Assembly and electrochemical testing of renewable carbon-based anodes in SIBs: a practical guide

Sodium-ion batteries (SIBs) are considered as a promising candidate to replace lithium-ion batteries (LIBs) in large-scale energy storage applications. Abundant sodium resources and similar working principles make this technology attractive to be implemented in the near future. However, the development of high-performance carbon anodes is a focal point to the upcoming success of SIBs in terms of power density, cycling stability, and lifespan. Fundamental knowledge in electrochemical and physicochemical techniques is required to properly evaluate the anode performance and move it in the right direction. This review aims at providing a comprehensive guideline to help researchers from different backgrounds (e.g., nanomaterials and thermochemistry) to delve into this topic. The main components, lab configurations, procedures, and working principles of SIBs are summarized. Moreover, a detailed description of the most used electrochemical and physicochemical techniques to characterize electrochemically active materials is provided

Adsorption performance of physically activated biochars for postcombustion Co2 capture from dry and humid flue gas

In the present study, the performance of four biomass-derived physically activated biochars for dynamic CO2 capture was assessed. Biochars were first produced from vine shoots and wheat straw pellets through slow pyrolysis (at pressures of 0.1 and 0.5 MPa) and then activated with CO2 (at 0.1 MPa and 800 C) up to different degrees of burn-off. Cyclic adsorption-desorption measurements were conducted under both dry and humid conditions using a packed-bed of adsorbent at relatively short residence times of the gas phase (12-13 s). The adsorbent prepared from the vine shoots-derived biochar obtained by atmospheric pyrolysis, which showed the most hierarchical pore size distribution, exhibited a good and stable performance under dry conditions and at an adsorption temperature of 50 C, due to the enhanced CO2 adsorption and desorption rates. However, the presence of relatively high concentrations of water vapor in the feeding gas clearly interfered with the CO2 adsorption mechanism, leading to significantly shorter breakthrough times. In this case, the highest percentages of a used bed were achieved by one of the other activated biochars tested, which was prepared from the wheat straw-derived biochar obtained by pressurized pyrolysis

Biochar production through slow pyrolysis of different biomass materials: Seeking the best operating conditions

In the last years, special attention has been focused on analyzing the effect of pyrolysis conditions (mainly peak temperature) on the yield and properties of produced biochar. Given that the nature of biomass plays a key role in the pyrolysis process, it becomes really difficult to establish generic trends and correlations, which can be used for any biomass feedstock to predict the properties of derived biochar. Thus, more experimental studies focused on a given biomass source are still needed with the aim of providing reliable data for further research goals. In addition, a number of techniques have been proposed to estimate the long-term stability of biochar in a relatively easy and fast way (e.g., recalcitrance index, percentage of aromatic carbon, H2O2 oxidation, etc.). Please click on the file below for full content of the abstract

Using a Fixed-Bed of Wheat Straw-Derived Biochar to Enhance Cracking of a Mixture of Four Pyrolysis Vapor Model Compounds

The aim of this work is to test the capacity of a biochar-based porous material to enhance the cracking of pyrolysis vapors. Biochar is a sustainable material obtained from renewable resources and a relatively low cost alternative to the metal-containing catalysts used in catalytic cracking

Operating Conditions Affecting the Behavior of Wheat Straw Pellets During Slow Pyrolysis Process: a Full Insight

A deep study on the effects of absolute pressure, peak temperature, gas residence time and gas atmosphere on the pyrolysis behaviour of wheat straw pellets in a bench-scale fixed-bed reactor has been carried out

Vine Shoots-Derived Hard Carbons as Anodes for Sodium-Ion Batteries: Role of Annealing Temperature in Regulating Their Structure and Morphology

Sodium‐ion batteries (SIBs) are considered one of the most promising large‐scale and low‐cost energy storage systems due to the abundance and low price of sodium. Herein, hard carbons from a sustainable biomass feedstock (vine shoots) were synthesized via a simple two‐step carbonization process at different highest temperatures to be used as anodes in SIBs. The hard carbon produced at 1200 °C delivered the highest reversible capacity (270 mAh g−1 at 0.03 A g−1, with an acceptable initial coulombic efficiency of 71 %) since a suitable balance between the pseudographitic domains growth and the retention of microporosity, defects, and functional groups was achieved. A prominent cycling stability with a capacity retention of 97 % over 315 cycles was also attained. Comprehensive characterization unraveled a three‐stage sodium storage mechanism based on adsorption, intercalation, and filling of pores. A remarkable specific capacity underestimation of up to 38 % was also found when a two‐electrode half‐cell configuration was employed to measure the rate performance. To avoid this systematic error caused by the counter/reference electrode polarization, we strongly recommend the use of a three‐electrode setup or a full‐cell configuration to correctly evaluate the anode response at moderate and high current rates

