Formation mechanism and characterization of porous biomass carbon for excellent performance lithium-ion batteries

Blackberry Seeds-Derived Carbon as Stable Anodes for Lithium-Ion Batteries

The suitability of biocarbons derived from blackberry seeds as anode materials in lithium-ion batteries has been assessed for the first time. Blackberry seeds have antibacterial, anticancer, antidysentery, antidiabetic, antidiarrheal, and potent antioxidant properties and are generally used for herbal medical purposes. Carbon is extracted from blackberries using a straightforward carbonization technique and activated with KOH at temperatures 700, 800, and 900 °C. The physical characterization demonstrates that activated blackberry seeds-derived carbon at 900 °C (ABBSC-900 °C) have well-ordered graphene sheets with high defects compared to the ABBSC-700 °C and ABBSC-800 °C. It is discovered that an ABBSC-900 °C is mesoporous, with a notable Brunauer-Emmett-Teller surface area of 65 m2 g-1. ABBSC-900 has good electrochemical characteristics, as studied under 100 and 1000 mA g-1 discharge conditions when used as a lithium intercalating anode. Delivered against a 500 mA g-1 current density, a steady reversible capacity of 482 mA h g-1 has been achieved even after 200 cycles. It is thought that disordered mesoporous carbon with a large surface area account for the improved electrochemical characteristics of the ABBSC-900 anode compared to the other ABBSC-700 and ABBSC-800 carbons. The research shows how to use a waste product, ABBSC, as the most desired anode for energy storage applications.

Fungus-Based MnO/Porous Carbon Nanohybrid as Efficient Laccase Mimic for Oxygen Reduction Catalysis and Hydroquinone Detection

Developing efficient laccase-mimicking nanozymes via a facile and sustainable strategy is intriguing in environmental sensing and fuel cells. In our work, a MnO/porous carbon (MnO/PC) nanohybrid based on fungus was synthesized via a facile carbonization route. The nanohybrid was found to possess excellent laccase-mimicking activity using 2,2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) as the substrate. Compared with the natural laccase and reported nanozymes, the MnO/PC nanozyme had much lower K_m value. Furthermore, the electrochemical results show that the MnO/PC nanozyme had high electrocatalytic activity toward the oxygen reduction reaction (ORR) when it was modified on the electrode. The hybrid nanozyme could catalyze the four-electron ORR, similar to natural laccase. Moreover, hydroquinone (HQ) induced the reduction of oxABTS and caused the green color to fade, which provided colorimetric detection of HQ. A desirable linear relationship (0–50 μM) and detection limit (0.5 μM) were obtained. Our work opens a simple and sustainable avenue to develop a carbon–metal hybrid nanozyme in environment and energy applications.

Biomass-Based Silicon and Carbon for Lithium-Ion Battery Anodes

Lithium-ion batteries (LIBs) are the most preferred energy storage devices today for many high-performance applications. Recently, concerns about global warming and climate change have increased the need and requirements for LIBs used in electric vehicles, and thus more advanced technologies and materials are urgently needed. Among the anode materials under development, silicon (Si) has been considered the most promising anode candidate for the next generation LIBs to replace the widely used graphite. Si cannot be used as such as the electrode of LIB, and thus, carbon is commonly used to realize the applicability of Si in LIBs. Typically, this means forming a-Si/carbon composite (Si/C). One of the main challenges in the industrial development of high-performance LIBs is to exploit low-cost, environmentally benign, sustainable, and renewable chemicals and materials. In this regard, bio-based Si and carbon are favorable to address the challenge assuming that the performance of the LIB anode is not compromised. The present review paper focuses on the development of Si and carbon anodes derived from various types of biogenic sources, particularly from plant-derived biomass resources. An overview of the biomass precursors, process/extraction methods for producing Si and carbon, the critical physicochemical properties influencing the lithium storage in LIBs, and how they affect the electrochemical performance are highlighted. The review paper also discusses the current research challenges and prospects of biomass-derived materials in developing advanced battery materials.

