Next Article in Journal
Revealing Enhanced Optical Modulation and Coloration Efficiency in Nanogranular WO3 Thin Films Through Precursor Concentration Modifications
Previous Article in Journal
The Influence of the Degree of Tension and Compression of Copper on the Indentation Size Effect (ISE)
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Crystals
Volume 14
Issue 11
10.3390/cryst14110914
crystals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Comparative Analysis of Graphitization Characteristics in Bamboo and Oak Charcoals for Secondary Battery Anodes

by
Kiseon Lee
1,
Seung-Kon Ryu
2,
Hong-Gun Kim
1,2,
Lee-Ku Kwac
1,2 and
Young-Soon Kim
2,*
1
Department of Carbon Convergence Engineering, Jeonju University, Jeonju 55069, Republic of Korea
2
Institute of Carbon Technology, Jeonju University, Jeonju 55069, Republic of Korea
*
Author to whom correspondence should be addressed.
Crystals 2024, 14(11), 914; https://doi.org/10.3390/cryst14110914
Submission received: 9 October 2024 / Revised: 20 October 2024 / Accepted: 21 October 2024 / Published: 23 October 2024
Browse Figures
Versions Notes

Abstract

:
When compared to natural graphite, artificial graphite has advantages such a longer cycle life, faster charging rates, and better performance. However, the process of producing it, which frequently uses coal, raises questions about the impact on the environment and the depletion of resources. Eco-friendly, wood-based graphite must be developed in order to solve these problems. This study assessed and investigated the characteristics of charcoals derived from bamboo and oak which were utilized to produce graphite. After heating to 1500 °C at 10 K/min, 86.87 wt% of oak charcoal and 88.33 wt% of bamboo charcoal remained, indicating a yield of more than 85% when charcoal was graphitized. Depending on the species of wood, different-sized pores showed different shapes as the graphitization process advanced, as revealed by SEM surface analyses. The carbon atoms seen in the XRD crystal development changed into graphite crystals when heated to 2400 °C, and the isotropic peaks vanished. Bamboo charcoal has a higher degree of crystallinity than other wood-based charcoals, such as oak charcoal, which is made up of turbostratic graphite, according to Raman spectroscopic research. Lithium-ion batteries employ bamboo charcoal as their anode material. At this point, the values for soft carbon were determined to be 196 mAh/g and for hard carbon to be 168 mAh/g at a current density of 0.02 A/g.

1. Introduction

Nowadays, fossil fuels are a common source of energy but are not sustainable and contribute to environmental issues like global warming. A sustainable and environmentally friendly energy source is wood-derived charcoal [1]. Worldwide, a variety of traditional kiln types are used to manufacture charcoal, which is created through the carbonization of biomass [2]. Furthermore, it is widely utilized in fields relating to agriculture and livestock husbandry and is environmentally friendly. It also enhances the physical characteristics of soil, encourages the growth of microorganisms that are beneficial to plant growth, and boosts soil vitality [3]. Because of its exceptional electrical conductivity, numerous vertically aligned microchannels, distinctive porous structure, chemical and mechanical stability, and adjustable multifunctionality, biomass-based charcoal has garnered a lot of interest and attention [4].
Because of this, numerous researchers have published papers on the production of graphite through high-temperature heating of wood charcoal. The word “graphite” comes from the Greek word “grapho”, which means “to write” [5]. It can be broadly classified into two categories: artificial graphite, which is made artificially, and natural graphite, which is mined and utilized in mines. Artificial graphite has the advantages of tight controllability of the synthesis process, a big carbon source, and high purity, while natural graphite is more costly, requires a challenging refining procedure, and has inconsistent purity [6]. The drawback is that it must be produced by heat treating organic materials like coal or coke at temperatures higher than 2500 °C [7].
Because of its layered structure, which facilitates easy lithium-ion movement, graphite is currently the most extensively utilized anode material in lithium-ion batteries. Although natural graphite offers a large storage capacity, its short cycle life and low initial charge–discharge efficiency are drawbacks [8]. However, compared to natural graphite, artificial graphite is more expensive and has a relatively small storage capacity. On the other hand, it has a long cycle life, great charging speed, and output [9]. Methods such coating natural graphite [10], manufacturing carbon nanotubes with a catalyst [11], and carbonizing biomass [12] are examples of active research efforts aimed at addressing these negative aspects.
High storage capacity and exceptional rate performance for lithium-ion batteries were achieved by Lu et al. by the fabrication of high-performance ultrathin LiCoO2 cathodes using a straightforward sol–gel method followed by a sintering procedure [13]. Wood-based carbon modified by a two-step ion exchange method, followed by carbonization and acid washing, showed exceptional performance in Zn-ion hybrid supercapacitors and all-solid-state supercapacitors, according to Song et al.’s paper [14]. Min et al. consistently incorporated CoP nanoparticles into the channels of carbonized wood membrane to create a very stable and effective self-supporting H2 evolution anode in both acidic and alkaline circumstances [15]. Through the pyrolysis of CoFe Prussian blue analog/wood precursor, Ao et al. effectively fused CoFe alloy encased in nitrogen-doped carbon nanocages, and showed outstanding catalytic activity for the oxygen redox reaction in a Zn-air battery [16]. Mangrove roots that had developed a pore structure and adequate conductivity were carbonized by Wood et al. and utilized as an electrode in capacitive deionization (CDI) systems [17].
The study was carried out by the research team, with a special emphasis on the physiological traits that set bamboo apart. Bamboo grows new stems from its roots in order to reproduce, and both root and stem growth happen at the same time. These qualities enable bamboo to thrive in a variety of climatic settings and to be extremely adaptive to changes in the surrounding environment. Bamboo also has a short growth cycle; thus, it has the advantage of being able to provide resources in a short period of time [18,19]. It is also regarded as a sustainable resource due to its high carbon absorption capacity and little need for chemical pesticides and fertilizers during growing [20].
Based on the findings of a prior study that described the properties of oak charcoal when graphitized at 2400 °C, the research team set out to determine how the properties of traditional Korean charcoal changed when heat treated at high temperatures by graphitizing bamboo charcoal at 2400 °C. These benefits of bamboo demonstrate its sufficient potential as a sustainable energy source [21].

