4 kg−1 with specific power of 246 W kg−1. Porous carbon obtained by annealing pre‑carbonization and chemical activation has relatively superior physicochemical properties and electrochemical performance. Results demonstrate that malva nut can be used as a potential precursor in the design of porous carbon for high-performance electrochemical capacitors.

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用于超级电容器的锦葵花微孔碳：一次碳化对结构和性能的影响

摘要 锦葵属坚果衍生的微孔碳作为电化学超级电容器的电活性材料被合成和研究。生物质前驱体分别通过水热和退火处理进行初级碳化，然后用氢氧化钾活化生物炭，形成无定形微孔碳。多孔碳具有高比表面积（> 1842 m2 g-1）和发达的微孔率（> 88%）。>2.1 处。% 氮和超过 3.8 at。% 的氧含量也分布在碳基质中。封闭多孔碳的超级电容器电极在 1 A g-1 的特定电流下表现出 312 F g-1 的比电容，并显示出优异的循环稳定性，在 5 A g-1 上进行 7500 次循环后电容保持率超过 93%。由碳材料组装的对称器件在 1 A g-1 的电流密度下提供 247 F g-1 的比电容，并以 246 W kg-1 的比功率实现 8.4 kg-1 的比能量。通过退火预炭化和化学活化获得的多孔碳具有相对优越的理化性能和电化学性能。结果表明，锦葵可用作高性能电化学电容器多孔碳设计的潜在前体。