Utilizing waste duckweed from phytoremediation to synthesize highly efficient FeNxC catalysts for oxygen reduction reaction electrocatalysis

Duckweed is a universal aquatic plant to remove nitrogen source pollutants in the field of phytoremediation. Due to the naturally abundant nitrogen, synthesis of carbon materials from duckweed would be a high-value approach. In oxygen reduction reaction (ORR) of metal-air batteries and fuel cells, non-noble metals and heteroatoms co-doped electrocatalysts with excellent catalytic activity and remarkable stability are promising substitutes for Pt-based catalysts. The first-class ORR performance is determined by appropriate pore structure and active sites, which are strongly associated with the feasible synthesis methods. Herein, a facile one-step synthesis strategy for the transition metals- and nitrogen-codoped carbon (MN_xC) based catalysts with hierarchically porous structure was developed. The MN_xC (M = Fe, Co, Ni, and Mn) active sites were constructed and FeN_xC (D-ZB-Fe) was the best electrocatalyst with excellent ORR performance. Results showed that D-ZB-Fe exhibited an obvious honeycomb porous structure with specific surface area of 1342.91 m²·g^-1 and total pore volume of 1.085 cm³·g^-1. It also possessed considerable active atoms and sites, where the proportion of pyridine N and graphite N was up to 72.9%. The above feature made for a superior ORR electrocatalytic activity. In specific, the onset and half-wave potential were 0.974 V and 0.857 V vs. RHE (Reversible Hydrogen Electrode), respectively. When compared with performances of commercial Pt/C, the four-electron pathway and relatively low peroxide yield, ca. 5%, were almost equivalent. Furthermore, D-ZB-Fe showed an excellent stability and remarkably methanol tolerance by the durability test. In conclusion, this research provides a new synthesis strategy of electrocatalysts with porous structures and active sites.

Efficient Toluene Adsorption on Metal Salt-Activated Porous Carbons Derived from Low-Cost Biomass: A Discussion of Mechanism

Porous carbons (PCS) derived from sodium lignin sulfonate were activated by four common metal salts. The samples exhibit distinct characteristics of irregular, sunflower-like, interconnected sheet, and tine block morphologies under the impact of NaCl, CaCl₂, ZnCl₂, and FeCl₃, respectively (PCS-MCl _x ). Surprisingly, the maximum and minimum specific surface areas are 1524 and 44 m²/g corresponding to PCS-ZnCl₂ and PCS-NaCl. All of the samples have plentiful functional groups; herein, PCS-NaCl and PCS-FeCl₃ are detected with the highest O and S contents (11.85, 1.08%), respectively, which signifies sufficient active sites for adsorption. These porous materials were applied in toluene adsorption from paraffin liquid and matched the Langmuir isotherm models well. Thus, the activation mechanism was discussed in detail. PCS-MCl _x has a completely different pyrolysis behavior according to thermogravimetry/derivative thermogravimetry (TG/DTG) analysis. It is speculated that H[ZnCl₂(OH)] would have an etching effect on the carbon structure of PCS-ZnCl₂, and HCl or H₂SO₄, resulting from FeCl₃ hydrolysis and a reduction reaction, would be corrosive to the sodium lignin sulfonate (SLS) surface. Each metal salt plays a different role in activation. The devised method for the synthesis of porous carbons is green and economical, which is suited to mass production.

Hydrothermal Synthesis of Cellulose-Derived Carbon Nanospheres from Corn Straw as Anode Materials for Lithium ion Batteries

As a most attractive renewable resource, biomass has the advantages of low pollution, wide distribution and abundant resources, promoting its applications in lithium ion batteries (LIBs). Herein, cellulose-derived carbon nanospheres (CCS) were successfully synthesized by hydrothermal carbonization (HTC) from corn straw for use as an anode in LIBs. The uniform distribution and cross-linked structure of carbon nanospheres were obtained by carefully controlling reaction time, which could not only decrease the transport pathway of lithium ions, but also reduce the structural damage caused by the intercalation of lithium ions. Especially, obtained after hydrothermal carbonization for 36 h, those typical characteristics make it deliver excellent cycling stability as well as the notable specific capacity of 577 mA h g-1 after 100 cycles at 0.2C. Hence, this efficient and environment-friendly method for the fabrication of CCS from corn straw could realize the secondary utilization of biomass waste, as well as serve as a new choice for LIBs anode materials.