2. Materials and Methods

2.1. Materials

In order to obtain powder that passed through 32 μm < powder sample < 45 μm, the material for the experiment was oak charcoal that was produced in a traditional charcoal kiln in Sangdongeup, Taebaek-gun, Gangwon-do. The charcoal was then split into small pieces and ground using a ball mill (BML-2. DAIHAN Scientific, Wonju, Gangwon, Republic of Korea) and sieved using a standard sieve (standard sieve, ISO 3310.1 [22]). Furthermore, powdered bamboo charcoal was obtained from a traditional charcoal kiln in Damyang-eup, Damyang-gun, Jeollanamdo. After being sieved and dried at 120 °C for two hours, split powders of oak and bamboo were stored in a desiccator in preparation for the subsequent experiment. An anode slurry was prepared using a mixture of hard or soft carbon from bamboo, conductive carbon (Super P, Imerys Graphite & Carbon, Bironico, Ticino, Switzerland), and a polyvinylidene fluoride binder at a weight ratio of 8:1:1. After coating the mixtures onto aluminum foil, the coated film was dried at 100 °C for 12 h. The anode loading was 2.5 mg/cm2.

2.2. Methods

The high-temperature heat treatment was carried out in two stages, as Figure 1 illustrates. The first stage involved carbonization at various heat treatment temperatures up to 1500 °C in a nitrogen atmosphere. The second stage involved treating the graphite furnace with a high vacuum at 1500 °C to remove any remaining oxygen and gases. After that, the atmosphere was changed to argon, and graphitization was carried out for one hour at 1800 °C, thirty minutes at 2000 °C, and ten minutes at 2400 °C. In light of the heat treatment temperature (temp, °C) and time (time, min.), the samples were labeled as 1000/60, 1100/60, 1300/60, 1500/60, 1800/60, 2000/30, and 2400/10.

2.3. Characterization

Surface area analysis was carried out using Micromeritics (ASAP 2420, Norcross, GA, USA) utilizing physical adsorption of nitrogen gas for general evaluations of the samples utilized in the experiment. A Thermal Analyzer (Mettler-Toledo, TGA/DSC1, Columbus, OH, USA) was used to perform thermal analysis while heating materials to a temperature of 1500 °C in a nitrogen atmosphere. An Automatic Elemental Analyzer II (Thermo Fisher Scientific, FLASH 2000, Bedford, MA, USA) was used to assess elemental analysis and variations in the amount of fixed carbon. Using Scanning Electron Microscopy (SEM, (HITACHI, SU7000, Tokyo, Japan)), the sample’s altered surface morphology was examined for characteristic analysis. Transmission Electron Microscopy (TEM, FEI, TECNAI G2 F30, Hillsboro, OR, USA) was used to observe the internal crystal structure, and X-ray diffraction (XRD, Bruker, D8 ADVANCE, Karlsruhe, Germany) was utilized to quantify the temperature at which graphite crystals form. The degree of graphization for black powder was analyzed by Raman spectroscopy (Horiba, LabRAM HR-800, Kyoto, Japan).

3. Results and Discussion

3.1. Surface Area Analysis Based on Particle Size

Following the crushing and size sorting of oak charcoal, Table 1 shows the effects of charcoal powder size on specific surface area, micropore volume, average pore size, and pore volume. Following the crushing and size sorting of oak charcoal, Table 1 shows the effects of charcoal powder size on specific surface area, micropore volume, average pore size, and pore volume. After being divided into eight categories based on size—4.75 mm and up—and tested, the crushed charcoal had average sizes of 4.05 mm, 2.85 mm, 2.18 mm, 1.85 mm, 1.70 mm, 10 μm, and 4 μm.
When the particle size was greater than 4.75 mm, the specific surface area (ABET) measured was 13.80 m2/g. It was observed that the specific surface area increased as the particle size decreased. However, in powder sample B (4 μm), the specific surface area dropped to 412.49 m2/g, indicating that the relationship between specific surface area and particle size is not always inversely proportional. Furthermore, the specific surface area (ABET) behavior was found to be similar to that of the total volume (Vt), the average pore diameter (Dm), and the ratio of the micropore volume (Vmi) to the total volume (Vt). This demonstrates that the specific surface area, total volume, micropore volume ratio, and particle diameter are all significantly impacted by particle size. Specifically, as oak charcoal is ground into smaller particle sizes, the specific surface area increases dramatically, while the mesopores and macropores break down and disappear, resulting in a lower average pore size.
In their investigation into the moisture adsorption capabilities of charcoal, Kim et al. [23] noted that the gaps in the charcoal break down when it is ground into a powder, which increases the specific surface area and the quantity of adsorbate that can be desorbed at low relative pressure. Furthermore, An et al. [24] examined the properties of charcoal made in traditional Korean charcoal kilns and found that the specific surface area, total volume, micropores, and pore size differ based on the charcoal’s raw material and manufacturing company. Therefore, the characteristics of the charcoal by particle size should be taken into account to present quantitative characteristics of traditional Korean charcoal.
Accordingly, the specific surface area, total volume, micropore volume, and average particle diameter varied when the characteristics were analyzed by particle size. Therefore, in this experiment, particles with diameters ranging from 32 μm to 45 μm were used and heat treated at a high temperature, and then the results were examined.

