High-temperature Carbonization Research Articles

Ultrafine Fe-Mn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofiber electro-Fenton membrane with strong metal-support interactions for sustainable water decontamination in wide pH ranges

Designing a membrane electrode with high activity and anti-scaling ability in a wide pH range is crucial to the development of flow-through electro-Fenton system. Herein, we reported a novel porous membrane composed of ultrafine FeMn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofibers (FeMn/N-CNF) obtained through a facile electrospinning-carbonization process. The strong metal-support interaction (SMSI) phenomena including carbon encapsulation structure and electron transfer from metal to N-CNF, beneficial to the intrinsic activities, were successfully induced by the enhanced interfacial metal-nitrogen bonding in FeMn/N-CNF. Microstructural characterizations and leaching test revealed that the SMSI encapsulation structure could promote the formation of ultrafine FeMn nanoparticles in N-CNF during the high-temperature carbonization process and prevent leaching of active Fe/Mn metals into solution across a wide pH range. The constructed gravity-driven flow-through electro-Fenton system based on a FeMn/N-CNF cathode membrane exhibited superior performance to generate H2O2 (36.23 mmol L−1 h−1) and subsequent activate H2O2 decomposition to hydroxyl radicals (0.1024 min−1), achieving remarkable degradation efficiencies of 96.8%, 92.3%, and 90.3% within 60 min for Rhodamine B, Tetracycline, and Methyl Orange, respectively. Furthermore, the FeMn/N-CNF membrane filter demonstrated good pH adaptability, excellent cycle stability and anti-scaling ability during the degradation process. This work offers a viable avenue to enhance degradation performance and environmental robustness for practical water decontamination via achieving SMSI effect in carbon-supported electro-Fenton membranes.

Constructed Ru@Cr3N0.4C1.6 heterostructure on carbon nanofibers for efficient hydrogen evolution reaction in alkaline media

The development of an efficient and low-cost electrocatalyst is critical to the hydrogen evolution reaction (HER). Herein, we reported a Ru@Cr3N0.4C1.6 nanoparticles grown on carbon nanofibers, which was prepared by electrospinning and high temperature carbonization strategies. The introduction of Ru metal helps Cr3N0.4C1.6 nanoparticles expose active sites on the surface of CNF to improve the catalytic performance, while the introduction of Cr optimizes the binding energy of Ru-H to achieves higher catalytic activity. Moreover, the heterogeneous structure formed by Ru metal and Cr3N0.4C1.6 nanoparticles also contributed to the catalytic performance. Therefore, the Ru@Cr3N0.4C1.6/CNF exhibited excellent catalytic activity with a low overpotential of 35 mV to obtain current density of 10 mA cm−2 in 1 M KOH. And it also showed outstanding long-term stability after continuously working for 200 h. This work provides a new method to prepare catalysts efficiently and cheaply.

Multi-Parameter Experimental Investigation on the Characteristics of Acidizing Effectiveness in High-Temperature Carbonate Formation

Carbonate formation is the key reservoir in Sichuan Basin for natural gas development. Compared with the early stage of development, the burial depth of targeted formation becomes deeper, and the formation temperature gets higher. So, the characteristics of acidizing effectiveness in high-temperature carbonate formations make this evaluation slightly difficult. Currently, it is common that a single parameter is considered to study acidizing effectiveness by simulation and experiment methods. In this paper, for a more accurate investigation of acidizing effectiveness, multiple parameters, including permeability change rate, fracture conductivity, and surface roughness, were introduced by a series of experiments. It is revealed that the permeability change rate is more than 57% when using gelled acid. As the amount of diverting agent increases in diverting acid, the viscosity of the acid grows to its peak with the reaction, making it easier to block the high permeability core temporarily and divert to acidify the low permeability core, where the permeability change rate of the low permeability core goes from 51.6% to 64.2%, which shows well acidizing effectiveness. In addition, the short-term and long-term conductivity of the samples from the three different formations are more than 200 mD∙m under high closure stress. The conductivity of Maokou Formation is the largest due to its high content of carbonate minerals and high dissolution rate. And the results of long-term conductivity are consistent with those of surface roughness, making the evaluation results more reliable for acidizing effectiveness. It is worth noting that temperature is a factor that cannot be ignored in the evaluation of acidizing effectiveness because it has a great influence on the performance of the acid system, such as viscosity and the reaction-reduced rate, leading to an acidizing effectiveness affect. So, the temperature resistance of an acid system is important as well.

