Biomass-derived Carbon Materials Research Articles

Biomass-Derived Carbon Materials for Advanced Metal-Ion Hybrid Supercapacitors: A Step Towards More Sustainable Energy

Modern research has made the search for high-performance, sustainable, and efficient energy storage technologies a main focus, especially in light of the growing environmental and energy-demanding issues. This review paper focuses on the pivotal role of biomass-derived carbon (BDC) materials in the development of high-performance metal-ion hybrid supercapacitors (MIHSCs), specifically targeting sodium (Na)-, potassium (K)-, aluminium (Al)-, and zinc (Zn)-ion-based systems. Due to their widespread availability, renewable nature, and exceptional physicochemical properties, BDC materials are ideal for supercapacitor electrodes, which perfectly balance environmental sustainability and technological advancement. This paper delves into the synthesis, functionalization, and structural engineering of advanced biomass-based carbon materials, highlighting the strategies to enhance their electrochemical performance. It elaborates on the unique characteristics of these carbons, such as high specific surface area, tuneable porosity, and heteroatom doping, which are pivotal in achieving superior capacitance, energy density, and cycling stability in Na-, K-, Al-, and Zn-ion hybrid supercapacitors. Furthermore, the compatibility of BDCs with metal-ion electrolytes and their role in facilitating ion transport and charge storage mechanisms are critically analysed. Novelty arises from a comprehensive comparison of these carbon materials across metal-ion systems, unveiling the synergistic effects of BDCs’ structural attributes on the performance of each supercapacitor type. This review also casts light on the current challenges, such as scalability, cost-effectiveness, and performance consistency, offering insightful perspectives for future research. This review underscores the transformative potential of BDC materials in MIHSCs and paves the way for next-generation energy storage technologies that are both high-performing and ecologically friendly. It calls for continued innovation and interdisciplinary collaboration to explore these sustainable materials, thereby contributing to advancing green energy technologies.

Biomass Waste Utilization as Nanocomposite Anodes through Conductive Polymers Strengthened SiO2/C from Streblus asper Leaves for Sustainable Energy Storages.

Sustainable anode materials, including natural silica and biomass-derived carbon materials, are gaining increasing attention in emerging energy storage applications. In this research, we highlighted a silica/carbon (SiO2/C) derived from Streblus asper leaf wastes using a simple method. Dried Streblus asper leaves, which have plenty of biomass in Thailand, have a unique leaf texture due to their high SiO2 content. We can convert these worthless leaves into SiO2/C nanocomposites in one step, producing eco-materials with distinctive microstructures that influence electrochemical energy storage performance. Through nanostructured design, SiO2/C is thoroughly covered by a well-connected framework of conductive hybrid polymers based on the sodium alginate-polypyrrole (SA-PPy) network, exhibiting impressive morphology and performance. In addition, an excellent electrically conductive SA-PPy network binds to the SiO2/C particle surface through crosslinker bonding, creating a flexible porous space that effectively facilitates the SiO2 large volume expansion. At a current density of 0.3 C, this synthesized SA-PPy@Nano-SiO2/C anode provides a high specific capacity of 756 mAh g-1 over 350 cycles, accounting for 99.7% of the theoretical specific capacity. At the high current of 1 C (758 mA g-1), a superior sustained cycle life of over 500 cycles was evidenced, with over 93% capacity retention. The research also highlighted the potential for this approach to be scaled up for commercial production, which could have a significant impact on the sustainability of the lithium-ion battery industry. Overall, the development of green nanocomposites along with polymers having a distinctive structure is an exciting area of research that has the potential to address some of the key challenges associated with lithium-ion batteries, such as capacity degradation and safety concerns, while also promoting sustainability and reducing environmental impact.

Nanoporous Carbon Materials Derived from Zanthoxylum Bungeanum Peel and Seed for Electrochemical Supercapacitors.

