High-energy ball milling is used to recycle Si wafers to produce Si powders for negative electrodes of Li-ion batteries. The resulting Si powder consists in micrometric Si agglomerates made of ...cold-welded submicrometric nanocrystalline Si particles. Silicon-based composite electrodes prepared with ball-milled Si wafer can achieve more than 900 cycles with a capacity of 1200 mAh g−1 of Si (880 mAh g−1 of electrode) and a coulombic efficiency higher than 99%. This excellent electrochemical performance lies in the use of nanostructured Si produced by ball milling, the electrode formulation in a pH 3 buffer solution with CMC as binder and the use of FEC/VC additives in the electrolyte. This work opens the way to an economically attractive recycling of Si wastes.
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•This work provides a cheap and green way to produce Si anodes for Li-ion batteries.•Ball-milled Si wafer is used as active material.•900 cycles at 1200 mAh g−1 of Si are achieved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A simple and versatile preparation of Zn(II)–poly(carboxylates) reticulated binders by the addition of Zn(II) precursors (ZnSO4, ZnO, or Zn(NO3)2) into a preoptimized poly(carboxylic acids) ...binder solution is proposed. These binders lead systematically to a significantly improved electrochemical performance when used for the formulation of silicon-based negative electrodes. The formation of carboxylate-Zn(II) coordination bonds formation is investigated by rheology and FTIR and NMR spectroscopies. Mechanical characterizations reveal that the coordinated binder offers a better electrode coating cohesion and adhesion to the current collector, as well as higher hardness and elastic modulus, which are even preserved in the presence of a carbonate solvent (i.e., in battery operation conditions). Ultimately, as shown from operando dilatometry experiments, the electrode expansion during lithiation is reduced, mitigating electrode mechanical failure. Such coordinatively reticulated electrodes outperform their uncoordinated counterparts with an improved capacity retention of over 30% after 60 cycles.
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We report a facile and scalable process to prepare nanostructured 3D porous networks combining graphene, N-doped carbon and silicon nanoparticles (G@Si@C) as a promising anode material for batteries. ...It consists of preparing polymethylmethacrylate particles decorated by Si/graphene oxide and polypyrrole (PPy) in a one-pot process, followed by an appropriate thermal treatment that decomposes PMMA and converts graphene oxide into graphene and polypyrrole into N-doped carbon. The so-formed electrically conducting 3D porous network containing Si nanoparticles inside the cell walls accommodates the large volume changes of Si during charging/discharging and provides a fast electrolyte penetration/diffusion. Therefore, the designed G@Si@C material presents an excellent reversible capacity of 740 mA h g −1 at a current density of 0.14 A g −1 based on the total mass loading of the composite, with more than 99% coulombic efficiency, high rate capability and good cyclability, suggesting great potential for application as an anode material for lithium-ion batteries.
We report a facile and scalable process to prepare nanostructured 3D porous networks combining graphene, N-doped carbon and silicon nanoparticles (G@Si@C) as a promising anode material for batteries. ...It consists of preparing polymethylmethacrylate particles decorated by Si/graphene oxide and polypyrrole (PPy) in a one-pot process, followed by an appropriate thermal treatment that decomposes PMMA and converts graphene oxide into graphene and polypyrrole into N-doped carbon. The so-formed electrically conducting 3D porous network containing Si nanoparticles inside the cell walls accommodates the large volume changes of Si during charging/discharging and provides a fast electrolyte penetration/diffusion. Therefore, the designed G@Si@C material presents an excellent reversible capacity of 740 mA h g
−1
at a current density of 0.14 A g
−1
based on the total mass loading of the composite, with more than 99% coulombic efficiency, high rate capability and good cyclability, suggesting great potential for application as an anode material for lithium-ion batteries.
A facile and scalable process to prepare nanostructured 3D porous networks combining graphene, N-doped carbon and silicon nanoparticles (G@Si@C) as a promising anode material for lithium ion batteries.
