Abstract:

Spent mushroom substrate has rich wood fiber matrix with loose and porous texture as well as mycelium protein, which brings an innate advantage to be used for the preparation of high-performance biomass-based porous carbon, and thus can also yield considerable ecological and economic benefits. Three-dimensional (3D) hierarchical porous carbon with high nitrogen-doping (7.78%) was prepared from spent culture substrate of white fungus by pretreatment with a mixture of NaOH/urea (mass ratio 7∶12) aqueous solution followed by high-temperature carbonization. The pore structure analysis results showed that the sample of BC-5-800 had a high specific surface area of 1568m²/g and total pore volume of 1.53cm³/g with mesoporosity up to 83%. With BC-5-800 as the working electrode, a high specific capacitance of 278F/g at 0.5A/g was recorded in a three-electrode test system and it could still maintained at 230F/g under 10A/g. When tested in two-electrode device, the energy density of BC-5-800 reached 5.83Wh/kg with power density as high as 6990W/kg, and the capacitance retention rate after 10000 charge-discharge cycles was 87%, showing excellent cyclic stability. This study paves a new way for the possible high-value reutilization of spent culture substrate of edible fungus.

Key words: spent culture substrate of white fungus, sodium hydroxide (NaOH)/urea, nitrogen-doping, 3D hierarchical porous carbon, electrode material

摘要：

食用菌菌糠富含疏松多孔的木质纤维基质和菌丝残体蛋白，将其用于高性能生物质基多孔炭的制备具有先天优势，亦能产生可观的生态和经济效益。本文以银耳菌糠为原料，利用NaOH/尿素（质量比为7∶12）水溶液体系进行冻融预处理后，经高温热解炭化制备获得高氮掺杂量（7.78%）的三维（3D）多级孔炭材料。孔结构分析结果显示样品BC-5-800的比表面积可达1568m²/g，孔容为1.53cm³/g且中孔率高达83%。以BC-5-800为工作电极，在三电极测试体系中，当电流密度为0.5A/g时，测得的比电容为278F/g，且在10A/g下仍能保持230F/g的比电容；在两电极装置中，当功率密度高达6990W/kg时，能量密度达到5.83Wh/kg，且经10000次循环充放电后的电容保持率为87%，呈现出优异的循环稳定性。本研究为食用菌菌糠的高值化回收再利用提供了新思路。

关键词: 银耳菌糠, 氢氧化钠/尿素, 氮掺杂, 3D多级孔炭, 电极材料