In order to prepare biomass-derived carbon materials with high specific capacitance at a low activation temperature (≤700 °C), nanoporous carbon materials were prepared from zanthoxylum bungeanum peels and seeds via the pyrolysis and KOH-activation processes. The results show that the optimal activation temperatures are 700 °C and 600 °C for peels and seeds. Benefiting from the hierarchical pore structure (micropores, mesopores, and macropores), the abundant heteroatoms (N, S, and O) containing functional groups, and plentiful electrochemical active sites, the PAC-700 and SAC-600 derive the large capacities of ~211.0 and ~219.7 F g-1 at 1.0 A g-1 in 6 M KOH within the three-electrode configuration. Furthermore, the symmetrical supercapacitors display a high energy density of 22.9 and 22.4 Wh kg-1 at 7500 W kg-1 assembled with PAC-700 and SAC-600, along with exceptional capacitance retention of 99.1% and 93.4% over 10,000 cycles at 1.0 A g-1. More significantly, the contribution here will stimulate the extensive development of low-temperature activation processes and nanoporous carbon materials for electrochemical energy storage and beyond.

A hierarchical porous structure and nitrogen-doping jointly enhance the lithium-ion storage capacity of biomass-derived carbon materials

Biomass-derived carbon materials are considered potential lithium-ion anode materials because they are sustainable, renewable, economical, and environmentally friendly and have tunable microstructures. However, biomass-derived carbon materials have low specific capacity and show capacity degradation during long-term electrochemical cycling, which prevents their application in high-performance lithium-ion batteries. Hence, in this paper, nitrogen-doped hierarchical porous carbon (NHPC) is synthesized from a biomass waste material, corncob, through one-step activation and carbonization procedures. N-doping in the NHPC modifies the electron distribution on the surface of carbon, resulting in the generation of additional lithium-ion storage sites and enhancing electrode wettability to increase the conductivity. Additionally, the doping procedure results in a hierarchical porous structure with an increased specific surface area and pore volume, which facilitates ion transport and provides remarkable cycling stability. The electrochemical performance of NHPC is improved by the jointly beneficial combination of N-doping and the hierarchical porous structure. The optimized NHPC electrode provides a reversible specific capacity of 700 mAh g−1 after 100 cycles at 100 mA g−1. This study provides a simple and efficient method for improving the electrochemical properties of biomass-derived carbon materials through elemental doping and modulation of microscopic morphology and structure.

Electroadsorption Desalination Performance of Carbon Materials Derived from Coconut Shell without Membrane Separation

This study investigated coconut shells, an abundant and low-cost raw material, as the precursor for activated carbon preparation, and applied a carbonization activation method to prepare carbon materials under different activation conditions. The differences in the performance of biomass derived carbon materials as capacitive deionization (CDI) electrodes were studied under conditions of different activators, activator doses, and activation temperatures. Compared with commercial coconut shell activated carbon, studies have shown that biomass derived carbon electrodes obtained under the optimal preparation conditions of NaOH as the activator, a carbonizer to activator ratio of 1:3, and an activation temperature of 800 ℃ have an excellent electro adsorption performance and the potential to be used as a CDI electrode material. The salt adsorption capacity (SAC) of activated carbon made with coconut shell derived carbon materials after 20min of electro adsorption reached a maximum of 11.47mg/g. After 10 repeated uses, its SAC remained at the original 90.58%, demonstrating an excellent cycling stability.

Preparation of natural N/O/S co-doped biomass-derived carbon materials for supercapacitors using multistage gas self-exfoliation effect