Effects of slow-pyrolysis conditions on the products yields and properties and on exergy efficiency: A comprehensive assessment for wheat straw

In the present work, the effects of the peak temperature (400–550 °C), absolute pressure (0.2–0.9 MPa), gas residence time (100–200 s) and reactor atmosphere (pure N2 or a mixture of CO2/N2) on the pyrolysis behavior of wheat straw pellets were investigated. A factorial design of experiments was adopted to assess the effects of the above-mentioned factors on the pyrolysis products, the exergy efficiencies related to them and to the overall process, and the heat required. The pyrolysis energy/exergy assessment is nowadays of great interest, for the scaling of the installations from lab-scale to commercial-scale. Results showed that, as expected, the peak temperature was the most influential factor on the yields and distributions of all the pyrolysis products as well as the char properties related to its potential stability and pore size distribution. However, an increased pressure enhanced the release of the gas species at the expense of the liquid products, without altering the final char yield. The char exergy efficiency was negatively affected by an increase in peak temperature, whereas its effect on the exergy efficiency of the produced gas resulted to be positive. It was also found that pressurized pyrolysis favored the exergy efficiency of the process, even at relatively high pyrolysis peak temperature. For the biomass feedstock and the range of operating conditions studied here, thermodynamic irreversibilities of the pyrolysis system were considerably lowered when the process was conducted at 550 °C, 0.9 MPa and using a mixture of CO2 and N2 as carrier gas at relatively short residence times

PRODUCCIÓN Y CARACTERIZACIÓN DE BIOCHAR DERIVADO DE SARMIENTO DE VIÑA (Vitis vinifera). ESTUDIO PRELIMINAR DE SU APLICACIÓN SOBRE EL DESARROLLO DE PLANTAS GRAMÍNEAS.

La utilización de biochar como enmienda orgánica en el suelo es una de las aplicaciones que ofrece este material. Muchos trabajos de investigación han confirmado la mejora de las propiedades del suelo con la adición de biochar, estimulando el desarrollo de los cultivos y el secuestro de carbono en el suelo. Se requiere todavía de mucha investigación y desarrollo para conocer las características específicas de cada biomasa de biochar y su posible influencia sobre el sistema suelo-planta-microorganismos. El presente estudio realiza un análisis sobre las características físico-químicas básicas y mecánicas del biochar de sarmiento, y un primer acercamiento sobre su aplicación e influencia sobre cultivos de gramíneas. La caracterización mecánica pretende conocer su comportamiento en el momento de su aplicación sobre el suelo mediante el uso de maquinaria agraria. Destacar que esta caracterización es novedosa, debido a que no existe otro estudio que presente este tipo de información. De los resultados obtenidos, lo más relevante ha sido que la temperatura de pirólisis afecta a los factores físicos del biochar, haciendo que sus características, tales como tamaño, longitud y factor de forma, varíen y tengan un comportamiento diferente en el momento de su aplicación

Study of the Influence of Pyrolysis Conditions on the Textural Properties of Physically Activated Biochars

Nine wheat straw-derived biochars were produced under different pyrolysis conditions (i.e. peak temperature, absolute pressure, and pyrolysis atmosphere) and subsequentially activated with CO2 at 800 °C in order to study the influence of the pyrolysis operating conditions on the textural properties of the resulting activated biochars

Hard carbons from waste hemp via hydrothermal carbonization with mil chemical activation for sodium–ion batteries

Owing to its wide availability and low cost, sodium-ion batteries (SIBs) appear as a very promising option for post-lithium energy storage systems. However, commercial graphite anodes used in lithium-ion batteries are not suitable for SIBs, due to a difficult insertion of sodium ions into the graphitic layers. Possible anode candidates focus on hard carbons (HCs). Here, HCs were synthesized from waste hemp hurd (WHH) via hydrothermal pretreatment (with either heteroatom doping or K2CO3 activation) and subsequent carbonization under Ar at 800 or 1000 °C. Regarding mild chemically activated HCs, the best material (exhibiting a 76% ICE and impressive reversible charge capacities of 354 and 77 mA h g–1 at 0.1 and 2 A g–1, respectively) was the carbon produced via hydrothermal preatretment in HCl aqueous solution and subsequently heated up to 1000 °C. However, poor cycling stability was observed for the last material, suggesting that some irreversible sodiation processes can take place