Synthesis of C@Si composite materials for lithium battery anode using Chinese rose as carbon source

As a promising anode for lithium-ion batteries (LIBs), silicon (Si) has been studied due to its high specific capacity. However, significant volume change during charge-discharge process has seriously impeded its practical application. Compounding with carbon is one of the methods to solve this problem. In this paper, biomass carbon is prepared by high temperature carbonization of Chinese rose petals. Different mass ratios of Si nanoparticles are embedded in the biomass carbon to produce C@Si composites. The as-prepared C@Si composites are assembled into LIBs to investigate their electrochemical performance. As an anode material for LIBs, the manufactured C@Si composite material (Si-25 wt%) manifests a stable cycling performance (524 mAh•g−1 at 0.1 A•g−1 after 100 cycles), a long cycle life (581 mAh•g−1 at 1 A•g−1 after 400 cycles) and excellent rate capability. And its initial coulombic efficiency at the current density of 1 A•g−1 (99.62 %) is much larger than that of pure nano-Si (29.45 %). The electrochemical impedance spectroscopy (EIS) results indicate that the C@Si composite materials can behave as an ideal capacitor. This study reveals the possibility of changing flower petals to carbon material and the potential applications in the field of LIBs.

Surface charge alteration of charcoal derived from bamboo leaves and understanding the interaction with anionic and cationic dye

Cost-effective adsorbents derived from regenerative sources provide a sustainable solution to the pressing environmental pollution challenges. Conventional studies often rely on biochar-based adsorbents obtained at high carbonization temperatures in an induced environment. The present study explored the efficacy of carbon derived from the stems (CBS) and leaves (CBL) of bamboo plants as efficient dye adsorbents at low carbonization temperatures. CBL carbonized at 350 °C exhibited a remarkable dye adsorption efficiency of 90%, significantly outperforming CBS, which achieved only 39% efficiency. To enable the adsorption of both dyes, heterophase metal oxides, specifically Fe-doped ZnO and ZnFe2O4 were incorporated. Zeta potential measurements revealed a transition from negative to positive values with metal oxide incorporation, suggesting alterations in the surface acidity and functional group composition. The adsorption performance of the composite (WC20) sample was evaluated using Congo Red (CR) and Crystal Violet (CV) dyes. Comprehensive studies on the adsorption kinetics, isotherm modeling, and thermodynamics have been conducted to identify WC20 as the most effective composite. The equilibrium adsorption data aligned well with the Langmuir isotherm model, demonstrating maximum adsorption capacities of 65.31 mg g−1 for CR and 38.05 mg g−1 for CV at room temperature of 298 K with constant pH. Thermodynamic analysis indicated a hybrid adsorption mechanism, wherein CR adsorption was predominantly driven by chemisorption, whereas CV adsorption was governed by physisorption. Mechanistic insights have revealed that electrostatic interactions and π–π stacking play crucial roles in dye removal. These findings underscore the potential applicability of WC20 as a cost-effective and efficient adsorbent for the remediation of both cationic (CV) and anionic (CR) dyes in wastewater, highlighting its viability for future environmental management and pollution mitigation strategies.

The induced formation and regulation of closed-pore structure for biomass hard carbon as anode in sodium-ion batteries

Biomass hard carbon is regarded as an advanced anode materials for sodium ion batteries (SIBs) since it possesses balanced performance including satisfactory specific capacity, suitable operating voltage window and low cost. Although numerous instances of utilizing biomass-derived hard carbon in SIBs have been observed, the unregulated pore structure of these hard carbon materials significantly constrains the electrochemical performance of SIBs, leading to diminished initial Columbic efficiency (ICE) and plateau capacity. Herein, taking a biomass hard carbon derived from waste camellia seed shells (CSSHCs) as a template, we display a correlation between synthesis conditions and pore structure of CSSHCs. CSSHCs are synthesized via a facile route including pre‑carbonization, purifying, mechanical ball-milling and high-temperature carbonization, and it is found that adjusting the secondary calcination temperature can induce the formation of closed pore structure, which is of great benefit to increase the ICE and the plateau-capacity. Besides, it is also proved that the obtained CSSHCs anodes obey a sodium storage mechanism that can be classified as “adsorption-intercalation-pore filling”, which endows SIBs with a competitive electrochemical performance. Specifically, the obtained biomass hard carbons at 1300 °C exhibits the best electrochemical performance among these anodes with the reversible capacity of as high as 270.0 mAh g−1 and a high ICE of 80.1 %, together with an excellent cycle stability (91.0 % capacity retention after 200 cycles at 0.1C, 1C = 300 mA g−1). Therefore, this study provides a significant exploration and raw material support for the further utilization of the waste biomass and sustainable development of the anode materials for the large-scale application of SIBs.