High-value utilization of biomass provided a feasible way to solve the energy shortage and environmental problems. The preparation of micro-mesoporous composite carbon materials from biomass waste as feedstock using a multistage gas self-exfoliation mechanism (CH3COOK and Ca2(C2H5COO)2) was a feasible approach. Among them, the N, O and S co-doped carbon materials were obtained in this paper by using forestry waste (bamboo) as raw material, spiral algae as green heteroatom dopant, Ca2(C2H5COO)2 as multifunctional template agent, and CH3COOK as gentle activator. The results indicated that BC-SA-0.5CP exhibited 324.85 F/g at 0.5 A/g. The symmetric supercapacitor (BSC-0.5//BSC-0.5) achieved 96.02% capacitance retention after 10,000 cycles, indicating excellent rate performance and charge/discharge stability. At a power density of 162.5 W/kg, the BSC-0.5//BSC-0.5 had an energy density of 14.67 Wh/kg. In addition, it was deeply analyzed the growth mechanism of heteroatoms, the formation mechanism of porous carbon and the electron transfer routes, which provided a theoretical basis for the preparation of biomass-derived carbon materials. Overall, this study demonstrated that the multistage gas self-exfoliation mechanism was beneficial in promoting the formation of micro-mesoporous composite structures and the growth of heteroatom functional groups, which ultimately provided a new route for the synthesis of natural heteroatom-doped porous carbon.

Synthesis of natural oxygen-doped bamboo-derived hierarchical micro-mesoporous composite carbon materials using a green activation strategy

Utilizing biomass waste to synthesize hierarchical micro-mesoporous composite carbon materials for application in the field of supercapacitors realized green and sustainable energy development. This paper efficiently synthesized natural O-doped carbon materials using bamboo as biomass material by simple air pre-oxidation and secondary carbonization methods. Among them, KCl acted as a recyclable templating agent and flame retardant, facilitating the construction of mesoporous structures. The green activator CH3COOK promoted the generation of micropores. The combination of dual activation strategies (physical and chemical) contributed to the conversion of bamboo to hierarchical micro-mesoporous composite carbon materials. During pre-carbonization, air was used as a natural dopant which etched the carbon material and promoted the creation of oxygenated functional groups. The best carbon material exhibited an excellent electrochemical capacity of 321.65 F/g in 6 M KOH electrolyte. Furthermore, the symmetric supercapacitor exhibited high cycling stability (95.52 %) and outstanding power density. This work provided a new idea for preparing controllable biomass-derived carbon materials, while offering a reference for applying dual activation strategies in carbon material synthesis.

Preparation and electrochemical performance of cellulose-based biomass-derived carbon materials

Biomass-derived carbon materials are regarded as an ideal precursor for activated carbon owing to their unique structure, widely used in energy storage applications. Porous biomass carbon materials were prepared by high-temperature carbonization and activation methods using corn stalk stem pith as the carbon source. The structures and morphology of biomass-derived carbon materials were also characterized and analyzed, and it was employed as the electrode material to study the electrochemical properties. The results showed that the specific surface area and pore volume increased with the increase of temperature under the action of the same activator. The activation degree of carbon materials by different activators showed obvious differences under the same temperature conditions, and the structure and properties of the carbon materials obtained by sodium hydroxide activation were better than those obtained by sodium bicarbonate activation. When the temperature was fixed at 900 ℃, the carbon materials obtained by sodium hydroxide activation showed the best structural characteristics and electrochemical properties, with the specific surface area up to 532.881 m2·g−1 and the microporous volume accounting for 76.266 % of the total pore volume. By cyclic voltammetry test, the specific capacity was 139 F·g−1 at a scan rate of 10 mV·s−1, and the electrochemical impedance was much smaller than the impedance of the product obtained by sodium bicarbonate activation. Meanwhile, the specific capacity remained basically unchanged after 1000 cycles of charging and discharging, with excellent cycling stability and electrochemical performance. The relevant results provide a new way for the efficient utilization and functionalization of biomass resources.

