低灰低硅竹炭的制备及衍生硬炭的电化学性能

doi:10.11949/0438-1157.20241441

摘要/Abstract

摘要：

竹炭在储能等领域有巨大的应用潜力。然而，无机成分尤其是硅会严重影响其性能。采用KOH浸渍竹材、与竹材共炭化后酸洗脱除硅及其他无机组分，考察KOH浓度、浸渍时间、炭化温度对脱硅脱灰效果的影响；借助ICP-MS等方法表征脱灰效果、探究脱灰机理。此外，将竹炭制为硬炭，表征电化学性能。结果表明，KOH可有效负载到竹材上，竹材在3 mol·L^-1 KOH溶液中浸渍4 h，650℃下炭化后酸洗，竹炭灰分含量可降低至0.55%、脱灰率达84.76%，Si的含量降低至0.3%、脱硅率达76.19%；低灰竹炭制备硬炭的电化学性能显著优于未脱灰样品；50 mA·g^-1的电流密度下首次库仑效率达到70.67%；低灰竹基硬炭经过50 mA·g^-1~5 A·g^-1电流密度的循环后，在50 mA·g^-1下可逆比容量可恢复至365 mAh·g^-1。碱浸竹材炭化后酸洗是深度脱灰脱硅的有效途径，低灰竹基硬炭的电化学性能优异。

关键词: 生物质, 竹, 碱浸-炭化-酸洗, 脱灰, 二氧化硅, 硬炭, 电化学

Abstract:

Bamboo char, with its distinctive porous structure, offers significant potential for applications in adsorption and energy storage. However, bamboo is a silicon-rich plant. The inorganic components in bamboo carbon, especially Si, can seriously affect its performances. Therefore, it is of significance to develop an effective and cost-efficient approach for impurity removal. In this paper, an innovative method was presented to remove Si and other inorganic components from bamboo char, in which bamboo was impregnated by KOH, followed by co-carbonization of KOH and bamboo, and acid washing. The effects of KOH concentration, impregnation duration, and carbonization temperature on the removal efficiency of silicon and other inorganic components were systematically investigated using EDS and ICP-MS, and the mechanism of alkali impregnation-carbonization-acid washing was explored. In addition, hard carbon samples were prepared from bamboo char and low ash bamboo char, respectively, and their electrochemical properties were characterized. The results show that KOH can be effectively loaded onto bamboo. After the bamboo is immersed in 3 mol·L^-1 KOH solution for 4 h and carbonized at 650℃ and then acid-washed, the ash content of bamboo charcoal can be reduced to 0.55%, the deashing rate reaches 84.76%, the Si content is reduced to 0.3%, and the desiliconization rate reaches 76.19%. During carbonization, KOH reacts with silicon in bamboo to form acid-soluble silicates, which are effectively removed by acid washing. The electrochemical performance of hard carbon prepared from bamboo char with low ash and silicon contents is significantly better than that from un-deashed bamboo char samples. The initial coulombic efficiency reaches 70.67% at a current density of 50 mA·g^-1. After charging and discharging at a current density of 50 mA·g^-1—5 A·g^-1, the reversible specific capacity of the hard carbon prepared from low ash bamboo charcoal is still as high as 365 mAh·g^-1 when the current density is restored to 50 mA·g^-1. Acid washing of char from carbonization of alkali-impregnated bamboo is an effective approach for deep deashing and desilication. Hard carbon derived from bamboo char with low ash and silicon contents has excellent electrochemical performance.

Key words: biomass, bamboo, alkali impregnation-carbonization-acid washing, deashing, silica, hard carbon, electrochemistry

中图分类号:

TQ 15

张畅, 解强, 沙雨桐, 王炳杰, 梁鼎成, 刘金昌. 低灰低硅竹炭的制备及衍生硬炭的电化学性能[J]. 化工学报, 2025, 76(6): 3073-3083.

