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The oxygen-evolving IrO2-Ta2O5/Ti anode (OEA), primarily used in electrolyzers for plating, metal powder production, electrowinning (EW), and water electrolysis, is analyzed. This study focuses on the distribution of oxygen evolution reaction (OER) activity and the associated operational loss over the randomized OEA texture. The OER activity and its distribution across the IrO2-Ta2O5 coating surface are key factors that influence EW operational challenges and the lifecycle of OEA in EW processes. To understand the OER activity distribution over the coating’s randomized texture, we performed analyses using anode polarization in acid solution at both low and high (EW operation relevant) overpotentials and electrochemical impedance spectroscopy (EIS) during the OER. These measurements were conducted on anodes in both their as-prepared and deactivated states. The as-prepared anode was deactivated using an accelerated stability test in an acid solution, the EW simulating electrolyte. The obtained data are correlated with fundamental electrochemical properties of OEA, such as structure-related pseudocapacitive responses at open circuit potential in the same operating environment. OER and Ir dissolution kinetics, along with the physicochemical anode state upon deactivation, are clearly characterized based on current and potential dependent charge transfer resistances and associated double layer capacitances obtained by EIS. This approach presents a useful tool for elucidating, and consequently tailoring and predicting, anode OER activity and electrolytic operational stability in industrial electrochemical applications.

The ability to repair damage spontaneously, which is termed self-healing, is an important survival feature in nature because it increases the lifetime of most living creatures. This feature is highly desirable for rechargeable batteries because the lifetime of high-capacity electrodes, such as silicon anodes, is shortened by mechanical fractures generated during the cycling process. Here, inspired by nature, we apply self-healing chemistry to silicon microparticle (SiMP) anodes to overcome their short cycle-life. We show that anodes made from low-cost SiMPs (~3–8 µm), for which stable deep galvanostatic cycling was previously impossible, can now have an excellent cycle life when coated with a self-healing polymer. We attain a cycle life ten times longer than state-of-art anodes made from SiMPs and still retain a high capacity (up to ~3,000 mA h g −1 ). Cracks and damage in the coating during cycling can be healed spontaneously by the randomly branched hydrogen-bonding polymer used. The ability to self-heal is an important survival feature in nature, with in-built systems working to correct faults and extend the lifetimes of organisms. Now, self-healing chemistry has been applied to overcome the short cycling lifetime of high-capacity rechargeable lithium-ion batteries with silicon-microparticle anodes that suffer from mechanical fractures.

We report the creation of a nanoscale electrochemical device inside a transmission electron microscope--consisting of a single tin dioxide (SnO₂) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO₂) cathode--and the in situ observation of the lithiation of the SnO₂ nanowire during electrochemical charging. Upon charging, a reaction front propagated progressively along the nanowire, causing the nanowire to swell, elongate, and spiral. The reaction front is a \"Medusa zone\" containing a high density of mobile dislocations, which are continuously nucleated and absorbed at the moving front. This dislocation cloud indicates large in-plane misfit stresses and is a structural precursor to electrochemically driven solid-state amorphization. Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, our observations provide important mechanistic insight for the design of advanced batteries.

Electrooxidation has proven to be an efficient technique for treating effluents containing ammoniacal nitrogen and organic matter. In the present study, electrooxidation trials were conducted with an ammoniacal effluent generated at a fertilizer depot, containing 0.24 mol L −1 of N-NH 3 and 0.90 mol L −1 of Cl − . The Ti/RuO 2 electrodes were used in a stirred batch electrochemical reactor. The results obtained, employing a current density of 60 mA cm −2 , showed degradation rates of 99.9% for ammoniacal nitrogen and 75.6% for organic matter. Accelerated anode degradation tests with the same solution, maintaining a constant current density of 1,000 mA cm −2 , indicated that after 300 h, a partial dissolution of the RuO 2 coating was observed, along with the formation of a passive TiO 2 film and an increase of approximately 24% of the initial anodic potential value. Considering a working current density of 60 mA cm −2 , the estimated service life of the Ti/RuO 2 anode is 6 years.

As a promising energy storage system, sodium-ion batteries face challenges related to the stability and high-rate capability of their electrode materials, especially carbon, which is the most studied anode. Previous studies have demonstrated that three-dimensional architectures composed of porous carbon materials with high electrical conductivity have the potential to enhance the storage performance of sodium-ion batteries. Here, high-level N/O heteroatoms-doped carbonaceous flowers with hierarchical pore architecture are synthesized through the direct pyrolysis of homemade bipyridine-coordinated polymers. The carbonaceous flowers could provide effective transport pathways for electrons/ions, thus allowing for extraordinary storage properties in sodium-ion batteries. As a consequence, sodium-ion battery anodes made of carbonaceous flowers exhibit outstanding electrochemical features, such as high reversible capacity (329 mAh g−1 at 30 mA g−1), superior rate capability (94 mAh g−1 at 5000 mA g−1), and ultralong cycle lifetimes (capacity retention rate of 89.4% after 1300 cycles at 200 mA g−1). To better investigate the sodium insertion/extraction-related electrochemical processes, the cycled anodes are experimentally analyzed with scanning electron microscopy and transmission electron microscopy. The feasibility of the carbonaceous flowers as anode materials was further investigated using a commercial Na3V2(PO4)3 cathode for sodium-ion full batteries. All these findings indicate that carbonaceous flowers may possess great potential as advanced materials for next-generation energy storage applications.