Lignin organic molecule aggregate derived turbine-like nanocarbon with high nitrogen doping for potassium ion hybrid capacitors

Potassium-ion hybrid capacitors (PIHCs) represent a burgeoning class of electrochemical energy storage devices characterized by their remarkable energy and power densities. Utilizing amorphous carbon derived from sustainable biomass presents an economical and environmentally friendly option for anode material in high-rate potassium-ion storage applications. Nevertheless, the potassium-ion storage capacity of most biomass-derived carbon materials remains modest. Addressing this challenge, nitrogen doping engineering and the design of distinctive nanostructures emerge as effective strategies for enhancing the electrochemical performance of amorphous carbon anodes. Developing highly nitrogen-doped nanocarbon materials is a challenging task because most lignocellulosic biomasses lack nitrogen functional groups. In this work, we propose a general strategy for directly carbonizing supermolecule-mediated lignin organic molecular aggregate (OMA) to prepare highly nitrogen-doped biomass-derived nanocarbon. We obtained lignin-derived, highly nitrogen-doped turbine-like carbon (LNTC). Featuring a three-dimensional turbine-like structure composed of amorphous, thin carbon nanosheets, LNTC demonstrated a capacity of 377 mAh g−1 when used as the anode for PIHCs. This work also provides a new synthesis method for preparing highly nitrogen-doped nanocarbon materials derived from biomass.

Spatially confined CuFe2O4 nanosphere in N/O-codoped porous carbon mimetics for triple-mode sensing of antibiotics and visual detection of neurotransmitters in biofluids

BackgroundCarbon-based nanozymes have recently received enormous concern, however, there is still a huge challenge for inexpensive and large-scale synthesis of magnetic carbon-based “Two-in-One” mimics with both peroxidase (POD)-like and laccase-like activities, especially their potential applications in multi-mode sensing of antibiotics and neurotransmitters in biofluids. Although some progresses have been made in this field, the feasibility of biomass-derived carbon materials with both POD-like and laccase-like activities by polyatomic doping strategy is still unclear. In addition, multi-mode sensing platform can provide a more reliable result because of the self-validation, self-correction and mutual agreement. Nevertheless, the use of magnetic carbon-based nanozyme sensors for the multi-mode detection of antibiotics and neurotransmitters have not been investigated. ResultsWe herein report a shrimp shell-derived N, O-codoped porous carbon confined magnetic CuFe2O4 nanosphere with outstanding laccase-like and POD-like activities for triple-mode sensing of antibiotic d-penicillamine (D-PA) and chloramphenicol (CPL), as well as colorimetric detection of neurotransmitters in biofluids. The magnetic CuFe2O4/N, O-codoped porous carbon (MCNPC) armored mimetics was successfully fabricated using a combined in-situ coordination and high-temperature crystallization method. The synthesized MCNPC composite with superior POD-like activity can be used for colorimetric/temperature/smartphone-based triple-mode detection of D-PA and CPL in goat serum. Importantly, the MCNPC nanozyme can also be used for colorimetric analysis of dopamine and epinephrine in human urine. SignificanceThis work not only offered a novel strategy to large-scale, cheap synthesize magnetic carbon-based “Two-in-One” armored mimetics, but also established the highly sensitive and selective platforms for triple-mode monitoring D-PA and CPL, as well as colorimetric analysis of neurotransmitters in biofluids without any tanglesome sample pretreatment.

Green preparation of fiberboard waste derived N–doped carbon catalysts with tailored properties for efficient hydrogenation reduction of nitroaromatics

Biomass–derived carbon materials doped with diverse heteroatoms have demonstrated huge potentials for environment and energy applications, thanks to the availability, preferable porous and channel structures, and excellent conductivity and stability. In this work, fiberboard waste containing resin–based adhesive was selected for the green fabrication of N–doped carbon catalysts without using extra N–sources. A facile two–step calcination strategy with sequential carbonization and activation was proposed for generation and exposure of indispensable active sites, realizing the controllable regulation of textural and morphological characteristics. The resulting N–doped fiberboard derived carbon (NFC) samples possessed unique hierarchically porous structures with a significantly enlarged surface area, plentiful activity–dependent N species (e.g., graphitic N and pyridinic N), as well as suitable graphitization degree and surface hydrophilicity. As a result, a favorable adsorption procedure and an enhanced accessibility of active sites synergistically boosted the catalytic performance towards hydrogenation reduction of nitroaromatics. Taking the NFC–hh sample as paradigm, an excellent performance was demonstrated for 4–nitrophenol (4–NP) reduction, achieving a high apparent rate constant of 0.40 min−1 and an impressive turnover frequency of ∼0.20 mmol g−1 min−1. Besides, the continuous–flowing catalytic test exhibited an excellent conversion efficiency > 99.50% with a long–term stability over 100 h, showing an attractive prospect for industrial application. This work presents a new approach for high value–added utilization of biomass waste, and provides a low–cost and high–active catalyst for environmental remediation.

