Electrochemical Attack Research Articles

Failure analysis of a C-type bourdon tube

This paper presents the failure analysis of a C-type Bourdon tube made of AISI 316L stainless steel, which was part of a pressure gauge. For the study, chemical composition and microstructure of the Bourdon tube were determined. Additionally, electrochemical attack with oxalic acid was used to asses if the microstructure was suspected of sensitization in samples taken near to and away from the failure. Finally, fractographic analysis of the failed Bourdon tube was accomplished by scanning electron microscopy. The results showed that the failure was due to an intergranular corrosion phenomenon that embrittled the material in the area close to the welding between the Bourdon tube and the joint.

Microstructural characterization and electrochemical behaviour of HVOF sprayed WC-Co-Cr coatings on 316L boiler steel stainless steel

Corrosion is the gradual erosion of metal, primarily because of electrochemical attacks especially under gaseous and alkaline conditions owing to the presence of sulphur and Alkali metals may cause rapid material degradation called Hot corrosion and result in untimely failure of components. To improve surface qualities for corrosion applications, the austenitic 316L stainless steel (SS) in this study was coated with Wc-10%Co–4%Cr utilizing the High-velocity oxy-fuel (HVOF) spray method. After the coated sample was heated to 800 °C for an hour, XRD was used to confirm the coating powder's composition. Using the FESEM technique, the microstructure features were examined, and XRD analysis was performed to ascertain the phase and composition of the substrate. Investigations were also conducted on the electrochemical corrosion characteristics that were impacted by the heat treatment after coating. SEM and EDAX technologies were used to characterize the sample and study its microstructure.

Reinventing concrete: Sustainable nano-alumina from metallic waste-cans and nano-ferrite for next-generation green magnetite heavyweight concrete

For the first time, sustainable nano-alumina, obtained from metallic waste-cans, is employed in green heavyweight magnetite concrete (GHMC). The GHMC mixes comprised fixed contents of 500, 125, 60, and 27.4 kg/m3 of cement, granulated blast furnace slag (GBFS), silica fume, and superplasticizer (SP), respectively. The benefits of typical magnetite heavyweight concrete was exploited alongside various percentages of research variables in different 11 mixes. The Sand (S) was used as a replacement for fine magnetite (FM) by (25 %, 50 %, 75 %), steel reinforced fiber (SRF) was added by (1 %, 1.5 %). Moreover, the nanoparticles included nano-Alumina (NA) by (2 %, 3 %, 4 %), nano-ferrite powder (NF) by 2 %, and 2 % NA+2 % NF. The effects of sand, SRF, NA, and NF were studied on slump, wet, dry, and oven dry densities, compressive strength (fc) and tensile strengths (ft), water absorption% (Wa%), electrochemical attack with chloride and sulfate, and thermogravimetric analysis (TGA), microstructure (SEM), and gamma-ray attenuation coefficient (LAC-μ, HVL, v) as shown in F ig. 1. The results revealed that adding 25 % sand, 1.5 % SRF, and 2 % NA+2 % NF boosted all of GHMC's tested properties. Although the replacement of 25 % sand slightly reduced the density of GHMC, it improved GHMC's workability, mechanical properties, and durability. Adding 1.5 % SRF resulted in an enhanced density as well as it improved all mechanical properties and durability. The fc, ft, and WA%, were enhanced by 31 %, 70 %, and 38 % at 28 days of age. The mixes incorporating 2%NA were better than those incorporating 2%NF for all testing properties. More improvements were noticed due to adding NA up to 4 %. Moreover, the mix incorporating 2 % NA+2 % NF had the best results compared to other nanoparticles percentages. For example, the dry density, fc and ft, and Wa% were improved up to 3.5 %, 66 %, 216 %, and 68 % at 28 days of age. Furthermore, the residual fc due to the exposure to chloride and sulfate was improved by 87 % and 78 % after 28 days, respectively. The TGA% at 1000 °C improved to 98.73 %, and LAC-μ improved by 83–102.4 %.