Chang ZHANG, Qiang XIE, Yutong SHA, Bingjie WANG, Dingcheng LIANG, Jinchang LIU. Preparation of bamboo char with low ash and silicon content and electrochemical properties of its derived hard carbon[J]. CIESC Journal, 2025, 76(6): 3073-3083.

图/表 12

表1 竹材及竹炭的工业分析指标

Table 1 Results of proximate analysis of bamboo and bamboo char samples

样品	水分(M_ad)/%	灰分(A_d)/%	挥发分(V_daf)/%	固定碳(FC_daf)/%
B	6.76	1.30	83.87	16.13
BC	1.24	3.61	11.88	88.12
HBC	1.3	2.73	10.11	89.89

图1 (a)竹材、竹炭及碱浸处理竹炭样品的灰分含量，(b)不同炭化温度竹炭样品无机组分含量

Fig.1 (a) The ash content of bamboo, bamboo char and bamboo char treated by alkali leaching, (b) The inorganic component content of bamboo char samples carbonized at different temperatures

图2 竹炭、酸洗竹炭及KOH浸渍处理竹炭样品元素含量

Fig.2 The element content of bamboo char, bamboo char after acid washing and bamboo char treated by KOH impregnation and acid washing

图3 竹炭、不同浓度KOH浸4 h竹炭及3 mol·L-1KOH浸不同时间竹炭样品的EDS图

Fig.3 EDS diagrams of bamboo char, bamboo char impregnated by KOH with different concentrations for 4 h and bamboo char impregnated in 3 mol·L-1 KOH for different time

图4 (a)竹炭及处理样品的红外光谱图，(b)不同温度炭化的竹炭灰分XRD图，(c)650℃炭化的竹炭灰分的XRD图

Fig.4 (a) Infrared spectra of bamboo char and treated samples, (b) XRD patterns of ash from bamboo char carbonized at different temperatures, (c) XRD patterns of ash from bamboo char carbonized at 650℃

表2 3mol·L-1KOH浸渍4 h处理竹材在不同温度下炭化得到竹炭的灰分XRF结果

Table 2 XRF analysis results of ashes of bamboo char samples obtained by carbonization of bamboo treated with 3 mol·L-1 KOH for 4 h at different temperatures

炭化温度/℃	元素含量/%
炭化温度/℃	K	O	Si	Na	Al	Mg	Ca
600	79.89	17.52	0.49	0.38	0.13	0.27	0.20
650	79.96	17.49	0.43	0.40	0.10	0.25	0.18
700	80.01	17.43	0.39	0.45	0.09	0.24	0.17
750	78.10	18.02	1.43	0.51	0.23	0.20	0.22
800	73.41	20.51	3.82	0.63	0.48	0.14	0.39

图5 BC-0-0-600-1300及HBC-3-4-650-1300的热重曲线(a)、XRD图(b)、拉曼图(c)、孔径分布(d）

Fig.5 BC-0-0-600-1300 and HBC-3-4-650-1300 Thermogravimetric diagram (a), XRD spectrum (b), Raman spectrum (c), and pore size distribution diagram (d)

图6 竹基硬炭样品的透射电镜图

Fig.6 TEM diagram of bamboo based hard carbon samples

图7 BC-0-0-600-1300和HBC-3-4-650-1300的（a）、（b）充放电图（c）、（d）交流阻抗图（e）、（f）倍率图

Fig.7 BC-0-0-600-1300 and HBC-3-4-650-1300 the initial galvanostatic charge-discharge profiles[(a), (b)]; AC impedance diagram[(c), (d)]; rate diagram[(e), (f)]

表3 未脱硅竹基硬炭和低灰低硅竹基硬炭电化学性能及孔结构比较

Table 3 Comparison of bamboo-based hard carbon and low ash bamboo-based hard carbon

样品

可逆比容量/(mAh·g^-1)

首次库仑

效率/%

图8 BC-0-0-600-1300及HBC-3-4-650-1300的XPS图

Fig.8 XPS spectra of BC-0-0-600-1300 and HBC-3-4-650-1300

表4 HBC-3-4-650-1300与其他竹基硬炭的电化学性能比较

Table 4 The electrochemical performances of HBC-3-4-650-1300 compare with other bamboo-based hard carbons