Exploring Carbonization Temperature to Create Closed Pores for Hard Carbon as High-Performance Sodium-Ion Battery Anodes.

Biomass-derived porous carbon materials are meaningful to employ as a hard carbon precursor for anode materials of sodium-ion batteries (SIBs) from a sustainability perspective. Here, a straightforward approach is proposed to develop rich closed pores in pinenut-derived carbon, with the aim of improving Na+ plateau storage by adjusting the pyrolysis temperature. The optimized sample, namely the pinenut-derived carbon at 1300 °C, demonstrates remarkable reversible specific capacity of 278 mAh g-1, along with a high initial Coulomb efficiency of 85% and robust cycling stability (with a capacity retention of 89% after 800 cycles at 0.2 A g-1). In situ and ex situ analyses unveil that the developed closed pores play a significant role in enhancing the plateau capacity, providing compelling evidence for the "adsorption-filling" mechanism. Moreover, the corresponding full-cell achieves a high energy density of 245.7Wh kg-1 (based on the total weight of both electrode active materials) and exhibits outstanding rate capability (191.4 mAh g-1 at 3 A g-1).

Interfacial regulation of biomass-derived carbon towards high-performance supercapacitor

Interfacial regulation for carbon-based materials plays critical role for supercapacitive performance improvement and the strategies about introducing heteroatomic groups and tuning specific surface area can be proposed to effectively address the low specific capacitance issues. Thus, the approaches about activation treatment with nitric acid (APC-H800) and copper chloride (APC-C800) for biomass-derived carbon materials have been raised and systematically investigated. Consequently, though the above chemical activation treatment, the oxygen and nitrogen functional groups can be introduced for APC-H800. Meanwhile, the specific surface area of APC-C800 has been significantly increased. Significantly, the upper specific capacitance of 384 F g−1 and 423 F g−1 for APC-H800 and APC-C800 electrodes can be achieved at a current density of 1.0 A g−1, what matters more is that two symmetric devices offer superior energy density and desirable cycling stability (no decrease that occurs after 10,000 cycles) are successfully assembled by employing APC-H800 and APC-C800 electrodes, respectively. More significantly, desirable energy density about 11.18 Wh kg−1 and 12.5 Wh kg−1 at 249.98 W kg−1 and 250 W kg−1 have been achieved for the symmetric supercapacitor devices of APC-H800//APC-H800 and APC-C800//APC-C800. These modification strategies shed insight into the sensible design of a further stage of advanced art carbon electrodes for powerful performance supercapacitors.

Fallen autumn leaves – The source of highly porous carbon for Zn-ion hybrid supercapacitors

Over the years, many sophisticated synthetic two-dimensional (2D) carbon materials have become increasingly popular for supercapacitors, e.g. zinc-ion hybrid supercapacitors (ZHSC) due to their ordered structure and high energy density. Additionally, ZHSC is a very demanding device, where finding efficient materials is challenging and the energy storage mechanism remains unclear. Biomass-derived carbon materials exhibit many drawbacks due to their impurities and defective structure, low stability and poor capacitance. In this study, a ZHSC was assembled via carbonization and activation of leaves collected from city streets and utilized as a cathode material. The AC650_Zn-foil presented a high specific capacitance of 95 F·g−1 and a high energy density of 86 W·h·kg−1 at 210 W·kg−1. Furthermore, a superior power density of 40,960 W·kg−1 at 33 W·h·g−1 was presented compared to other investigated materials. In addition, we identified the processes that occurred in the following device, which demonstrated a mechanism that determines the migration of Zn ions, as well as the chemical reactions involved in Zn ions.