Investigation of electrolyte intermittent commutation effects on electrochemical machining

ABSTRACT Traditional blade electrochemical machining (ECM) adopts electrolyte unidirectional flow (EUF), resulting in serious accumulation of insoluble byproducts, gas, and Joule heat along the flow path. Here, an electrolyte intermittent commutation flow (EICF) was reported. Blade formed with EICF model was simulated, by comparison with EUF. Exploratory experiments were carried out, and how the time ratio of forward electrolyte flow time (t F) and reverse electrolyte flow time (t R) affects the blade ECM performance was investigated. The manufacturing accuracy and surface roughness depend on t F:t R, and they first improve and then deteriorate, reaching its optimal value at t F:t R = 1:3. Finally, the surface morphology is less affected by the t F:t R, the dissolution morphology exhibits that grain boundary is preferentially susceptible to electrochemical attack, compared with grain. The reason for this corrosion mechanism is that Ti and Nb are more easily enriched at the grain boundaries, while Cr, Fe and Ni are depleted.

Liquid Metal Electrodynamic Accumulation Microfluidics System for DNA Memory and Liquid Biopsy

AbstractThis study presents a liquid metal electrodynamic accumulation microfluidic (LEAM) device that effectively controls DNA dynamics using liquid metal (LM) electrodes and an applied electric field. The characteristics of LM in LEAM include electrochemical attack, and LM properties and behavior at high voltages. The findings demonstrate the ability of the LEAM system to control DNA dynamics and thermodynamics. Short‐sequence single stranded DNA (ssDNA) hybridization and displacement are performed using an exchange buffer solution. By scaling up the LEAM system for a droplet‐based approach, discrete manipulation of DNA samples is achieved. A three‐bit molecular ssDNA memory system using a molecular beacon system is demonstrated, and its application is extended as a diagnostic tool for detecting gene molecules such as micro‐RNA. This study highlights the potential of the LEAM system for use in various biomedical and biotechnological applications, owing to its effective handling of biomolecules.

Obtaining Porous Structures in the Form of Parallel Plates on Aluminum Substrates

We report how to obtain self-organized porous microstructures of Anodized Aluminum, using high purity Aluminum substrates of 1 cm2 and 0.5 mm, 0.13 mm thick. Microstructures were obtained by electrochemical attack, using a solution of NaOH and H2C2O4 at a temperature of 55 °C, 20V and attack times of 10, 20, 30, 60, 120, 180, 240 minutes. As a result, micrographs showed pores in the form of parallel sheets of aluminum oxides and hydroxides said according to the characterization tests

Improving Mechanical and Corrosion Behavior of 5052 Aluminum Alloy Processed by Cyclic Extrusion Compression

Background The severe plastic deformation approach and its well-known cyclic extrusion compression (CEC) method have been established as a powerful tool for fabricating bulk ultrafine-grained metals and alloys with improved properties. Objective This study focused on the microstructure evolution, hardness behavior, and corrosion properties of the CEC-processed Al5052 up to four passes compared to the initial annealed state. Methods The initial and CEC-processed Al5052 samples at different pass numbers were examined experimentally by EBSD analyses, hardness measurements, and corrosion resistance. Results Substantial grain refinement was attained from ~23 μm for the annealed sample to ~0.8 μm in the four passes sample. In addition, the hardness values considerably increased up to 75.7% after four passes from the initial value of 80 HV. In addition, the increment of pass numbers led to a more uniform dispersion of hardness values. Furthermore, the production of more stable protective oxide layers on the UFG structure of the CEC-processed sample led to the improvement in electrochemical response with a corrosion rate reduction from 1.49 to 1.02 mpy, respectively, in the annealed and final pass CEC-processed samples. In fact, the annealed sample manifested more large-sized and deeper pits than the CECed samples due to the increment of potential values and electrochemical attack of chlorine ions that finally deteriorates the corrosion performance. Conclusions CEC is an efficient method to improve the mechanical properties of materials due to substantial microstructural changes along with enhancement of electrochemical behavior because of the presence of small-sized and shallow pits.

Susceptibility to tribocorrosion degradation of 304 L stainless steel from dental structures in biological solution

In the case of metallic orthodontic brackets-archwires, the interactions between corrosion and wear are related to the conditions existing during the orthodontic therapy. The archwires are subjected simultaneously to an electrochemical attack by the oral environment and a mechanical sliding along with the brackets, which may destroy their protective surface film. To highlight the susceptibility to tribocorrosive behavior of AISI 304 L stainless steel, used in orthodontics, the tribocorrosion in sliding contact is performed in biological solution monitoring in-situ electrochemical and mechanical parameters. Friction corrosion or tribocorrosion affects the degradation process as well as the re-passivation of the tested material.