Lithium-Containing Sorbents Based on Rice Waste for High-Temperature Carbon Dioxide Capture

This article studies the influence of the nature of the carrier from rice wastes on the sorption properties of lithium-containing sorbents, and also considers the impact of the modifying additive (K2CO3) and adsorption temperature on their characteristics. It has been shown that the sorption capacity of 11LiK/SiO2 at 500 °C reached 36%, which is associated with the formation of lithium orthosilicate in the sorbent composition, as well as with an increase in the specific surface area of the sorbent. After 12 cycles of sorption–desorption, it was found that the sorption capacity of 11LiK/SiO2 for CO2 decreased by only 8%. Rice waste-based sorbents have a high sorption capacity for CO2 at high temperatures, which allows them to be used for carbon dioxide capture. The results of this study indicate the prospects of using agricultural residues to create effective adsorbents that contribute to reducing environmental pollution and combating global warming.

Research on the Performance of New Microbial Fuel Cell Anodes

In recent years, with the vigorous development of the maritime transportation industry, the resulting problem of ship oil pollution has become increasingly prominent. Efficient and thorough treatment of oily wastewater is the key to solving such problems. Microbial fuel cell (MFC) technology is a promising biological treatment method due to its good degradation effect, no secondary pollution, and energy recovery. In this paper, the discarded corn cob materials in nature were selected for high-temperature carbonization at 350°C, and NaOH was used to modify the modified biochar. Then, the coating technology of Ti3C2 MXene, NbC, WC, TaC and other materials was used to modify the surface of biochar, and the biochar anode material was obtained to construct a double-chamber microbial fuel cell device. The properties of the modified anode biochar materials were studied.

Regulation of surface oxygen functional groups in starch-derived hard carbon via pre-oxidation: A strategy for enhanced sodium storage performance

During the process of sodium storage in hard carbon anodes, the significance of surface oxygen functional groups cannot be overlooked. In this work, we utilize starch as raw material to synthesize hard carbon by the process of pre-oxidation and two-step carbonization. XPS analysis reveals that pre-oxidation bolsters the presence of CO bonds, thereby providing more active sites. TEM analysis reveals that hard carbon with pseudo-graphite and graphite-like structure is obtained at relatively high carbonization temperature (1400 °C), and the formation of closed pores results in lower specific surface area. The introduction of appropriate oxygen-containing groups in pre-oxidation process can facilitate the cross-linking of starch chains, promoting the increase of defect sites and the sodium storage performance of hard carbon. A series of samples are prepared at various pre-oxidation temperature. Among them, P200-HC obtained after pre-oxidation at 200 °C and carbonization at 1400 °C exhibits the highest reversible specific capacity of 342.7 mAh g−1 at current density of 0.1 C with an initial Coulombic efficiency of 71.1 %, and capacity retention of 87.3 % at current density of 1 C. The work presents a viable approach for the synthesis of hard carbon derived from starch, thereby expanding the design tactic of sodium-ion batteries with improved performance.

Significant performance enhancement of Zn-ion hybrid supercapacitors based on microwave-assisted pyrolyzed active carbon via synergistic effect of NaHCO3 activation and CNT networks

Zinc-ion hybrid supercapacitors (ZIHSCs) represents a promising technological approach for large-scale energy storage with the combined advantages of supercapacitors and zinc-ion batteries. Unfortunately, it is still challengeable to quickly fabricate low-cost, high-performance carbonaceous cathode materials at relatively low temperature. To address such issues, herein, taking waste Eucommia ulmoides Oliver (EUO) wood as an example, we present a novel microwave-assisted carbonization (MWC) approach at relatively low temperature to quickly prepare active carbon, and we present a synergistic strategy to significantly enhance the electrochemical performance by introducing sodium bicarbonate activation (SA) and constructing conductive carbon nanotubes (CNT) networks. The MWC-SA@CNT hybrid exhibits outstanding specific capacitance of 344.2 F/g at 0.2 A/g within three-electrode system, much better than conventional high-temperature pyrolyzed AC, MWC carbon, and MWC-SA carbon. The superior performance of MWC-SA@CNT can be attributed to the synergistic effect of its large specific surface area of 1102.7 m2/g, high mesoporous percentage of 53.5%, and rich –OH and CO groups due to microwave-assisted carbonization and sodium bicarbonate activation, and rich electron transport paths due to the presence of CNT networks. Furthermore, ZIHSCs assembled by MWC-SA@CNT cathode could delivers impressive performance with excellent capacity (194.37 mA h/g at current density of 1 A/g), energy density (142.30 Wh/kg), and durability (capacitance retention rate of 97.65% after 5000 cycles). This work offers a rapid and low-temperature method for preparing wood-based active carbon with rich nanopores and strong conductivity to improve performance of Zinc ion storage.

