Oxygen-enriched porous electroactive carbon (OPEC) is prepared by simply carbonizing salted seaweed and only washing with water. The recrystallized NaCl cube is chemically stable and mainly acts as a pore filler in the pristine seaweed. It helps to maintain the innate pore system and simultaneously templates the formation of square pores. Its shielding effect not only enhances the onset decomposition temperature but also helps to achieve high yield. It can also be completely removed by washing with the green solvent water. The obtained OPEC-800 material not only shows a specific surface area of 329.3 m² g⁻¹ but also a microporous structure (0.8–2.0 nm) matching with the electrolyte 1.0 M H₂SO₄. It exhibits a specific capacitance of 324.3 F g⁻¹ (specific surface-area capacitance is 98.5 μF cm⁻²) at a current density of 0.50 A g⁻¹ in a three-electrode system. Its high oxygen content of 19.1% can lead to a wide operating voltage window of 0.0–1.40 V and an attractive energy density of 15.9 W h kg⁻¹ at a power density of 175.0 W kg⁻¹ in a two-electrode system. Furthermore, it also displays an excellent cyclic stability (98%, 10 000 cycles) and good rate performance. The whole process is a green, oxidant-free, acid-free, and low-cost method for converting green biomass into self-functionalized carbon with naturally connected pores aiming to fabricate green energy devices. All the attractive features make the environmentally friendly route a competitive candidate for preparing other porous electroactive materials.

中文翻译：

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用盐渍海藻无酸合成具有独特方孔的富氧电活性炭，可制得具有诱人能量密度的坚固型超级电容器

富氧多孔电活性炭（OPEC）是通过简单地将盐渍海藻碳化并仅用水洗涤来制备的。重结晶的NaCl立方体化学性质稳定，主要用作原始海藻中的孔隙填充剂。它有助于保持先天的毛孔系统，并同时模板化方孔的形成。其屏蔽作用不仅提高了起始分解温度，而且还有助于实现高收率。也可以通过用绿色溶剂水洗涤将其完全除去。所得的OPEC-800材料不仅具有329.3 m ² g ^-1的比表面积，而且具有与电解质1.0 MH ₂ SO ₄匹配的微孔结构（0.8-2.0 nm）。。在三电极系统中，在0.50 A g ^-1的电流密度下，它表现出的比电容为324.3 F g ^-1（比表面积电容为98.5μFcm ^-2）。的19.1％的高氧含量可导致0.0-1.40 V的宽工作电压窗口和15.9 W时公斤的一个有吸引力的能量密度^-1处的175.0的功率密度钨千克^-1在两电极系统中。此外，它还具有出色的循环稳定性（98％，10000个循环）和良好的速率性能。整个过程是一种绿色，无氧化剂，无酸且低成本的方法，用于将绿色生物质转化为具有自然连通孔的自官能化碳，旨在制造绿色能源设备。所有吸引人的功能使环保路线成为制备其他多孔电活性材料的竞争者。