3.2. Thermogravimetric Analysis

Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTG) data can be used to determine the evaporation temperatures of various non-carbon elements and compounds during the synthesis of graphite from charcoal. TGA can identify mass loss due to the evaporation of components such as oxygen, hydrogen, and other volatiles in the charcoal when it is heated during the graphitization process. The temperature at which this mass loss is most noticeable coincides with the DTG peak. The carbon combustion peak, which indicates the thermal stability of the carbon structure, can also be identified in TGA-DTG data. For instance, the temperature of maximum mass change (T_max) calculated from the TGA-DTG carbon combustion peak rises from graphene oxide (GO) at 558–616 °C to graphene at 659–713 °C, and, ultimately, to graphite at 841–949 °C, according to the research by Farivar et al. and Xie et al. [25,26].
The thermal analysis results of 3.32 m of powdered oak charcoal heated at 10 °C/min to about 1500 °C in a nitrogen environment are displayed in Figure 2. The figure indicates that, at room temperature, it includes an unknown adsorbent and a little quantity of moisture [27]. As a result, the weight started to decline at about 100 °C and decreased by 5.53 wt% by the time it reached around 200 °C. It dropped to 10.34 wt% at 1000 °C and 13.13 wt% at 1500 °C, leaving 86.87 wt% as the residual amount. Consequently, it was established that, after heating the white charcoal utilized in this investigation to room temperature at a steady rate up to 1500 °C, about 86% of the charcoal (residual amount) remained. The weight of the powdered bamboo charcoal was reduced by 11.67 weight percent, leaving 88.33 weight percent, which was marginally greater than the yield of 86.87 weight percent for oak charcoal. This demonstrates that a minimum of 86% of the product is produced using graphite.

3.3. Elemental Analysis

Table 2 shows the carbon, nitrogen, oxygen, hydrogen, and sulfer contents of charcoal samples made from oak and bamboo (32 μm < powder sample < 45 μm) that were heat treated for 60 min from 1000 to 1500 °C in a nitrogen environment and for varying amounts of time at 1800 to 2400 °C in an argon atmosphere. The C, O, H, and S contents obtained with bamboo and oak were compared using elemental analysis. However, not all samples showed the presence of S (sulfer). The powder made from the raw material (as received) was heat treated once more for 60 min at 1000 °C. The fixed carbon content was 92.12 wt%, which falls within the range of the six Indonesian bamboo species investigated by Park et al. (88.4 wt% to 95.7 wt%) [28]. This was significantly higher than the 79.36 wt% of oak charcoal produced at the same temperature [21].
According to the study by Hu et al. [29], the carbon content of bamboo heat treated at 800 °C was 89.55 wt%, the oxygen content was 8.21 wt%, and the nitrogen content was 1.06 wt%, which is a similar pattern to the present study. Figure 3 illustrates how heat treatment at 1300 °C for 60 min drastically altered the fixed carbon content of bamboo charcoal. However, starting at 1500 °C, it began to rise significantly, and, by 2000 °C, graphitization was fully achieved. In the case of oak charcoal, the fixed carbon content increased dramatically first at 1100 °C for 60 min, and then again at 1500 °C. Complete graphitization also occurred at 2000 °C. Furthermore, it is evident that bamboo outperforms oak in terms of carbon yield at temperatures below 1500 °C, whereas oak outperforms bamboo in terms of carbon yield at temperatures above 1500 °C.

3.4. Surface Morphology

SEM pictures of samples prepared using various heat treatment temperatures and durations—up to 2400 °C—for bamboo and oak charcoal are shown in Figure 4. Both images (Figure 4A,C) show the results of a 60 min heat treatment at 1800 °C, exhibiting average pore diameters of ~10 µm and ~20 µm, respectively. As shown in Figure 4B, the oak sample was finely broken and showed no pores after heat treatment at 2400 °C for 10 min. In contrast, Figure 4D reveals that the bamboo sample’s pores became smaller, and the pore walls thickened and plugged. This shape was also reported in the SEM images observed by Fromm et al. [30] after carbonizing bamboo at 2800 °C and in the SEM images observed by Su et al. [31] after carbonizing bamboo in a 900 W microwave device. This makes it evident that the pores close up and the graphitization of oak increases as it proceeds. Because bamboo’s tissue is denser than oak’s and does not break even at high temperatures, when it graphitizes, its special porous structure is preserved and causes blocked pores.

3.5. TEM Observation of Internal Structure

In Figure 5, both images A and B exhibit asymmetrically produced graphite layers, formed after heat treating oak and bamboo charcoal for 60 min at 1800 °C. The heat-treated charcoals in pictures C and D were exposed to a temperature of 2000 °C for 30 min. Graphite layers are created more clearly at this temperature than at 1800 °C, and certain graphite layers exhibit directionality. Pictures E and F show that the bamboo and oak charcoals have fully graphitized with a turbostratic layer structure after being heat treated for ten minutes at 2400 °C. The average graphite interlayer distance was determined by enlarging images E and F to obtain images G and H. As can be seen, the interlayer distances of bamboo and oak charcoal are 0.341 and 0.340 nm, respectively. This suggests that, after being heat treated to 2400 °C, the interlayer distances of the two types of charcoal become approximately similar. The findings of Hata et al. [32], Takeshi et al. [33], and Kawamura et al. [34] are in agreement with these ones. They are similar to the value of 0.336 nm reported by Hata et al. [35], who examined the inner 002 diffraction ring spacing after graphitizing charcoal at 2000 °C.