Experimental study on mechanical properties and breakage of high temperature carbon fiber-bar reinforced concrete under impact load

To investigate the effects of high temperature and carbon fiber-bar reinforcement on the dynamic mechanical properties of concrete materials, a muffle furnace was used to treat two kinds of specimens, plain and carbon fiber-bar reinforced concrete, at high temperatures of 25, 200, 400 and 600 °C. Impact compression tests were carried out on two specimens after high-temperature exposure using a Hopkinson pressure bar (SHPB) test setup combined with a high-speed camera device to observe the crack extension process of the specimens. The effects of high temperature and carbon fiber-bar reinforcement on the peak stress, energy dissipation density, crack propagation and fractal dimension of the concrete were analyzed. The results showed that the corresponding peak strengths of the plain concrete specimens at 25, 200, 400, and 600 °C were 88.37, 93.21, 68.85, and 54.90 MPa, respectively, and the peak strengths after the high-temperature exposure first increased slightly and then decreased rapidly. The mean peak strengths corresponding to the carbon fiber-bar reinforced concrete specimens after high-temperature action at 25, 200, 400, and 600 °C are 1.13, 1.13, 1.21, and 1.19 times that of plain concrete, respectively, and the mean crushing energy consumption densities are 1.27, 1.31, 1.73, and 1.59 times that of plain concrete, respectively. The addition of carbon fiber-bar reinforcement significantly enhanced the impact resistance and energy dissipation of the concrete structure, and the higher the temperature was, the more significant the increase. An increase in temperature increases the number of crack extensions and width, and the high tensile strength of the carbon fiber-bar reinforcement and the synergistic effect with the concrete material reduce the degree of crack extension in the specimen. The fractal dimension of the concrete ranged from 1.92 to 2.68, that of the carbon fiber-bar reinforced concrete specimens ranged from 1.61 to 2.42, and the mean values of the corresponding fractal dimensions of the plain concrete specimens after high-temperature effects at 25, 200, 400, and 600 °C were 1.19, 1.21, 1.10, and 1.11 times those of the fiber-reinforced concrete specimens, respectively. The incorporation of carbon fiber-bar reinforcement reduces the degree of rupture and fragmentation of concrete under impact loading and improves the safety and stability of concrete structures.

A novel synthesis of porous Ba2Co2Mn1.2Fe10.8O22/carbon composites for high efficiency electromagnetic wave absorption

Designing an electromagnetic wave (EMW) absorbing material with ultra-wide effective absorption bandwidth (EAB) and low filling ratio is the key to solving the problem of electromagnetic pollution. In this study, the porous Ba2Co2Mn1.2Fe10.8O22/C (Mn-Co2Y/C) composites were prepared by radial freeze-drying method as well as high temperature carbonization process (400 °C, 500 °C, 600 °C, and 700 °C). The research results indicate that the sample annealed at 600 °C exhibits superior EMW absorption properties, achieving the widest EAB of 5.77 GHz at a thickness of 1.7 mm, which is attributed to the synergistic effect of multiple reflections of EMWs within microchannels of the samples and the interfacial polarization between Mn-Co2Y ferrite and C material. Samples prepared at 600 °C have the best impedance matching, which makes it easier for EMWs to enter the material, thus exhibiting better EMW absorption performance. The magnetic loss mainly originates from natural resonance at low frequencies and eddy current loss at high frequencies, and the dielectric loss stems from relaxation loss and conductivity loss.

Study on the absorbing properties and regulatory mechanism of NiCo/C materials prepared by MOFs derivative method

In order to solve the electromagnetic pollution problem, NiCo-MOFs-74 material was used as the parent material, and the new NiCo/C composite was prepared by high temperature carbonization method. The results show that the wave absorbing properties of NiCo/C composites change significantly with the change of the molar ratio of Ni/Co. When the molar ratio of Ni/Co is 1:1, the absorption performance of Ni1Co1/C composite is the best at the frequency of 16.75 GHz, the best reflection loss at 2.5 mm thickness is −51.5 dB, and the effective absorption bandwidth is 3.39 GHz.