样品或文献	首次库伦效率/%	首次放电比容量/(mAh·g^-1)	充放电循环性能/(mAh·g^-1)
HBC-3-4-650-1300	70.67	536.9	348.5
[32]	84.1	414.3	295.9
[31]	83.7	363.2	272.8
[33]	84.4	378.8	283.9

参考文献 33

[1]	Kressman R, Long S. GCB‐Bioenergy reaches a new high in impact factor and goes open access[J]. GCB Bioenergy, 2016, 8(1): 936-953.
[2]	Park S, Song J J, Lee W C, et al. Advances in biomass-derived electrode materials for energy storage and circular carbon economy[J]. Chemical Engineering Journal, 2023, 470: 144234.
[3]	Yang X M, He H H, Lv T, et al. Fabrication of biomass-based functional carbon materials for energy conversion and storage[J]. Materials Science and Engineering R: Reports, 2023, 154: 100736.
[4]	Ashok Kumar S S, Bashir S, Pershaanaa M, et al. A review on the recent progress of the plant-based porous carbon materials as electrodes for high-performance supercapacitors[J]. Journal of Materials Science, 2023, 58(15): 6516-6555.
[5]	Zhang G X, Chen Y M, Chen Y G, et al. Activated biomass carbon made from bamboo as electrode material for supercapacitors[J]. Materials Research Bulletin, 2018, 102: 391-398.
[6]	Chai Y L, Wan C C, Cheng W J, et al. Biomass-derived carbon for dye-sensitized solar cells: a review[J]. Journal of Materials Science, 2023, 58(14): 6057-6075.
[7]	Du B X, Xing J W, Ran Z Y, et al. Dielectric and energy storage properties of polypropylene by deashing method for DC polymer film capacitors[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2021, 28(6): 1917-1924.
[8]	Liou T H, Wu S J. Characteristics of microporous/mesoporous carbons prepared from rice husk under base- and acid-treated conditions[J]. Journal of Hazardous Materials, 2009, 171(1/2/3): 693-703.
[9]	Zhou S Y, Li X H, Wang Z X, et al. Effect of activated carbon and electrolyte on properties of supercapacitor[J]. Transactions of Nonferrous Metals Society of China, 2007, 17(6): 1328-1333.
[10]	Zhang Y F, Zhang C X, Huang G X, et al. Tailoring the textural properties of hierarchical porous carbons for supercapacitors[J]. Materials Letters, 2015, 159: 377-380.
[11]	Yang X M, Lv T, Qiu J S. High mass‐loading biomass‐based porous carbon electrodes for supercapacitors: review and perspectives[J]. Small, 2023, 19(22): 2300336.
[12]	Gou L, Jing W F, Li Y, et al. Lattice-coupled Si/MXene confined by hard carbon for fast sodium-ion conduction[J]. ACS Applied Energy Materials, 2021, 4(7): 7268-7277.
[13]	Dong D, Xiao Y. Recent progress and challenges in coal-derived porous carbon for supercapacitor applications[J]. Chemical Engineering Journal, 2023, 470: 144441.
[14]	Kharrazi S M, Soleimani M, Jokar M, et al. Pretreatment of lignocellulosic waste as a precursor for synthesis of high porous activated carbon and its application for Pb (Ⅱ) and Cr (Ⅵ) adsorption from aqueous solutions[J]. International Journal of Biological Macromolecules, 2021, 180: 299-310.
[15]	Chen D Y, Zhuang X Z, Gan Z Y, et al. Co-pyrolysis of light bio-oil leached bamboo and heavy bio-oil: effects of mass ratio, pyrolysis temperature, and residence time on the biochar[J]. Chemical Engineering Journal, 2022, 437: 135253.
[16]	张振, 杨胜杰, 张晓丽, 等. 超级电容器用竹基活性炭原料脱灰工艺的研究[J]. 电池工业, 2013, 18(1): 55-57.
	Zhang Z, Yang S J, Zhang X L,et al. Research on the deashing technology for super capacitor using bamboo-based activated carbon material[J]. Chinese Battery Industry, 2013, 18(1): 55-57.