Electromagnetic interference shielding using biomass-derived carbon materials

The growing concern over electromagnetic radiation (EMR) emitted by electronic devices has raised awareness of its adverse effects on human health and electronic operations, thus increasing interest in electromagnetic interference (EMI) shielding. Biomass-derived carbon materials (BCMs) provide effective and environmentally friendly solutions to address EMI-related issues. This review investigates the impressive EMI shielding efficiency achieved by various BCMs, that used in polymer composites, 3-D carbonaceous foams/aerogels, and building structural composites. The review outlines the primary mechanism of EMI shielding, the calculation of EMI shielding efficiency, and briefly discusses factors influencing shielding efficiency and production methods of BCMs based EMI shielding composites. It also evaluates the EMI shielding performance of biomass-derived carbon-based foams and aerogels. Finally, a concise overview of the future prospects for biomass-derived carbon EMI shield materials is presented.

A Review on the Upgradation of Biomass-derived Hard Carbon Materials

Abstract: Sodium-ion battery is a promising alternative to lithium-ion battery because of its abundant raw material resources, low price, and high specific capacity. Amorphous carbon materials (hard carbon) have micropores and impurities, facilitating the intercalation of sodium ions to form "quasi-metallic sodium," resulting in a high sodium storage capacity and a low sodium storage potential. Consequently, hard carbon is one of the most widely studied negative electrode materials. It can be prepared from biomass by thermochemical conversion and has the advantages of large specific capacity, low cost, good cycling stability, and renewability. This review focuses on the recent advances in biomass-based hard carbon materials. Firstly, the preparation methods of hard carbon, including precursor selection, pretreatment, drying methods, and carbonization processes, are summarized. Secondly, the effects of precursor composition and heteroatom doping structure and properties of hard carbon are examined, and the changes in carbon material pores during the activation process, as well as the selection of optimal drying method, pyrolysis temperature, carbonization temperature, activator dosage, and additive, are discussed. Thirdly, the impact of preparation methods on hard carbon's cost, efficiency, and stability is briefly summarized, and the relevant improvement measures and prospects are proposed. Finally, some insights are provided into preparing highperformance biomass-based anode materials for sodium-ion batteries.

Structural regulation of ultra-microporous biomass-derived carbon materials induced by molten salt synergistic activation and its application in CO2 capture

The development of high-performance biomass-based carbon materials for CO2 adsorption is considered to be a promising strategy due to the advantages of renewable raw materials, energy efficiency, and easy operation. Herein, two molten salt systems, KHCO3-KCl and K2CO3-KCl, are used to prepare corn stalk-based porous carbon. The KHAC-KCl with ultra-high specific surface area of 2512 m2/g and rich ultra-microporous structure is successfully prepared when the KHCO3-KCl system is used. Series characterization methods are used to explore the influence of molten salt systems on the physicochemical properties of materials. It is found that both molten salt systems can significantly increase the oxygen-containing functional groups in carbon materials. The difference is that the KHCO3-KCl system can significantly increase the ultra-micropore proportion (48.6 % to 66.2 %) and the specific surface area (1551 m2/g to 2512 m2/g), while the K2CO3-KCl system cannot. Mechanism study shows that the KHCO3-KCl system can significantly affect the interaction between the pyrolysis reactions of the three components of lignocellulose, thereby regulating the physical and chemical properties of the material to achieve synergistic activation. CO2 adsorption studies show that KHAC-KCl exhibits excellent CO2 adsorption properties, reaching a high adsorption capacity of 7.3 mmol/g and 3.6 mmol/g at 273 K and 298 K, respectively. Furthermore, the material exhibits suitable Qst value (20–40 KJ/mol), high CO2/N2 selectivity (35 at 273 K and 22 at 298 K) and excellent cycling stability. This work can provide guidance for the preparation of low-cost and efficient CO2 adsorbents from renewable biomass.