Hot corrosion behavior of an arc sprayed Fe-based amorphous coating in a simulated biomass firing environment

Coating technologies are cost-effective solutions to the Cl-induced hot corrosion problems in biomass boilers. In this study, an arc sprayed Fe-Cr-Mo amorphous coating was fabricated and exposed to a stimulated biomass firing condition at 500 °C and 600 °C. Fe and Cr in the coating were vulnerable to chlorination and continuously evaporated, leaving Cr depletion zones. The distribution of Mo was inhomogeneous, and Mo-rich zones were resistant to gaseous corrosive species but susceptible to electrochemical attack as temperature increased. The crevices in the coating were detrimental to its corrosion resistance by acting as corrodent diffusing channels.

A peridynamic model for galvanic corrosion and fracture

A coupled peridynamic (PD) corrosion-fracture model is introduced, in which the local corrosion rate is determined by solving the corresponding electrostatic problem. By being able to consider variable distributions of corrosion rates along the anodic surface, the model is particularly useful for simulating galvanic corrosion. A novel analytical calibration for parameters in the corrosion model is provided. The corrosion model is verified in terms of the electric potential, current density, and corrosion depth, and validated against experimental results for AE44 (Mg alloy) – mild steel and AE44 – AA6063 (Al alloy) galvanic couples taken from the literature. The PD results are also compared with those from a COMSOL FEM-based model. It is found that an artificial initial “step-down” in geometry at the galvanic joint is required for the COMSOL model in order to provide reasonable results, but it is not needed in the PD model. A coupled galvanic corrosion-fracture problem accounting for the combined electro-chemical attack and strains induced by mechanical loadings is solved.

Effects of Titanium Corrosion Products on In Vivo Biological Response: A Basis for the Understanding of Osseointegration Failures Mechanisms

Corrosion resistance is a key feature of titanium biocompatibility. However, Ti surfaces exposed to critical environments (such as, chronic infection and inflammation) can undergo corrosion processes in vivo, leading to an unfavorable biological response and clinical failure, which remains poorly explored. In this study, we characterized an experimental model to replicate the surface features of Ti corrosion process observed within in vivo failures, and the cellular, tissue and molecular events associated with corroded Ti surface implantation into subcutaneous and bone tissue of C57Bl/6 mice. Prior to in vivo implantation, commercially pure Ti Commercially pure titanium and Ti–6Al–4V alloy (Ti64) specimens were exposed to electrochemical polarization in 30% citric acid, while being polarized at 9 V against a saturated calomel electrode for 20 min. The electrochemical attack induced accelerated corrosion on both Ti-based specimens, producing structural and chemical changes on the surface, comparable to changes observed in failed implants. Then, microscopy and molecular parameters for healing and inflammation were investigated following control and corroded Ti implantation in subcutaneous (cpTi disks) and oral osseointegration (Ti64 screws) models at 3, 7, 14 and 21 days. The host response was comparatively evaluated between control and corroded Ti groups by microCT (bone), histology (H&E, histomorphometry, immunostaining and picrosirius red), and real-time PCR array for inflammatory and healings markers. Corroded cpTi disks and Ti64 screws induced a strong foreign body response (FBR) from 3 to 21 days-post implantation, with unremitting chronic inflammatory reaction lasting up to 21 days in both subcutaneous and osseointegration models. In the subcutaneous model, FBR was accompanied by increased amount of blood vessels and their molecular markers, as well as increased TRAP+ foreign body giant cell count. In the osseointegration model, failures were identified by an osteolytic reaction/bone loss detected by microCT and histological analyses. The corroded devices were associated with a dominant M1-type response, while controls showed transient inflammation, an M2-type response, and suitable healing and osseointegration. In conclusion, corrosion of Ti-based biomaterials induced exacerbated inflammatory response in both connective tissue and bone, linked to the upregulation of fibrosis, pro-inflammatory and osteoclastic markers and resulted in unfavorable healing and osseointegration outcomes.

Effect of Plasma Oxidation Treatment on Production of a SiOx/SiOxCyHz Bilayer to Protect Carbon Steel Against Corrosion

Because of its excellent properties, carbon steel is a material widely used in several sectors. However, it is easily corroded when exposed to the environment. Seeking to remedy this problem, the possibility of coating carbon steel with SiOx/SiOxCyHz films generated by deposition and oxidation in low-pressure plasmas was investigated. Specifically, the effects of excitation power of the oxidation plasma on layer thickness, chemical structure, elemental composition, and barrier properties of the obtained coatings were investigated. The coating of the steel with the SiOxCyHz film, generated by plasma in an atmosphere of hexamethyldisiloxane (HMDSO), increased the total resistance to the passage of electric current, measured by electrochemical impedance spectroscopy. However, under the condition of moderate power oxidation (50 W), the results point to the creation of a bilayer system with high resistance to electrochemical attack compared to the SiOxCyHz film, even though its thickness is less than this.