3.6. Crystal Growth by XRD

Using XRD to examine the internal structural properties of oak and bamboo charcoal, it was found that samples prior to heat treatment had a large diffraction peak around ~23° of 2θ up to 1500 °C. This suggests that the carbon atoms are amorphous carbon and have not solidified into graphite. On the other hand, a distinct hexagonal (H) graphite crystal peak emerged at around ~26° of 2θ in samples that underwent heat treatment at 1800 °C or more, suggesting that the carbon atoms in the char are transformed into graphite crystals. Furthermore, until 2000 °C, the carbon isotropic peak displayed a maximum instead of the (002) plane, and isotropic peaks emerged between the (002) and (100) planes, indicating the presence of a turbostratic structure in the crystalline planes (002) and (100) [36]. This indicates that the sample that was heated contained fine crystal lattices that were disordered structures with uneven orientations. Figure 6 shows the XRD spectra of white charcoal made from bamboo and oak [21] that has been heat treated to 2400 °C. The carbon isotope peaks in the oak and bamboo samples, which were visible until 2000 °C, disappear at 2400 °C. Additionally, plane (002) has a sharp maximum peak at 25.86° of 2θ, while plane (100) displays a peak at 43.12° of 2θ. Inagaki et al. [37] reported that, when pressurized at 500 MPa, a peak appeared at 2θ = 26.5° over 1600 °C, indicating that pressurization during high-temperature treatment promotes graphitization. Yamane et al. [33] carbonized cedar at 700 °C for 30 min to make charcoal and then heated it to 1770 °C while pressurizing at 49 MPa, a peak appeared around 2θ = 26.5°. In addition, Nishimiya et al. [38] reported that, when 30 wt% aluminum was used as a catalyst for graphitization of Japanese cedar charcoal, the graphitization temperature could be lowered to 1750 °C. This demonstrates that carbon atoms in the oak and bamboo samples were transformed into graphite crystals upon heat treatment at 2400 °C.

3.7. Analysis of Crystallinity by Raman Spectroscopy

The results of the Raman spectroscopy investigation of bamboo and oak charcoal following graphitization are shown in Figure 7. A clear 2D band forms after 10 min of heat treatment at 2400 °C for bamboo and oak charcoal, signifying the conversion of the charcoal to graphite crystals. Furthermore, the bamboo charcoal exhibits a distinct G band that distinguishes it from oak charcoal, while the oak charcoal’s D band is clearly visible.
According to Knight et al. [39], the irregular structure is associated with the D band at 1360 cm−1. The integrated intensity ratio, or ID/IG, of the D peak to the G peak is a valuable tool for determining the irregularity or particle size of irregular carbon materials. According to Ramirez-Rico et al. [40], Equation (1) can be used to determine the crystallinity (β) of carbon materials.
β = I G / ( I G + I D )
The areas beneath the G (1580 cm−1) and D (1360 cm−1) bands are used to compute IG and ID in Equation (1).
In Table 3, the graphite layer is shown to have a significantly more stable layered structure because, in contrast to 1800 °C, the peak of the G band is higher at 2400 °C than the peak of the D band. Nevertheless, it is evident that it has transformed into disorganized graphite carbon rather than whole graphite crystals. The full width at half maximum intensity (G-FWHM) in the Raman spectra of carbon-based materials was defined by Yoshida et al. [41] as a qualitative indicator of graphitization. Graphite crystals have a layer spacing of 0.3374 nm < d002 < 0.3421 nm, whereas carbon compounds pyrolyzed at 2600 °C for 5 h had layer spacing of 0.3367 nm < d002 < 0.3421 nm.
The layered structure of the charcoal in this study caused the layer spacing to be larger than that of ideal graphite, measuring 0.3364 nm < d002 < 0.3441 nm, as determined by the G band after the charcoal was graphitized at 2400 °C for 10 min. Table 3 indicates that, overall, the bamboo charcoal samples had more crystallinity than the oak charcoal samples. In particular, the bamboo charcoal heat treated at 2400 °C for 10 min had a crystallinity (β) of 0.92, which was much higher than the oak charcoal’s (0.55). Furthermore, Yu et al. [42] observed that beech charcoal, when graphitized at 2400 °C for 10 min, has a crystallinity of 0.49, which is comparable to oak charcoal. This indicates that bamboo charcoal has a higher degree of crystallinity than oak or chestnut charcoal. Moreover, it is clear that perfect, regular graphite crystals cannot be obtained, not even when charcoal is graphitized.

3.8. Utilization of Anode Materials for Lithium-Ion Batteries

As a result of analyzing the crystallinity by Raman spectroscopy, bamboo charcoal showed superior crystallinity compared to oak charcoal. Therefore, bamboo charcoal was chosen as an anode material for lithium-ion batteries. Hard carbon and soft carbon were made and tested using bamboo charcoal samples heat treated at 1800 °C and 2000 °C, respectively. By developing an anode material with 10% conductive carbon (Super P) added to 80% of the bamboo charcoal sample to increase conductivity and 10% PVDF binder to improve cohesion between materials and improve electrochemical stability, thermal stability, and affinity for the electrolyte, the potential applications of hard and soft carbon anodes were investigated. Polypropylene (Celgard 2400, Celgard LLC., Charlotte, NC, USA) was used as the separator, and 1.0 M LiPF6 with a 1:1 ratio of EC:DMC was used as the electrolyte. The current density was varied from 0.02 A/g to 20 A/g, and measurements were made over a potential window of 0.01 to 3.0 V. As seen in Figure 8A, we evaluated the rate capacity of both soft and hard carbon by increasing the current density every five cycles. At each fifth cycle, as illustrated in Figure 8B, hard carbon demonstrated specific discharge capacities of 160, 135, 105, 76, and 15 mAh/g at current densities of 0.1, 0.2, 0.5, 2, and 10 A/g, respectively. Soft carbon demonstrated specific discharge capacities of 125, 100, 90, 60, and 10 mAh/g at each fifth cycle, as indicated in Figure 8C, for current densities of 0.1, 0.2, 0.5, 2, and 10 A/g, respectively. The test results showed that the hard carbon achieved 168 mAh/g at a current density of 0.02 A/g, while the soft carbon achieved 196 mAh/g. Both samples showed similar performance as the current density increased.
According to Togonon et al. [43], at a current density of 0.02 A/g, hard carbon has a capacity of 270 mAh/g and soft carbon has a capacity of 330 mAh/g. Commercial graphite, on the other hand, has a capacity of about 360 mAh/g [44]. According to our research, hard carbon has poor storing capacity. However, considering its affordability and advantages over other carbon materials derived from wood-based charcoal, it exhibits significant promise as an anode material for lithium-ion batteries. As a result, bamboo charcoal has been considered to be a feasible anode for secondary batteries, though further research is required to improve its capability performance.