The development of lithium-ion batteries largely relies on the cathode and anode materials. In particular, the optimization of cathode materials plays an extremely important role in improving the performance of lithium-ion batteries, such as specific capacity or cycling stability. Carbon coating modifying the surface of cathode materials is regarded as an effective strategy that meets the demand of Lithium-ion battery cathodes. This work mainly reviews the modification mechanism and method of carbon coating, and summarizes the recent progress of carbon coating on some typical cathode materials (LiFePO4, LiMn2O4, LiCoO2, NCA (LiNiCoAlO2) and NCM (LiNiMnCoO2)). In addition, the limitations of the carbon coating on the cathode are also introduced. Suggestions on improving the effectiveness of carbon coating for future study are also presented.

Although various silicon carbide (SiC) power devices with very high blocking voltages over 10 kV have been demonstrated, basic issues associated with the device operation are still not well understood. In this paper, the promise and limitations of high-voltage SiC bipolar devices are presented, taking account of the injection-level dependence of carrier lifetimes. It is shown that the major limitation of SiC bipolar devices originates from band-to-band recombination, which becomes significant at a high-injection level. A trial of unipolar/bipolar hybrid operation to reduce power loss is introduced, and an 11 kV SiC hybrid (merged pin-Schottky) diodes is experimentally demonstrated. The fabricated diodes with an epitaxial anode exhibit much better forward characteristics than diodes with an implanted anode. The temperature dependence of forward characteristics is discussed.

The current work addresses a mass/cost-optimization procedure for galvanic anode cathodic protection systems based on both cathodic protection (CP) standards and numerical simulation. An approach is developed for optimizing the number and dimensions of the galvanic anodes, distributing the optimized anodes on the support structure, and finally evaluating the protective potential on the structure during the lifetime by using finite element (FE) software. An algorithm based on sequential quadratic programming is used for optimizing the number and dimensions of the anodes. Both simplified and detailed models are suggested for calculating the protective potential on the structure. The simplified model is selected based on its advantages in terms of calculation time and compatibility with DNV standard data. A time-dependent FE model is used to take into account the electrical isolation degradation of the structure coating as well as the mass reduction of the anodes during the CP lifetime. The performance of the proposed optimization process is examined on a mono bucket inspired (with some simplifications) by the Dogger Bank metrological mast in England. The optimized designs for different coating and anode types are compared and the best designs in terms of both cost and protective potential during the lifetime are suggested. The achieved results show that the proposed optimization procedure can reduce the cost of the CP system around 70% compared to the original non-optimized CP design of the Dogger Bank metrological mast. Furthermore, evaluating the time-evolution performance of the CP systems can reduce their lifetime uncertainty.

Accelerated cyclic aging tests are very important for research and industry to quickly characterize lithium-ion cells. However, the accentuation of stress factors and the elimination of rest periods lead to an apparent capacity fade, that can be subsequently recovered during a resting phase. This effect is attributed to the inhomogeneous lithium distribution in the anode and is observable with differential voltage analysis (DVA). We tested cylindrical 18,650 cells with Li(NixCoyAlz)O2-graphite/silicon chemistry during two cycling and resting phases. The capacity, the pulse resistance, the DVA, and the capacity difference analysis are evaluated for cells cycled at different average SOC and current rates. An apparent capacity loss of up to 12% was reported after 200 FCE for cells cycled under the presence of pressure gradients, while only 1% were at low-pressure gradients. The subsequent recovery was up to 80% of the apparent capacity loss in some cases. The impact of silicon cannot be estimated as it shows no features in the dV/dQ curves. We observe a recovery of apparent resistance increase, which is not reported for cells with pure graphite anodes. Finally, we demonstrate the strong impact of apparent aging for the lifetime prediction based on standard accelerated cyclic aging tests.

The accumulation of solid electrolyte interphases (SEI) in graphite anodes related to elevated formation rates (0.1C, 1C and 2C), cycling rates (1C and 2C), and electrode-separator lamination is investigated. As shown previously, the lamination technique is beneficial for the capacity aging in graphite-LiNi1/3Mn1/3Co1/3O2 cells. Here, surface resistance growth phenomena are quantified using electrochemical impedance spectroscopy (EIS). The graphite anodes were extracted from the graphite NMC cells in their fully discharged state and irreversible accumulations of lithium in the SEI are revealed using neutron depth profiling (NDP). In this post-mortem study, NDP reveals uniform lithium accumulations as a function of depth with lithium situated at the surface of the graphite particles thus forming the SEI. The SEI was found to grow logarithmically with cycle number starting with the main formation in the initial cycles. Furthermore, the EIS measurements indicate that benefits from lamination arise from surface resistance growth phenomena aside from SEI growth in superior anode fractions.