Effect of Mg modification on the catalytic performance of zinc malachite for methanol synthesis

The complex conditions of methanol production from coke-oven gas have brought challenges to the copper-based methanol synthesis catalyst. In this work, a series of zinc-malachite samples with different Mg contents were prepared. The zinc-malachite and calcined samples were characterized by in-situ X-ray diffraction (XRD), thermogravimetry-mass spectrometry (TG-MS), N2 physical adsorption, H2 programmed temperature reduction (H2-TPR), CO2 programmed temperature desorption (CO2-TPD) and other methods. The effects of Mg addition on the structure of zinc-malachite and its catalytic performance of methanol synthesis were investigated. The results showed that the addition of Mg increased the degree of Cu substitution inside the zinc-malachite structure and promoted the formation of high temperature carbonates in the catalyst after roasting. With the increase of Mg content, the specific surface area of the calcined catalyst increased gradually, and the Cu grain size decreased simultaneously. In-situ XRD results showed that a small amount of Mg could effectively inhibit the growth of copper grain size during the heat treatment. The evaluation showed that the initial activity of the catalyst increased first and then decreased with Mg addition, and the activity of the Mg-doped catalyst remained at a relatively high level after heat treatment. The appropriate Mg addition is beneficial to the initial activity and thermal stability of Cu-based methanol synthesis catalyst.

Geochemical constraints on depositional environment of metacarbonate rocks from the Neoproterozoic Cauvery Suture Zone, Southern Granulite Terrane, India

ABSTRACT Metacarbonates serve as proxies for understanding the chemical oceanography of the present, as well as the past-day ocean’s evolution history and these are extensively described in the Neoproterozoic-Cambrian collisional belts of East Gondwana. The Cauvery Suture Zone (CSZ), Southern Granulite Terrane (SGT), India, is one such prominent example of their occurrence, along with several Precambrian dismembered ophiolites, arc-related intrusions and other metamorphic rocks. These are dominantly exposed in the western, southern and south-central parts of the suture, around the Neoproterozoic Kadavur Gabbro-Anorthosite and Manamedu Ophiolite Complexes. Their whole-rock geochemistry reveals the protoliths of metacarbonates have been derived from different sources of continental inputs and deposited under open to passive margin settings. The δ13C(V-PDB)) - δ18O(V-SMOW) data (−0.01 to + 3.03‰; +15.81 to + 24.84‰) reveal as high-temperature carbonates of typical limestone variety, deposited under warmer palaeoclimatic conditions of the marine environment and later subjected to metamorphism. The presence of higher 87Sr/86Sr ratios (0.707514 to 0.71511) and negative εNd values (−17.3 to −10) suggests that they originated from large crustal inputs with more interactions of seawater with the sediments, evolved during Ediacaran to early Cambrian periods. The above results reveal that these are possible remnants of the Neoproterozoic Mozambique Ocean and coeval with the metacarbonates of Sør Rondane Mountains-East Antarctica, Highland Complex-Sri Lanka, Madagascar and Mozambique Belts of Neoproterozoic Gondwana.

Mercerization-enhanced cellulose-II cotton fiber-based low-temperature hard carbon for sodium-ion batteries

Hard carbons from cellulose are highly regarded as promising anode options for sodium-ion batteries (SIBs). However, a high carbonization temperature (>1300 °C) is usually required to obtain high-performance hard carbons, which leads to high-energy consumption and high cost. Moreover, hard carbons generally have poor rate capability and unsatisfactory cyclability which restrict their commercial applications. Herein, a low-temperature (900 °C) approach for the preparation of high-quality hard carbons for SIBs from waste cotton fibers is reported. It involves a mercerization pretreatment to convert cellulose-I cotton fibers into cellulose-II structure and dissolve the amorphous cellulose to form highly crystalline cellulose. This pretreatment process benefits forming abundant pseudo-graphitic structures at a low carbonization temperature of 900 °C. Consequently, the mercerized cotton fibers-based carbons (MCFC) exhibit excellent sodium storage properties, possessing a high capacity (316 mAh g−1 at 0.1 A g−1), high-rate capability (210 mAh g−1 at 10 A g−1), and long-term cyclability (83.2 % retention after 3000 cycles). This mercerization approach coupled with waste cotton fibers provides a sustainable pathway for the preparation of high-quality hard carbons for SIBs.