Economical and shape-stabilized hydrated salt/bagasse biomass-derived carbon phase change composite for thermal energy storage

Due to their high heat storage density, low cost, and non-inflammability, hydrated salts have significant potential for application in thermal energy storage for buildings. Hydrated salts, however, have a few drawbacks, including high supercooling degree, unstable shape, and phase separation. In general, materials such as graphite, aerogel, and foam metal are commonly used to provide support for hydrated salts in order to mitigate or eliminate their drawbacks. While these currently used supporting materials have expensive and complicated production procedures. In this study, we developed bagasse biomass-derived carbon (BBC) materials to obtain easily accessible, cost-effective, and environmentally friendly support materials. Using the high-temperature carbonization method, the bagasse made from biological waste displayed a highly oriented and stacked lamellar structure. This not only significantly lowered the cost but also made the storage of hydrated salts easier. A straightforward vacuum impregnation technique was used to create SSD-SC/BBC phase change composites (PCCs). In comparison to sodium sulfate decahydrate (SSD), the developed SSD-SC/BBC9 PCCs exhibited a higher thermal storage capacity of 161.5 J/g, along with an exceptionally low supercooling degree. They also demonstrated the higher thermal conductivity of 1.79 W·m−1·K−1, improved thermal reliability, and enhanced solar-thermal energy conversion ability. Compared to other support materials, the economic analysis using static and dynamic payback periods demonstrates that the utilization of biomass-derived carbon as a support material for phase change materials (PCMs) is cost-effective, with lower preparation costs and a shorter payback period. A simple, affordable, and environmentally friendly method for utilizing hydrated salts in thermal energy storage for buildings is provided by SSD-SC/BBC9 PCCs.

Biomass-Derived Carbon Materials for Electrochemical Energy Storage.

The environmental impact from the waste disposal has been widely concerned around the world. The conversion of wastes to useful resources is important for the sustainable society. As a typical family of wastes, biomass materials basically composed of collagen, protein and lignin are considered as useful resources for recycle and reuse. In recent years, the development of carbon material derived from biomasses, such as plants, crops, animals and their application in electrochemical energy storage have attracted extensive attention. Through the selection of the appropriate biomass, the optimization of the activation method and the control of the pyrolysis temperatures, carbon materials with desired features, such as high-specific surface area, variable porous framework, and controllable heteroatom-doping have been fabricated. Herein, this review summarized the preparation methods, morphologies, heteroatoms doping in the plant/animal-derived carbonaceous materials, and their application as electrode materials for secondary batteries and supercapacitors, and as electrode support for lithium-sulfur batteries. The challenges and prospects for the controllable synthesis and large-scale application of biomass-derived carbonaceous materials have also been outlooked.

Towards Negative Emissions: Hydrothermal Carbonization of Biomass for Sustainable Carbon Materials.

The contemporary production of carbon materials heavily relies on fossil fuels, contributing significantly to the greenhouse effect. Biomass is a carbon-neutral resource whose organic carbon is formed from atmospheric CO2. Employing biomass as a precursor for synthetic carbon materials can fix atmospheric CO2 into solid materials, achieving negative carbon emissions. Hydrothermal carbonization (HTC) presents an attractive method for converting biomass into carbon materials, by which biomass can be transformed into materials with favorable properties in a distinct hydrothermal environment, and these carbon materials have made extensive progress in many fields. However, the HTC of biomass is a complex and interdisciplinary problem, involving simultaneously the physical properties of the underlying biomass and sub/supercritical water, the chemical mechanisms of hydrothermal synthesis, diverse applications of resulting carbon materials, and the sustainability of the entire technological routes. This review starts with the analysis of biomass composition and distinctive characteristics of the hydrothermal environment. Then, the factors influencing the HTC of biomass, the reaction mechanism, and the properties of resulting carbon materials are discussed in depth, especially the different formation mechanisms of primary and secondary hydrochars. Furthermore, the application and sustainability of biomass-derived carbon materials are summarized, and some insights into future directions are provided.