[17]	Yang J F, Feng Z X, Gao Q, et al. Ash thermochemical behaviors of bamboo lignin from kraft pulping: influence of washing process[J]. Renewable Energy, 2021, 174: 178-187.
[18]	Liu X, Tang X, Ran H, et al. Si supply could alter N uptake and assimilation of saplings—A 15N tracer study of four subtropical species[J] Forests, 2023, 14: 1353.
[19]	Yang W T, Gong X X, Ji H B, et al. Qualitative and quantitative characterization of nutrient content and morphology in seeds of bamboo, rice, and wheat[J]. Journal of Cereal Science, 2021, 101: 103273.
[20]	Rusch F, Wastowski A D, De Lira T S, et al. Description of the component properties of species of bamboo: a review[J]. Yordsre, 2023, 13(3): 2487-2495.
[21]	Gao Q, Ni L M, He Y Y, et al. Effect of hydrothermal pretreatment on deashing and pyrolysis characteristics of bamboo shoot shells[J]. Energy, 2022, 247: 123510.
[22]	Zhang J B, Zhong Z P, Shen D K, et al. Preparation of bamboo-based activated carbon and its application in direct carbon fuel cells[J]. Energy & Fuels, 2011, 25(5): 2187-2193.
[23]	Ellerbrock R, Stein M, Schaller J. Comparing amorphous silica, short-range-ordered silicates and silicic acid species by FTIR[J]. Scientific Reports, 2022, 12(1): 11708.
[24]	Su M F, Ni L M, Rong S W, et al. The ash-forming element migration and mineral transformation during the bamboo combustion process[J]. ACS Omega, 2024, 9(20): 21974-21982.
[25]	Zheng H, Wang Z Y, Deng X, et al. Characteristics and nutrient values of biochars produced from giant reed at different temperatures[J]. Bioresource Technology, 2013, 130: 463-471.
[26]	Liu L, Tan Z, Gong H, et al. Migration and transformation mechanisms of nutrient elements (N, P, K) within biochar in straw-biochar-soil-plant systems: a review[J]. 2019, 7: 22-32.
[27]	Zhang X W, Deng H K, Yang J, et al. Isoconversional kinetics of pyrolysis of vaporthermally carbonized bamboo[J]. Renewable Energy, 2020, 149: 701-707.
[28]	Pothaya S, Poochai C, Tammanoon N, et al. Bamboo-derived hard carbon/carbon nanotube composites as anode material for long-life sodium-ion batteries with high charge/discharge capacities[J]. Rare Metals, 2024, 43(1): 124-137.
[29]	Chen L, Bai L, Yeo J, et al. Wood-derived carbon with selectively introduced C O groups toward stable and high capacity anodes for sodium storage[J]. ACS Appl. Mater. Interfaces, 2020, 12: 27499-27507.
[30]	Sun D, Zhao L, Sun P, et al. Rationally regulating closed pore structures by pitch coating to boost sodium storage performance of hard carbon in low‐voltage platforms[J]. Advanced Functional Materials, 2024, 34(40): 2403642.
[31]	Kuai J, Xie J, Wang J D, et al. Comparison and optimization of biomass-derived hard carbon as anode materials for sodium-ion batteries[J]. Chemical Physics Letters, 2024, 842: 141214.
[32]	Xu T Y, Qiu X, Zhang X, et al. Regulation of surface oxygen functional groups and pore structure of bamboo-derived hard carbon for enhanced sodium storage performance[J]. Chemical Engineering Journal, 2023, 452: 139514.
[33]	Kuai J, Xie J, Wang J D, et al. Optimizing hard carbon materials for sodium-ion batteries: insights from particle size and soft carbon-coating strategy[J]. Journal of Power Sources, 2025, 627: 235792.