4. Conclusions

After heat treating oak and bamboo charcoal to 2400 °C and utilizing them in lithium secondary batteries, the properties of the charcoals were examined. The findings were as follows:
  • When charcoal is crushed to reduce particle size, the specific surface area increases significantly, and the mesopores and macropores break down and disappear, reducing the average pore size. As the particle size decreases through the crushing process, the surface-area-to-volume ratio increases, providing more surface area for the same volume. However, when the particle size falls below a certain threshold, the surface area no longer increases but decreases.
  • When oak and bamboo charcoal powders were heated to about 1500 °C at 10 K/min in a nitrogen atmosphere, thermal analysis results showed that 86.87 wt% of oak charcoal and 88.33 wt% of bamboo charcoal remained. This indicates that a yield of over 85% can be obtained when charcoal is graphitized.
  • SEM examination of the surface shape revealed that 10~20 µm of the average pore size breaks down or becomes blocked and disappears as graphitization progresses. TEM observation shows that graphitization occurs in the form of a turbostratic structure.
  • XRD analysis indicates that isotropic peaks disappear and carbon atoms are converted to graphite crystals when heat treated at 2400 °C. Raman spectroscopy analysis shows that bamboo charcoal has superior crystallinity compared to other wood-based charcoals such as oak charcoal.
  • Bamboo charcoal was used as an anode material for lithium-ion batteries. It was confirmed that hard carbon achieved 168 mAh/g at a current density of 0.02 A/g, and soft carbon achieved 196 mAh/g.

Author Contributions

Conceptualization, K.L. and S.-K.R.; methodology, K.L., H.-G.K., L.-K.K. and S.-K.R.; software, K.L. and Y.-S.K.; formal analysis, K.L., S.-K.R. and Y.-S.K.; investigation and data curation, K.L., H.-G.K., L.-K.K., S.-K.R. and Y.-S.K.; writing—original draft preparation, K.L. and Y.-S.K.; writing—review and editing, K.L. and Y.-S.K.; supervision, H.-G.K. and Y.-S.K.; project administration, H.-G.K.; funding acquisition, H.-G.K. All authors have read and agreed to the published version of the manuscript.

Funding

The research work described in this article was a part of the basic research project (no. 2016R1A6A1A03012069) supported by the National Research Foundation (Ministry of Education). This work also supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MIST) (no. 2020R1A2C1102174).