Examination of Reinforcement Steel Bars Exposed to the Atmosphere

Reinforcement steel bars are often exposed to the atmosphere before use in concrete structures. This exposure results in corrosion of these reinforcement bars. Corrosion of reinforcement bars is a common form of degradation of reinforced concrete structures. The electrochemical attack affects the mechanical properties of steel rebars. This study analysed the effect of exposing reinforcing steel bars to the atmosphere. The bars were divided into two; one part was exposed to the atmosphere for a period of four months during the rainy season while the other was unexposed. Afterwards; some mechanical, corrosion and metallographic tests were carried out on the steel samples. The results obtained showed that the hardness, impact strength and ductility increased with exposure while the yield and tensile strengths decreased with exposure. The exposed bar had high corrosion rates than the unexposed bar in 1M hydrochloric acid (HCl) while in 1M sodium chloride (NaCl), the corrosion rates for both the exposed and unexposed bars did not follow a particular trend

Examination of Reinforcement Steel Bars Exposed to the Atmosphere

Reinforcement steel bars are often exposed to the atmosphere before use in concrete structures. This exposure results in corrosion of these reinforcement bars. Corrosion of reinforcement bars is a common form of degradation of reinforced concrete structures. The electrochemical attack affects the mechanical properties of steel rebars. This study analysed the effect of exposing reinforcing steel bars to the atmosphere. The bars were divided into two; one part was exposed to the atmosphere for a period of four months during the rainy season while the other was unexposed. Afterwards; some mechanical, corrosion and metallographic tests were carried out on the steel samples. The results obtained showed that the hardness, impact strength and ductility increased with exposure while the yield and tensile strengths decreased with exposure. The exposed bar had high corrosion rates than the unexposed bar in 1M hydrochloric acid (HCl) while in 1M sodium chloride (NaCl), the corrosion rates for both the exposed and unexposed bars did not follow a particular trend.

Optical biosensor for biogenic amines detection used a porous silicon matrix

The content of biogenic amines has been studied due to the toxicity of these compounds in humans when are consumed exogenously, and is used as an indicator of quality in the food industry. The manly method for its determination is high performance liquid chromatography. However, it requires a long time for analysis. An alternative method is the use of biosensors, porous silicon with gold nanoparticles were obtained by electrochemical attack assisted with metal salt. These substrates were used for the construction of a biosensor capable of detecting BA using diamine oxidase enzyme as an element of biological recognition and is binding using the self-assembled monolayers method. The correlation between scanning electron microscopy, X-ray dispersive energy spectroscopy, and Fourier Transform infrared spectroscopy analysis, demonstrated the correct construction of the biosensor and the detection of biogenic amines by interaction with the enzyme. Finally, with the built biosensor it was possible to detect three important biogenic amines found in food.

Facile and Ultraclean Graphene-on-Glass Nanopores by Controlled Electrochemical Etching.

A wide range of approaches have been explored to meet the challenges of graphene nanostructure fabrication, all requiring complex and high-end nanofabrication platform and suffering from surface contaminations, potentially giving electrical noise and increasing the thickness of the atomically thin graphene membrane. Here, with the use of an electrical pulse on a low-capacitance graphene-on-glass (GOG) membrane, we fabricated clean graphene nanopores on commercially available glass substrates with exceptionally low electrical noise. In situ liquid AFM studies and electrochemical measurements revealed that both graphene nanopore nucleation and growth stem from the electrochemical attack on carbon atoms at defect sites, ensuring the creation of a graphene nanopore. Strikingly, compared to conventional TEM drilled graphene nanopores on SiN supporting membranes, GOG nanopores featured an order-of-magnitude reduced broadband noise, which we ascribed to the electrochemical refreshing of graphene nanopore on mechanically stable glass chips with negligible parasitic capacitance (∼1 pF). Further experiments on double-stranded DNA translocations demonstrated a greatly reduced current noise, and also confirmed the activation of single nanopores. Therefore, the exceptionally low noise and ease of fabrication will facilitate the understanding of the fundamental property and the application of such atomically thin nanopore sensors.

