Physicochemical properties of heterogeneous cellulose—solvent systems

Захаров, А. Г.; Прусов, А. Н.

doi:10.1007/s10692-006-0086-0

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…Now, we have to figure out the specificity, if any, of the CMC−Si interaction, and how it allows the conservation of the electrode texture and electrical wiring despite repeated breath and consequent back and forth changes in volume. Owing to the presence of polar groups, it is well documented that carbohydrates-based polymers undergo many inter- and intrachain hydrogen interactions , and that the extent and dynamic of interactions with the polar surface depend on the presence of water or mechanical stress . Various substitution of the OH groups can be applied in order to modify the nature and strength of these interactions, as suggested by Hochgatterer et al In order to obtain a better understanding of the nature of the interaction and behavior with respect to the Si−Li reaction, several approaches have been pursued enlisting modifications of (1) the polymer and (2) the Si surface.…”

Section: Resultsmentioning

confidence: 99%

Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries

et al. 2009

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Various Si/carbon/polymer composite electrodes were prepared to better understand the influence of the Si−polymer interactions on the stability of the Li−Si reaction and especially the superior performances of CMC-based (carboxy−methyl−cellulose) composites despite the large volume changes of the Si particles upon cycling. Via the modification of the composites formulation, the nature of the polymer, the nature and the amount of the substituting groups and the surface chemistry of the Si particles, together with the use of various characterization techniques (TEM, SEM, NMR−MAS, infrared spectroscopy, TGA, etc.) we could propose that the performances of the Si/Csp/CMC composite electrodes are nested in both the porous texture of the electrode and in the nature of the Si−polymer chemical bonding. A self-healing process of the rather strong Si−CMC hydrogen bonding which can accommodate textural stresses and can evolve during cycling is proposed to be critical for Si-based electrode performances. This better understanding leads to the design of Si-based electrodes with capacity retention reaching 1000 mAh/g of composite (i.e., full Si capacity) for at least 100 cycles and with a Coulombic efficiency close to 99.9% per cycle. Owing to these new aspects, we have now a deeper insight of the specific effects of the CMC binder, than could be successfully extended to other metals (Sn, Ge, Sb).

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Section: Resultsmentioning

confidence: 99%

Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries

et al. 2009

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“…28 Generally, depending on the presence of water and mechanical stress, polymeric carbohydrates undergo various inter-and intra-chain interactions forming hydrogen bonds due to the numerous polar groups in their structure. [29][30][31] Thermal stability of Na CMC is strongly dependent on its dissociation degree and the presence of intraand intermolecular bonding. 32 This would explain why the thermal properties of individual electrode components with the electrolyte are different from those of the composite electrode when in contact with the same electrolyte.…”

Section: Resultsmentioning

confidence: 99%

Thermally Induced Reactions between Lithiated Nano-Silicon Electrode and Electrolyte for Lithium-Ion Batteries

Profatilova

Langer

Badillo

et al. 2012

J. Electrochem. Soc.

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The thermal stability of nano-silicon electrodes before and after lithiation was studied by means of differential scanning calorimetry (DSC). It was found that pristine Si electrodes heated in presence of EC/DEC 1M LiPF 6 electrolyte show exothermic reactions between sodium carboxymethylcellulose (Na CMC binder) and LiPF 6 . The products of thermal decomposition of a lithiated nano-Si electrode with electrolyte at different temperatures were identified using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). SEI layer was found to be responsible for the thermal reactions in the range between 77 and 107 • C. Exothermic events between 107 and 140 • C were caused by partial decomposition of LiPF 6 salt, which products initiated further transformations of SEI layer compounds and esterification of Na CMC. Interaction between nano-Li x Si and EC/DEC 1M LiPF 6 was the reason for the main exothermic peaks at temperatures between 150 and 300 • C. Nano-Li x Si heated with EC/DEC solvent mixture without LiPF 6 resulted in electrolyte decomposition at much lower temperatures (>105 • C). Therefore, the important role of LiPF 6 in the thermal stabilization of nano-Li x Si with electrolyte at temperatures <140 • C was confirmed while LiTFSI salt added to EC/DEC was ineffective in the prevention of the main exothermic reaction starting at 105 • C.

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“…Because of the presence of polar groups, it is well-demonstrated that cellulose-based polymers undergo many inter- and intrachain hydrogen-bonding interactions. , Larcher et al suggested that hydrogen bonding enables a self-healing effect, which consequently preserves the electronic conductive path within the Si-based electrodes . This result manifests the importance of robust polymer chain networks constructed within the electrode.…”

Section: Establishing Mechanically Robust Electrodesmentioning

confidence: 99%

Establishing a Resilient Conductive Binding Network for Si-Based Anodes via Molecular Engineering

et al. 2022

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Metrics & MoreArticle Recommendations CONSPECTUS: Silicon-based anode materials have become a research hot spot as the most promising candidates for next-generation high-capacity lithium-ion batteries. However, the irreversible degradation of the conductive network in the anode and the resultant dramatic capacity loss have become two ultimate challenges that stem from inherent characteristics of the Si-based materials, including poor conductivity and massive volume changes (up to 300%) during cycling. Apart from optimization of the active materials, one effective way to stabilize high-capacity Sibased anodes is by designing polymeric binders to reinforce the conductive networks during repeated charge and discharge processes. As an inactive component in the electrode, the binder not only holds other components (e.g., active materials, conductive agents, and current collectors) together to maintain the mechanical integrity of the electrode but also serves as a thickener to facilitate the homogeneous distribution of particles. Therefore, binders play a key role in Si-based anodes by maintaining the integrity of conductive networks in the electrode.In this Account, on the basis of the extensive binder-related work on Si-based anodes since the 2000s, efforts made on maintaining the conductive network can be categorized into two main strategies: (1) stabilization of the primary conductive network (which generally refers to conductive agents) by enhancing the binding strength and resilience of the binding between electrode components (i.e., Si particles, conducting agents, and current collectors) via various interactions (e.g., dipolar interactions and covalent bonds) and (2) construction of the secondary conductive network by employing conductive binders, which serve as a molecular-level conductive layer on active materials. In this sense, functional groups in binders can be divided into two categories: mechanical structural units and conductive structural units. On the one hand, functional groups with strong polarities (e.g., −OH, −COOH, −NH 2, and −CONH−) generally serve as binding structural units because of their bonding tendencies; on the other hand, exhibiting high electronic conductivity, conjugated functional groups (e.g.

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Physicochemical properties of heterogeneous cellulose—solvent systems

Cited by 4 publications

References 13 publications

Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries

Key Parameters Governing the Reversibility of Si/Carbon/CMC Electrodes for Li-Ion Batteries

Thermally Induced Reactions between Lithiated Nano-Silicon Electrode and Electrolyte for Lithium-Ion Batteries

Establishing a Resilient Conductive Binding Network for Si-Based Anodes via Molecular Engineering

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