Data Availability Statement

The data presented in the paper are available upon request.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Kim, Y.S.; Hanif, M.A.; Song, H.; Kim, S.; Cho, Y.; Ryu, S.K.; Kim, H.G. Wood-Derived Graphite: A Sustainable and Cost-Effective Material for the Wide Range of Industrial Applications. Crystals 2024, 14, 309. [Google Scholar] [CrossRef]
  2. Chidumayo, E.N.; Gumbo, D.J. The environmental impacts of charcoal production in tropical ecosystems of the world: A synthesis. Energy Sustain. Dev. 2013, 17, 86–94. [Google Scholar] [CrossRef]
  3. Hunt, J.; DuPonte, M.; Sato, D.; Kawabata, A. The basics of biochar: A natural soil amendment. Soil Crop Manag. 2010, 30, 1–6. [Google Scholar]
  4. Zuo, Y.; Feng, J.; Soyol-Erdene, T.O.; Wei, Z.; Hu, T.; Zhang, Y.; Tang, W. Recent advances in wood-derived monolithic carbon materials: Synthesis approaches, modification methods and environmental applications. Chem. Eng. J. 2023, 463, 142332. [Google Scholar] [CrossRef]
  5. Sengupta, R.; Bhattacharya, M.; Bandyopadhyay, S.; Bhowmick, A.K. A review on the mechanical and electrical properties of graphite and modified graphite reinforced polymer composites. Prog. Polym. Sci. 2011, 36, 638–670. [Google Scholar] [CrossRef]
  6. Wang, Y.M.; Zhang, C.H. Study on structural evolution of synthetic graphite derived from lignite prepared by high temperature–high pressure method. Crystals 2022, 12, 464. [Google Scholar] [CrossRef]
  7. Lee, S.M.; Kang, D.S.; Roh, J.S. Bulk graphite: Materials and manufacturing process. Carbon Lett. 2015, 16, 135–146. [Google Scholar] [CrossRef]
  8. Zhao, W.; Zhao, C.; Wu, H.; Li, L.; Zhang, C. Progress, challenge and perspective of graphite-based anode materials for lithium batteries: A review. J. Energy Storage 2024, 81, 110409. [Google Scholar] [CrossRef]
  9. Fan, C.L.; Chen, H. Preparation, structure, and electrochemical performance of anodes from artificial graphite scrap for lithium ion batteries. J. Mater. Sci. 2011, 46, 2140–2147. [Google Scholar] [CrossRef]
  10. Zhao, H.; Ren, J.; He, X.; Li, J.; Jiang, C.; Wan, C. Modification of natural graphite for lithium ion batteries. Solid State Sci. 2008, 10, 612–617. [Google Scholar] [CrossRef]
  11. Shchegolkov, A.V.; Komarov, F.F.; Lipkin, M.S.; Milchanin, O.V.; Parfimovich, I.D.; Shchegolkov, A.V.; Semenkova, A.V.; Velichko, A.V.; Chebotov, A.V.; Nokhaeva, V.A. Synthesis and study of cathode materials based on carbon nanotubes for lithium-ion batteries. Inorg. Mater. Appl. Res. 2021, 12, 1281–1287. [Google Scholar] [CrossRef]
  12. Kamal, A.S.; Othman, R.; Jabarullah, N.H. Preparation and synthesis of synthetic graphite from biomass waste: A review. Syst. Rev. Pharm. 2020, 11, 881–894. [Google Scholar]
  13. Lu, L.L.; Lu, Y.Y.; Xiao, Z.J.; Zhang, T.W.; Zhou, F.; Ma, T.; Ni, Y.; Yao, H.B.; Yu, S.H.; Cui, Y. Wood-inspired high-performance ultrathick bulk battery electrodes. Adv. Mater. 2018, 30, 1706745. [Google Scholar] [CrossRef]
  14. Song, P.; Chen, C.; Shen, X.; Zeng, S.; Premlatha, S.; Ji, Z.; Zhai, L.; Yuan, A.; Liu, Q. Metal-organic frameworks-derived carbon modified wood carbon monoliths as three-dimensional self-supported electrodes with boosted electrochemical energy storage performance. J. Colloid Interface Sci. 2022, 620, 376–387. [Google Scholar] [CrossRef]
  15. Min, S.; Deng, W.; Li, Y.; Wang, F.; Zhang, Z. Self-Supported CoP Nanoparticle-Embedded Wood-Derived Porous Carbon Membrane for Efficient H2 Evolution in Both Acidic and Basic Solutions. ChemCatChem 2020, 12, 3929–3936. [Google Scholar] [CrossRef]
  16. Ao, K.; Zhang, X.; Nazmutdinov, R.R.; Wang, D.; Shi, J.; Yue, X.; Sun, J.; Schmickler, W.; Daoud, W.A. Hierarchical CoFe@ N-Doped Carbon Decorated Wood Carbon as Bifunctional Cathode in Wearable Zn-Air Battery. Energy Environ. Mater. 2024, 7, e12499. [Google Scholar] [CrossRef]
  17. Wood, A.R.; Garg, R.; Justus, K.; Cohen-Karni, T.; LeDuc, P.; Russell, A.J. Intact mangrove root electrodes for desalination. RSC Adv. 2019, 9, 4735–4743. [Google Scholar] [CrossRef]
  18. Liese, W.; Kohl, M. Bamboo: The Plant and Its Uses; Springer: Cham, Switzerland, 2015. [Google Scholar]
  19. Buziquia, S.T.; Lopes, P.V.F.; Almeida, A.K.; de Almeida, I.K. Impacts of bamboo spreading: A review. Biodivers. Conserv. 2019, 28, 3695–3711. [Google Scholar] [CrossRef]
  20. Iroegbu, A.O.C.; Ray, S.S. Bamboos: From Bioresource to Sustainable Materials and Chemicals. Sustainability 2021, 13, 12200. [Google Scholar] [CrossRef]
  21. Park, Y.N.; Lee, J.J.; Kwac, L.K.; Ryu, S.K.; Kim, H.G. Graphitization of Oak-Tree-Based White Charcoals by High Temperature Heat Treatment. Korean J. Chem. Eng. 2024, 41, 1841–1849. [Google Scholar] [CrossRef]
  22. ISO 3310-1; Test Sieves—Technical Requirements and Testing—Part 1: Test Sieves of Metal Wire Cloth. International Organization for Standardization: Geneva, Switzerland, 2016.
  23. Kim, D.W.; An, K.S.; Kwak, L.K.; Kim, H.G.; Ryu, S.K.; Lee, Y.S. A Study on Moisture Adsorption Capacity by Charcoals. Korean Chem. Eng. Res. 2022, 60, 377–385. [Google Scholar]