Assessment of fatigue life of a pre-corroded aircraft wing under drag alternating load

The application of high strength aluminum alloys in aircraft structures is significant for the aeronautics industry. During life service, the aircraft wings undergo fatigue and the attack from corrosive chemicals of the surrounded atmosphere. The present research work studied the effect of pitting corrosion on fatigue life of the Onera M6 wing. An aluminum alloy 2024-T3 scale model (prototype) of the Onera M6 wing was built. The similarity analysis helped to calculate the dimensions of the prototype. A computational fluid dynamics (CFD) model was employed to estimate the drag coefficient in flight conditions and the airfoil’s center of pressure. The aircraft wing was corroded electrochemically in a 3.5% wt. NaCl solution at three different times 11, 33 and 66 h named low, medium and high corrosion, respectively. Then, a fatigue test was carried out on the aircraft wing subjected to an alternating drag cyclic loading. The real-time strain of the aircraft wing was measured through strain gauges and an oscilloscope during the fatigue test. The normal stress in the aircraft wing was calculated from the strain data measured experimentally. A curve of the number of loading cycles versus normal stress was built during the fatigue test for each corrosion condition. Then, a nonlinear curve-fitting was applied to the curve of number of loading cycles vs normal stress to estimate the fatigue life of aircraft wing in flight conditions. The results indicated that the fatigue life of the aircraft wing decreased up to 72% for the most severe corrosion condition. The aluminum alloy 2024-T3 presented a high corrosion rate during the electrochemical attack due to the rupture of its protective oxide layer. The most affected area by pitting corrosion was found in the extrados wall associated with higher curvature. The aircraft wing did not present cracking nor an increase in the size of the pitting corrosion by the effect of the stress concentration in fatigue testing.

Electrochemical attack and corrosion of platinum electrodes in dielectrophoretic diagnostic devices.

Though the advances in microelectronic device fabrication have realized new capabilities in integrated analytical and diagnostic platforms, there are still notable limitations in point-of-care sample preparation. AC electrokinetic devices, especially those leveraging dielectrophoresis (DEP), have shown potential to solve these limitations and allow for sample-to-answer in a single point-of-care device. However, when working directly with whole blood or other high conductance (~ 1S/m) biological fluids, the aggressive electrochemical conditions created by the electrode can fundamentally limit the device operation. In this study, platinum wire-based electrode devices spanning circular polytetrafluorethylene (PTFE) wells and a planar microarray device with sputtered platinum electrodes were tested in plasma and PBS buffers of differing concentration across a wide range of frequencies and electric field intensities (AC voltages) to determine their respective safe regions of operation and to gain an understanding about the failure mechanisms of this class of device. At frequencies of 10kHz and below, the upper bound of operation is the degradation of electrodes due to electrochemical attack by chlorine overcoming the native platinum oxide passivation. At higher frequencies, 100kHz and above, the dielectric loss and subsequent heating of the buffer will boil before the electrodes suffer observable damage, due to the slow irreversible reaction kinetics. Effective dielectrophoretic capture of small biological particles at these frequencies is limited, and heat/oxidative denaturation of target material are a major concern. A new class of smaller devices, ones capable of high throughput at voltages low enough to maintain the integrity of the platinum passivation layer, is needed to mitigate these fundamental limitations.

Accelerated aging of anticorrosive coatings: Two-stage approach to the AC/DC/AC electrochemical method

Organic coatings are nowadays the most common and cost-effective approach to extend the service life of metallic structures subjected to weathering conditions. The development of new and more effective protective coatings is closely related to the rapid assessment of the anticorrosive performance before industrialization. Currently, the coating/metallic substrate system evaluation is made using accelerated standardized test methods. However, the time needed to perform such tests can be long, and in some cases can hold up for thousands of hours. The AC/DC/AC method is an accelerated cyclic test, consisting of a combination of electrochemical impedance spectroscopy (EIS/AC) characterization and cathodic polarisations (DC). The latter technique has been widely used to assess the adhesion of coatings to the metallic substrate but, to the best knowledge of the authors, no clear evidences have been provided that the aging promoted by AC/DC/AC is comparable to the one promoted by standardized accelerated aging tests, such as the neutral salt spray test. Said comparison is necessary to be able to support the use of the AC/DC/AC method to assess the anticorrosive performance of coatings. This work addresses this gap and goes further, proposing an innovative two-stage AC/DC/AC procedure that allows a better control of the physical delamination inherent to this technique, while promoting a chemical and electrochemical attack of coating and metallic substrate. Two water-based organic primers applied on cold rolled steel were aged by neutral salt spray (aging characterized by EIS) and by the proposed AC/DC/AC procedure. The obtained results were critically compared based on the EIS analysis. It was observed that the two-stage AC/DC/AC procedure mimicked the degradation mechanisms occurring during the neutral salt spray test, but producing results in less than 25% of the aging time.