Luffa vines-derived N, O doped porous carbon with high surface area for supercapacitors

Considerable attention has been devoted to creating porous carbons with exceptional surface area and porosity from biomass waste for energy storage devices. Herein, we employed a straightforward high-temperature carbonization and KOH activation method to synthesize nitrogen (N) and oxygen (O) co-doped porous activated carbons derived from luffa vines (LVACs). The impact of varying KOH concentrations on the morphology, structure, and electrochemical properties of LVACs was thoroughly investigated. The optimal mass ratio of KOH to LVACs at 1:6 achieved the maximum specific surface area of 3369 m2 g−1. At a current density of 1 A g−1, the LASC-6 electrode exhibits an impressive specific capacitance of 348.5 F g−1. It also demonstrates exceptional rate performance, retaining 70.6 % of its capacitance at a current density of 20 A g−1. The electrode possesses robust cycling stability, retaining 90 % of the initial capacitance after 5000 cycles. We assessed the practicality of LVAC-6 by constructing symmetric supercapacitors (SSCs) using KOH and [BMIM]BF4 electrolytes. The KOH and [BMIM]BF4 SSCs achieved specific capacitances of 86.75 and 50.31 F g−1, respectively, at a current density of 0.25 A g−1. Moreover, the [BMIM]BF4 SSC exhibited an impressive energy density of 51.05 Wh kg−1 at a power density of 346.15 W kg−1. Therefore, we propose a simple and cost-effective strategy to produce porous carbon materials with excellent electrochemical performance from discarded biomass waste, facilitating the preparation of environmentally friendly electrode materials for high-performance supercapacitors.

MOF-derived molybdenum carbide-copper as an electrocatalyst for the hydrogen evolution reaction

We have used molybdenum-copper metal-organic framework (Mo-Cu MOF) as a precursor, and its porous structure as a spatially confined environment to suppress the overgrowth and aggregation of nanoparticles during high-temperature carbonization for synthesis of MOF-derived molybdenum carbide-copper. The Mo-Cu-MOF precursor was carbonized at high temperature under a predefined gas flow condition (nitrogen → 20 % methane/hydrogen mixed gas) and the product was transformed from MoO2-Cu to ŋ-MoC-Cu. Then, by changing the process temperature (800°C → 1000°C), ŋ-MoC-Cu was transformed into β-Mo2C-Cu. The microstructure analysis by transmission electron microscopy (TEM) revealed a gradual change of octahedral structure of MoxC-Cu with the increase of temperature. X-ray diffraction (XRD) analysis identify the phase composition and the grain size of carbide molybdenum inside the MoxC-Cu structure. The carbide molybdenum grain size increased and transformed from ŋ-MoC to β-Mo2C with the increase of the carbonization temperature from 800 °C to 1000 °C. ŋ-MoC-Cu obtained at a carbonization temperature of 800°C showed the best electrochemical performance, with η10 mA = −233 mV and Tafel slope = 73 mV/dec.

Fast-Hardening Production of High-Strength BOFS Aggregates by High-Temperature Carbonation Curing

Fast-Hardening Production of High-Strength BOFS Aggregates by High-Temperature Carbonation Curing

Regulating the Pore Structure of Biomass-Derived Hard Carbon for an Advanced Sodium-Ion Battery.

Biomass-derived hard carbon materials are attractive for sodium-ion batteries due to their abundance, sustainability, and cost-effectiveness. However, their widespread use is hindered by their limited specific capacity. Herein, a type of bamboo-derived hard carbon with adjustable pore structures is developed by employing a ball milling technique to modify the carbon chain length in the precursor. It is observed that the length of the carbon chain in the precursor can effectively control the rearrangement behavior of the carbon layers during the high-temperature carbonization process, resulting in diverse pore structures ranging from closed pores to open pores, which significantly impact the electrochemical properties. The optimized hard carbon with abundant closed pores exhibits a high specific capacity of 356 mAh g-1 at 20 mA g-1, surpassing that of bare hard carbon (243 mAh g-1) and hard carbon with abundant open pores (129 mAh g-1 at 20 mA g-1). However, the kinetic analysis reveals that hard carbon with open pores shows better sodium-ion diffusion kinetics, indicating that a balance between the closed and open pores should be considered. This research offers valuable insights into pore design and presents a promising approach for enhancing the performance of hard carbon anode materials derived from biomass precursors.