  24. An, K.S.; Kwak, L.K.; Kim, H.G.; Ryu, S.K. Characterization of Charcoals prepared by Korean Traditional Kiln. Korean Chem. Eng. Res. 2022, 60, 208–216. [Google Scholar]
  25. Farivar, F.; Yap, P.L.; Karunagaran, R.U.; Losic, D. Thermogravimetric analysis (TGA) of graphene materials: Effect of particle size of graphene, graphene oxide and graphite on thermal parameters. C 2021, 7, 41. [Google Scholar] [CrossRef]
  26. Xie, M.; Chen, W.; Xu, Z.; Zheng, S.; Zhu, D. Adsorption of sulfonamides to demineralized pine wood biochars prepared under different thermochemical conditions. Environ. Pollut. 2014, 186, 187–194. [Google Scholar] [CrossRef]
  27. Collard, F.X.; Blin, J. A review on pyrolysis of biomass constituents: Mechanisms and composition of the products obtained from the conversion of cellulose, hemicelluloses and lignin. Renew. Sustain. Energy Rev. 2014, 38, 594–608. [Google Scholar] [CrossRef]
  28. Park, S.H.; Jang, J.H.; Wistara, N.J.; Febrianto, F.; Lee, M. Fuel properties of Indonesian bamboo carbonized at different temperatures. BioResources 2019, 14, 4224–4235. [Google Scholar] [CrossRef]
  29. Hu, W.; Feng, Z.; Yang, J.; Gao, Q.; Ni, L.; Hou, Y.; He, Y.; Liu, Z. Combustion behaviors of molded bamboo charcoal: Influence of pyrolysis temperatures. Energy 2021, 226, 120253. [Google Scholar] [CrossRef]
  30. Fromm, O.; Heckmann, A.; Rodehorst, U.C.; Frerichs, J.; Becker, D.; Winter, M.; Placke, T. Carbons from biomass precursors as anode materials for lithium ion batteries: New insights into carbonization and graphitization behavior and into their correlation to electrochemical performance. Carbon 2018, 128, 147–163. [Google Scholar] [CrossRef]
  31. Su, R.; Dong, X. Preparation and electrochemical properties of bamboo-based carbon for lithium-ion-battery anode material. Int. J. Electrochem. Sci. 2019, 14, 2452–2461. [Google Scholar] [CrossRef]
  32. Hata, T.; Yamane, K.; Kobayashi, E.; Imamura, Y.; Ishihara, S. Microstructural investigation of wood charcoal made by spark plasma sintering. J. Wood Sci. 1998, 44, 332–334. [Google Scholar] [CrossRef]
  33. Yamane, T.; Ishihara, S.; Hata, T. Effects of sintering temperature on structural changes of wood charcoal. Tanso 1999, 1999, 2–6. [Google Scholar] [CrossRef]
  34. Kawamura, K.; Amari, M.; Aruga, A.; Ozawa, S. Changes of Bending Strength and Microstructure of Charcoals with High Temperature Treatment. Tanso 2000, 2000, 32–36. [Google Scholar] [CrossRef]
  35. Hata, T.; Vystavel, T.; Bronsveld, P.; DeHosson, J.; Kikuchi, H.; Nishimiya, K.; Imamura, Y. Catalytic carbonization of wood charcoal: Graphite or diamond? Carbon 2004, 42, 961–964. [Google Scholar] [CrossRef]
  36. Fogg, J.L.; Putman, K.J.; Zhang, T.; Lei, Y.; Terrones, M.; Harris, P.J.; Harris, P.J.F.; Marks, N.A.; Suarez-Martinez, I. Catalysis-free transformation of non-graphitising carbons into highly crystalline graphite. Commun. Mater. 2020, 1, 47. [Google Scholar] [CrossRef]
  37. Inagaki, M.; Naka, S. Crystallite orientation in polycrystalline graphites made from glass-like carbons under high pressure. J. Mater. Sci. 1975, 10, 814–818. [Google Scholar] [CrossRef]
  38. Nishimiya, K.; Hata, T.; Kikuchi, H.; Imamura, Y. Effect of aluminum compound addition on graphitization of wood charcoal by direct electric pulse heating method. J. Wood Sci. 2004, 50, 177–181. [Google Scholar] [CrossRef]
  39. Knight, D.S.; White, W.B. Characterization of diamond films by Raman spectroscopy. J. Mater. Res. 1989, 4, 385–393. [Google Scholar] [CrossRef]
  40. Ramirez-Rico, J.; Gutierrez-Pardo, A.; Martinez-Fernandez, J.; Popov, V.V.; Orlova, T.S. Thermal conductivity of Fe graphitized wood derived carbon. Mater. Des. 2016, 99, 528–534. [Google Scholar] [CrossRef]
  41. Yoshida, A.; Kaburagi, Y.; Hishiyama, Y. Full width at half maximum intensity of G band in first order Raman spectrum of carbon material as a parameter for graphitization-a study with pyrolytic carbons. Tanso 2006, 2006, 2–7. [Google Scholar] [CrossRef]
  42. Yu, M.; Saunders, T.; Su, T.; Gucci, F.; Reece, M.J. Effect of heat treatment on the properties of wood-derived biocarbon structures. Materials 2018, 11, 1588. [Google Scholar] [CrossRef] [PubMed]
  43. Togonon, J.J.H.; Chiang, P.-C.; Lin, H.-J.; Tsai, W.-C.; Yen, H.-J. Pure carbon-based electrodes for metal-ion batteries. CarbonTrends 2021, 3, 100035. [Google Scholar] [CrossRef]
  44. Vook, T.; Dey, S.C.; Yang, J.; Nimlos, M.; Park, S.; Han, S.D.; Sagues, W.J. Sustainable Li-ion anode material from Fe-catalyzed graphitization of paper waste. J. Energy Storage 2023, 73, 109242. [Google Scholar] [CrossRef]
Crystals 14 00914 g001
Figure 1. Schematic diagram of heat treatment process.
Figure 1. Schematic diagram of heat treatment process.
Crystals 14 00914 g001
Crystals 14 00914 g002
Figure 2. Thermogravimetric analysis of oak-based white charcoal in N2.
Figure 2. Thermogravimetric analysis of oak-based white charcoal in N2.
Crystals 14 00914 g002
Crystals 14 00914 g003
Figure 3. Changes in carbon content according to elemental analysis.
Figure 3. Changes in carbon content according to elemental analysis.
Crystals 14 00914 g003
Crystals 14 00914 g004