Porous Germanium Anode for Li-Ion Batteries

Due to the steady growing demand for higher performance electronic devices it is required an increase of the actual specific energy of Lithium Ion Batteries (LIBs)[1]. This can be achieved enhancing the gravimetric capacity of the electrodes, i.e. the amount of charge that can be stored per unit of mass of the active material. Currently a variety of cathode materials are available, being lithium metal oxides the most commonly used, while for the anode the choice is essentially between TiO2 or carbonaceous materials, among which Graphite is by far the most employed. The theoretical gravimetric capacity of Graphite is 372 mAh/g but several materials show higher capacities. In this respect, the highest gravimetric capacities are found in Lithium metal (3862 mAh/g), Silicon (4200 mAh/g) and Germanium (1624 mAh/g). Even though these numbers would suggest Lithium metal as the best possible active material, it has been discarded due to its high reactivity inducing dendrites formation upon charge and discharge processes, which could eventually lead to short circuits. Silicon and Germanium also show improved capacities compared to Graphite but they both suffer huge volume changes (up to 400%) upon cycling, which could lead to the pulverization of the electrodes. Nano-structuring these materials is an approach to overcome this issue, realizing structures which can reversibly accommodate the occurring volume variations. It is easier to obtain a Germanium compliant matrix rather than a Silicon one, as Germanium requires an average pore dimension that is bigger compared to Silicon[2]. Furthermore, Germanium shows a higher electrical conductivity (10,000 times higher than Silicon) and lithium ion diffusion rate (400 times higher than Silicon), which could make it suitable for high performance applications. These are the reasons that led us to test Germanium as an alternative anodic material with respect to Graphite. In this work we present the results of our novel anodic material made of porous Germanium. The Germanium films are directly grown on a metallic current collector through a plasma enhanced chemical vapor deposition technique (PECVD) without any binder, and subsequently nano-structured to realize a porous matrix using a hydrofluoric acid electrochemical attack. Molybdenum or Stainless Steel were used as current collectors without requiring any binder to enhance the adhesion of Germanium, i.e. the mass loading is truly and uniquely represented by active material. Moreover, the PECVD technique permits to obtain a higher purity compared to chemically grown materials via standard reactions in solution. These anodes are able to perform hundreds of charge and discharge cycles at very high C-rates, retaining a stable capacity of more than 950 mAh/g even at currents as high as 5C (considering 1C as 1600 mA/g), which is 2.5 times the theoretical Graphite capacity. 2032 coin-type half-cells were assembled coupling the electrode to pure Lithium metal used as counter and reference electrode. A standard electrolyte solution composed by EC:DMC has been used with different additives (vinylene carbonate-VC and fluoroethylene carbonate-FEC) whose effect on the performances will be shown. The active material layer thickness varied between 1 to 5 microns and the mass loadings ranged from 0.2 to 1.5 mg. Various etching recipes have been tested to obtain different porous morphologies. As an alternative technique to nano-structure the materials, a suitably tuned Ion Implantation technique has been exploited: the results will be shown for comparison, along with results from bulk samples in order to show the effectiveness of the nano-structuration process on the cell performance. The best results were obtained using porous Germanium grown onto Molybdenum substrate adding FEC: in graph 1 is reported the Capacity vs. Cycle Number plot for one of these samples, which has been tested for thousand cycles at high C-rates (mass loading 0.24 mg). [1] G. Zubi, R. Dufo-López, M. Carvalho e G. Pasaoglu, «The lithium-ion battery: State of the art and future perspectives,» Renewable and Sustainable Energy Reviews, vol. 89, pp. 292-308, 2018. [2] Z. Hu, S. Zhang, C. Zhang e G. Cui, «High performance germanium-based anode materials,» Coordination Chemistry Reviews, vol. 326, pp. 34-85, 2016. Figure 1