A Si-based anode with improved performance can be achieved using high-energy ball-milling as a cheap and easy process to produce Si powders prepared from a coarse-grained material. Ball-milled ...powders present all the advantages of nanometric Si powders, but not the drawbacks. Milled powders are nanostructured with micrometric agglomerates (median size 10 m), made of submicrometric cold-welded particles with a crystallite size of 10 nm. The micrometric particle size provides handling and non-toxicity advantages compared to nanometric powders, as well as four times higher tap density. The nanostructuration is assumed to provide a shortened Li
+
diffusion path, a fast Li
+
diffusion path along grain boundaries and a smoother phase transition upon cycling. Compared to non-milled 15 m powders, the improved performance of nanostructured milled Si powders is linked to a strong lowering of particle disconnection at each charge, while the irreversibility due to SEI formation remains unchanged. An electrode prepared in acidic conditions with the CMC binder achieves 600 cycles at more than 1170 mA h per gram of the milled Si-based electrode, in an electrolyte containing FEC/VC SEI-forming additives, with a coulombic efficiency above 99%, compared to less than 100 cycles at the same capacity for an electrode containing nanometric Si powder.
A Si-based anode with improved performance can be achieved using high-energy ball-milling as a cheap and easy process to produce Si powders prepared from a coarse-grained material.
An Fe3O4/Cu nanostructured prototype electrode was developed from a 100% bottom‐up approach thanks to an original three‐step electrodeposition procedure that enlists 1) the growth of a ZnO ...nanocolumnar template, 2) the filling of the template voids by copper prior to the dissolution of the zincite nanopillars, and 3) the plating on the remaining copper nanodots of the Fe3O4 phase. The key technological point is that ZnO readily forms nanorod arrays by self‐assembly when an aqueous solution of ZnII, saturated by dioxygen, is cathodically polarized. The as‐obtained inorganic solid template is sufficiently stable for further deposition steps of any kind (metals, oxides, polymers, and so on) but is easy to remove in both acidic and alkaline media. The self‐supported Fe3O4/Cu nanostructured electrode shows, besides sustained capacity retention, outstanding rate capability when electrochemically tested versus Li. This original and soft process, derived from template‐assisted synthesis, avoids fixing (mechanically) a nanoporous membrane on the substrate, thus, enabling nanostructural design on shapeless surfaces.
Fe3O4/Cu nanostructured prototype electrodes can be developed either by using conventional, template‐assisted electrochemical synthesis via the electrodeposition of copper through an alumina membrane or, thanks to an original 100% bottom‐up process, by using the sacrificial electrodeposition of ZnO nanorods that act as a template.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Ion channels are transmembrane proteins that allow the passage of ions according to the direction of their electrochemical gradients. Mutations in more than 30 genes encoding ion channels have been ...associated with an increasingly wide range of inherited cardiac arrhythmias. In this line, ion channels become one of the most important molecular targets for several classes of drugs, including antiarrhythmics. Nevertheless, antiarrhythmic drugs are usually accompanied by some serious side effects. Thus, developing new approaches could offer added values to prevent and treat the episodes of arrhythmia. In this sense, green tea catechins seem to be a promising alternative because of the significant effect of Epigallocatechin-3-Gallate (E3G) on the electrocardiographic wave forms of guinea pig hearts. Thus, the aim of this study was to evaluate the benefits-risks balance of E3G consumption in the setting of ion channel mutations linked with aberrant cardiac excitability phenotypes. Two gain-of-function mutations, Nav1.5-p.R222Q and Nav1.5-p.I141V, which are linked with cardiac hyperexcitability phenotypes were studied. Computer simulations of action potentials (APs) show that 30 μM E3G reduces and suppresses AP abnormalities characteristics of these phenotypes. These results suggest that E3G may have a beneficial effect in the setting of cardiac sodium channelopathies displaying a hyperexcitability phenotype.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Local reduction of poly(tetrafluoroethylene) (PTFE) was achieved by scanning electrochemical microscopy (SECM). The PTFE reduction process was analyzed by the current transients, which helped propose ...general trends for PTFE microfabrication. The SECM was used to investigate quantitatively the kinetics of PTFE phase transformation. In a short time, a nucleation process accounts for the PTFE reduction evolution. The nucleation rate follows a potential dependency similar to that observed for conducting polymer growth or metal deposition. At long time, the expansion of the PTFE carbonization proceeds in a hemi-ellipsoidal fashion, the radial expansion being much easier than the in-depth one. Those expansions can be correlated to the tip current when changing reduction time, reducing species concentration, nature of the electrolytic solution, SECM tip radius, and tip−substrate separation. The stoichiometry of the reduction was estimated, and the existence of two kinetic regimes owing to the redox mediator reduction potential was evidenced, which confirmed previous results by feedback experiments. A rough model was proposed in which the reduction along the in-depth direction is mainly controlled by a diffusive process while the material resistivity controls the radial expansion. The observed variations may be explained by penetration of the reducing species into the rough reduced PTFE material.
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