Figure 4. SEM observations of wood-based heat-treated white charcoals: (A) oak, 1800 °C, 60 min., (B) oak, 2400 °C, 10 min., (C) bamboo, 1800 °C, 60 min., (D) bamboo, 2400 °C, 10 min., in Ar.
Figure 4. SEM observations of wood-based heat-treated white charcoals: (A) oak, 1800 °C, 60 min., (B) oak, 2400 °C, 10 min., (C) bamboo, 1800 °C, 60 min., (D) bamboo, 2400 °C, 10 min., in Ar.
Crystals 14 00914 g004
Crystals 14 00914 g005
Figure 5. TEM observations of wood-based heat-treated white charcoals: (A) oak, 1800 °C, 60 min., (B) bamboo, 1800 °C, 60 min., (C) oak, 2000 °C, 30 min., (D) bamboo, 2000 °C, 30 min., (E) oak, 2400 °C, 10 min., (F) bamboo, 2400 °C, 10 min., (G) oak, 2400 °C, 10 min., d002, (H) bamboo, 2400 °C, 10 min., d002 in Ar.
Figure 5. TEM observations of wood-based heat-treated white charcoals: (A) oak, 1800 °C, 60 min., (B) bamboo, 1800 °C, 60 min., (C) oak, 2000 °C, 30 min., (D) bamboo, 2000 °C, 30 min., (E) oak, 2400 °C, 10 min., (F) bamboo, 2400 °C, 10 min., (G) oak, 2400 °C, 10 min., d002, (H) bamboo, 2400 °C, 10 min., d002 in Ar.
Crystals 14 00914 g005
Crystals 14 00914 g006
Figure 6. XRD spectra comparison of oak [21] and bamboo-based white charcoal after heat treatment at 2400 °C.
Figure 6. XRD spectra comparison of oak [21] and bamboo-based white charcoal after heat treatment at 2400 °C.
Crystals 14 00914 g006
Crystals 14 00914 g007
Figure 7. Raman spectra of oak-based white charcoal [21] and bamboo-based white charcoal after heat treatment at 2400 °C.
Figure 7. Raman spectra of oak-based white charcoal [21] and bamboo-based white charcoal after heat treatment at 2400 °C.
Crystals 14 00914 g007
Crystals 14 00914 g008
Figure 8. (A) Rate capability at various current densities, (B) charge-discharge graph of hard carbon made from bamboo at 2000 °C, (C) charge-discharge graph of soft carbon made from bamboo at 1800 °C.
Figure 8. (A) Rate capability at various current densities, (B) charge-discharge graph of hard carbon made from bamboo at 2000 °C, (C) charge-discharge graph of soft carbon made from bamboo at 1800 °C.
Crystals 14 00914 g008
Table 1. Specific surface area (ABET), total volume (Vt), the ratio of the micropore volume (Vmi), and the average pore diameter (Dm) of white charcoals powdered, MWCNT, and graphene.
Table 1. Specific surface area (ABET), total volume (Vt), the ratio of the micropore volume (Vmi), and the average pore diameter (Dm) of white charcoals powdered, MWCNT, and graphene.
No.Charcoal Size (mm)ABET (m2/g)Vt (cm3/g)Vmi (cm3/g)
(Vmi/Vt)%		Dm (nm)
1>4.7513.80.010.0071 (71.00)2.89
24.75–3.35 (4.05)152.560.0990.0824 (83.23)2.8
33.35–2.36 (2.85)220.670.13530.1080 (79.82)2.45
42.36–2.00 (2.18)206.790.1180.0882 (74.75)2.28
52.00–1.70 (1.85)319.450.15470.1304 (84.29)1.94
6<1.70352.010.14530.1381 (95.04)1.65
7Powder A (10 μm)816.20.32870.3134 (95.35)1.61
8Powder B (4 μm)412.490.21240.1676 (78.91)2.06
Table 2. Elemental analysis of high-temperature heat-treated bamboo-based white charcoals and oak-based white charcoals (%). Hydrogen (H, %) = 100% − C(%) − N(%) − O(%).
Table 2. Elemental analysis of high-temperature heat-treated bamboo-based white charcoals and oak-based white charcoals (%). Hydrogen (H, %) = 100% − C(%) − N(%) − O(%).
Charcoal
(°C/min.)		Carbon (C, %)Nitrogen (N, %)Oxygen (O, %)
BambooOakBambooOakBambooOak
1000 °C, 60 min.92.1279.360.710.887.1719.36
1100 °C, 60 min.93.3491.880.240.786.427.01
1300 °C, 60 min.93.6492.350.160.656.206.84
1500 °C, 60 min.96.5097.250.070.473.432.28
1800 °C, 60 min.98.4899.880.000.001.520.04
2000 °C, 30 min.100.00100.000.000.000.000.00
2400 °C, 10 min.100.00100.000.000.000.000.00
Table 3. Intensity (G/(G + D)) of heat-treated bamboo-based white charcoals and oak-based white charcoals.
Table 3. Intensity (G/(G + D)) of heat-treated bamboo-based white charcoals and oak-based white charcoals.
Samples1500 °C1800 °C2400 °C
OakBambooOakBambooOakBamboo
Intensity
(G/(G + D))		0.3511450.45652170.4955490.46803650.55172410.9175258
Raman Shift (D)134913531347135413441344
Intensity (D)17075170233658
Raman Shift (G)159215991583158315751580
Intensity (G)92631672058089
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Lee, K.; Ryu, S.-K.; Kim, H.-G.; Kwac, L.-K.; Kim, Y.-S. Comparative Analysis of Graphitization Characteristics in Bamboo and Oak Charcoals for Secondary Battery Anodes. Crystals 2024, 14, 914. https://doi.org/10.3390/cryst14110914

AMA Style

Lee K, Ryu S-K, Kim H-G, Kwac L-K, Kim Y-S. Comparative Analysis of Graphitization Characteristics in Bamboo and Oak Charcoals for Secondary Battery Anodes. Crystals. 2024; 14(11):914. https://doi.org/10.3390/cryst14110914

Chicago/Turabian Style

Lee, Kiseon, Seung-Kon Ryu, Hong-Gun Kim, Lee-Ku Kwac, and Young-Soon Kim. 2024. "Comparative Analysis of Graphitization Characteristics in Bamboo and Oak Charcoals for Secondary Battery Anodes" Crystals 14, no. 11: 914. https://doi.org/10.3390/cryst14110914

APA Style

Lee, K., Ryu, S.-K., Kim, H.-G., Kwac, L.-K., & Kim, Y.-S. (2024). Comparative Analysis of Graphitization Characteristics in Bamboo and Oak Charcoals for Secondary Battery Anodes. Crystals, 14(11), 914. https://doi.org/10.3390/cryst14110914

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop