Superior Lithium-Ion Storage at Room and Elevated Temperature in an Industrial Woodchip Derived Porous Carbon

Progress on Separation and Hydrothermal Carbonization of Rice Husk Toward Environmental Applications

Owing to the increasing global demand for carbon resources, pressure on finite materials, including petroleum and inorganic resources, is expected to increase in the future. Efficient utilization of waste resources has become crucial for sustainable resource acquisition for creating the next generation of industries. Rice husks, which are abundant worldwide as agricultural waste, are a rich carbon source with a high silica content and have the potential to be an effective raw material for energy-related and environmental purification materials such as battery, catalyst, and adsorbent. Converting these into valuable resources often requires separation and carbonization; however, these processes incur significant energy losses, which may offset the benefits of using biomass resources in the process steps. This review summarizes and discusses the high value of RHs, which are abundant as agricultural waste. Technologies for separating and converting RHs into valuable resources by hydrothermal carbonization are summarized based on the energy efficiency of the process.

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.

Sustainable Battery Materials from Biomass

Sustainable sources of energy have been identified as a possible way out of today's oil dependency and are being rapidly developed. In contrast, storage of energy to a large extent still relies on heavy metals in batteries. Especially when built from biomass-derived organics, organic batteries are promising alternatives and pave the way towards truly sustainable energy storage. First described in 2008, research on biomass-derived electrodes has been taken up by a multitude of researchers worldwide. Nowadays, in principle, electrodes in batteries could be composed of all kinds of carbonized and noncarbonized biomass: On one hand, all kinds of (waste) biomass may be carbonized and used in anodes of lithium- or sodium-ion batteries, cathodes in metal-sulfur or metal-oxygen batteries, or as conductive additives. On the other hand, a plethora of biomolecules, such as quinones, flavins, or carboxylates, contain redox-active groups that can be used as redox-active components in electrodes with very little chemical modification. Biomass-based binders can replace toxic halogenated commercial binders to enable a truly sustainable future of energy storage devices. Besides the electrodes, electrolytes and separators may also be synthesized from biomass. In this Review, recent research progress in this rapidly emerging field is summarized with a focus on potentially fully biowaste-derived batteries.

Materials by Design: Tailored Morphology and Structures of Carbon Anodes for Enhanced Battery Safety

Next-generation Li-ion battery technology awaits materials that not only store more electrochemical energy at finite rates but also exhibit superior control over side reactions and better thermal stability. Herein, we hypothesize that designing an appropriate particle morphology can provide a well-balanced set of physicochemical interactions. Given the anode-centric nature of primary degradation modes, we investigate three different carbon particles-commercial graphite, spherical carbon, and spiky carbon-and analyze the correlation between particle geometry and functionality. Intercalation dynamics, side reaction rates, self-heating, and thermal abuse behavior have been studied. It is revealed that the spherical particle outperforms an irregular one (commercial graphite) under thermal abuse conditions, as it eliminates unstructured inhomogeneities. A spiky particle with ordered protrusions exhibits smaller intercalation resistance and attenuated side reactions, thus outlining the benefits of controlled stochasticity. Such findings emphasize the importance of tailoring particle morphology to proffer selectivity among multimodal interactions.

Lightweight and efficient microwave absorbing materials based on walnut shell-derived nano-porous carbon

Lightweight microwave absorbing materials have drawn tremendous attention. Herein, nano-porous biomass carbon materials have been prepared by carbonization with a subsequent potassium hydroxide activation of walnut shells and the microwave absorption properties have also been investigated. The obtained samples have large specific surface areas with numerous micropores and nanopores. The sample activated at 600 °C with a specific surface area of 736.2 m² g^-1 exhibits the most enhanced microwave absorption performance. It has the maximum reflection loss of -42.4 dB at 8.88 GHz and the effective absorption bandwidth (reflection loss below -10 dB) is 1.76 GHz (from 8.08 GHz to 9.84 GHz), corresponding to a thickness of 2 mm. Additionally, the effective absorption bandwidth can reach 2.24 GHz (from 10.48 GHz to 12.72 GHz) when the absorber thickness is 1.5 mm. Three-dimensional porous architecture, interfacial polarization relaxation loss, and the dipolar relaxation loss make a great contribution to the excellent microwave absorption performance. In contrast, the non-activated sample with lower specific surface area (435.3 m² g^-1) has poor microwave absorption performance due to a poor dielectric loss capacity. This comparison highlights the role of micropores and nanopores in improving the dielectric loss property of porous carbon materials. To sum up, porous biomass carbon has great potential to become lightweight microwave absorbers. Moreover, KOH is an efficient activation agent in the fabrication of carbonaceous materials.

Controlled Growth of Nanostructured Biotemplates with Cobalt and Nitrogen Codoping as a Binderless Lithium-Ion Battery Anode

Biomass can serve as a sustainable template for the synthesis of carbon materials but is limited by the intrinsic properties of the precursor organism. In this study we demonstrate that the properties of a fungal biotemplate can be tuned during cultivation, establishing a new electrode manufacturing process and ultimately improving the electrochemical performance of the biomass-derived electrode. More specifically, the carbon/nitrogen ratio of Neurospora crassa mycelia mats was shifted by 5-fold while generating cobalt nanoparticles into the hyphal structure originating from macroconidia spores. This shift was achieved through nitrate limitation and equal molar concentrations of Mg²⁺ and Co²⁺ in the growth media. The resulting mycelia mat was converted via a high-temperature pyrolysis process (800 °C) to produce a freestanding cobalt and nitrogen codoped electrode material with no postmodification. Ultimately, nitrogen doping resulted in one of the highest recorded specific reversible capacity for a freestanding biomass-derived lithium-ion anode (400 mAh g^-1 at C/10). We observed an additional improvement in capacity to 425 mAh g^-1 with the incorporation of 3 wt % Co. Our results show how shaping the chemical characteristics of an electrode during the growth of the biotemplate allows for sustainable carbon-based material manufacturing from a living (self-assembled) material.