Li-In alloy anode and Nb2CTX2 artificial solid-electrolyte interphase for practical Li metal batteries

Lithium metal (Li) have received growing attention for use in rechargeable electrochemical cells with various types of cathodes owing to their potential as high-capacity anodes. However, continuous electrochemical reactions and...

CO2 Reduction on Single-Atom Ir Catalysts with Chemical Functionalization

As promising catalytic systems, single-atom catalysts (SACs) demonstrate improved catalytic performance for electrochemical reactions. However, the pinning of metal atoms on surfaces usually depends on the adsorption on defects. In...

6 Bipolar Electrochemistry for Synthesis

Bipolar electrochemistry has gained remarkable interest in recent years, especially in the fields of materials science and organic electrosynthesis. This is due to the interesting features of this particular electrochemical technology, such as the contactless nature of the electrochemical reactions, the use of low concentrations of supporting electrolytes, and the synergetic action of electrophoresis and electrolysis. In this chapter, the most important contributions regarding bipolar electrochemistry for the electrosynthesis of novel functional materials are reviewed. These contributions include the most traditional industrial applications and bipolar reactors for electroorganic synthesis, as well as innovative approaches for the fabrication of anisotropic materials and gradient surfaces. The peculiar characteristics of bipolar electrochemistry in these fields are emphasized.

15 Paired Electrolysis

While paired electrochemical reactions have a history that can be traced back to the 19th century and have been very effectively used for the production of commercial products, the larger synthetic community has only recently started to embrace the opportunities this approach offers to maximize the overall energy and atom efficiency of electrochemical processes. In this review, a summary of these efforts is presented in the context of four classes of paired electrochemical reactions. These classes of reaction involve parallel processing of products at the anode and cathode, divergent reactions that use a single starting material in different ways, convergent reactions that combine products made at the anode and cathode, and sequential reactions that pass a substrate between the electrodes.

Analisis Termodinamika dan Kinetika Nanopartikel Karbon (C-Dot) dari Buah Durian Sebagai Inhibitor Korosi Tembaga

Corrosion is a physical interaction between the metal and its environment, which results in changes in the metal's properties due to chemical or electrochemical reactions. The corrosion rate can be reduced by adding a corrosion inhibitor. Uses of nanotechnology for corrosion prevention is one of the first technical because almost made structures rely on the stability of a 1–2 nm thick passive film which provides stability to the underlying material. Herein we report the thermodynamic and kinetic analysis of carbon-dots from Durian as inhibitor copper corrosion. To test the anticorrosive performance and analyze thermodynamic properties in its role as a corrosion inhibitor on copper using potentiodynamic polarization. The thermodynamic-kinetic parameters of corrosion obtained values of H‡ = 60.44 kJmol-1, ΔS‡ = -73.9 kJmol-1, and ΔG‡ = 82.83 kJmol-1, show that the attendance of C-dot as a corrosion inhibitor causes a non-spontaneous reaction rate to be proven by increasing spontaneity (ΔG‡). The value of activation energy samples was higher than the blank, indicates the presence of C-dot effective to reduce the rate of corrosion of the metal.

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

The wafer-scale integration of graphene is of great importance in view of its numerous applications proposed or underway. A good graphene–silicon interface requires the fine control of several parameters and may turn into a high-cost material, suitable for the most advanced applications. Procedures that can be of great use for a wide range of applications are already available, but others are to be found, in order to modulate the offer of different types of materials, at different levels of sophistication and use. We have been exploring different electrochemical approaches over the last 5 years, starting from graphene oxide and resulting in graphene deposited on silicon-oriented surfaces, with the aim of understanding the reactions leading to the re-establishment of the graphene network. Here, we report how a proper choice of both the chemical environment and electrochemical conditions can lead to a more controlled and tunable graphene–Si(111) interface. This can also lead to a deeper understanding of the electrochemical reactions involved in the evolution of graphene oxide to graphene under electrochemical reduction. Results from XPS, the most suitable tool to follow the presence and fate of functional groups at the graphene surface, are reported, together with electrochemical and Raman findings.

Electrolyte reactivity at the charged Ni-rich cathode interface and degradation in Li-ion batteries

The chemical and electrochemical reactions at the positive electrode-electrolyte interface in Li-ion batteries are hugely influential on cycle life and safety. Ni-rich layered transition metal oxides exhibit higher interfacial reactivity than their lower Ni-content analogues, reacting via poorly understood mechanisms. Here, we study the role of the electrolyte solvent, specifically cyclic ethylene carbonate (EC) and linear ethyl methyl carbonate (EMC), in determining the interfacial reactivity at LiNi0.33Mn0.33Co0.33O2 (NMC111) and LiNi0.8Mn0.1Co0.1O2 (NMC811). Parasitic currents are measured during high voltage holds in NMC/Li4Ti5O12 (LTO) cells, LTO avoiding parasitic currents related to anode-cathode reduction species cross-over, and are found to be higher for EC-containing vs. EC-free electrolytes with NMC811. No difference between electrolytes are observed with NMC111. On-line gas analysis reveals this to be related to lattice oxygen release, and accompanying electrolyte decomposition, which increases substantially with greater Ni content, and for EC-containing electrolytes with NMC811. This is corroborated by electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM) of NMC811 after the voltage hold, which show a higher interfacial impedance and a thicker oxygen-deficient rock-salt surface reconstruction layer, respectively. Combined findings from solution NMR, ICP (of electrolytes) and XPS analysis (of electrodes) reveal that higher lattice oxygen release from NMC811 in EC-containing electrolytes is coupled with more electrolyte breakdown and higher amounts of transition metal dissolution compared to EC-free electrolyte. Finally, new mechanistic insights for the chemical oxidation pathways of electrolyte solvents and, critically, the knock-on chemical and electrochemical reactions that further degrade the electrolyte and electrodes curtailing battery lifetime are provided.

Self-Optimization of Continuous Flow Electrochemical Synthesis Using Fourier Transform Infrared and Gas Chromatography

A continuous-flow electrochemical synthesis platform has been developed to enable self-optimization of reaction conditions of organic electrochemical reactions using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and gas chromatography (GC) as online real-time monitoring techniques. We have overcome the challenges in using ATR FT-IR as the downstream analytical methods imposed when a large amount of hydrogen gas is produced from the counter electrode by designing two types of gas–liquid separators (GLS) for analysis of the product mixture flowing from the electrochemical reactor. In particular, we report an integrated GLS with an ATR FT-IR probe at the reactor outlet to give a facile and low-cost solution to determining the concentrations of products in gas–liquid two-phase flow. This approach provides a reliable method for quantifying low-volatile analytes, which can be problematic to be monitored by GC. Two electrochemical reactions the methoxylation of 1-formylpyrrolidine and the oxidation of 3-bromobenzyl alcohol were investigated to demonstrate that the optimal conditions can be located within the pre-defined multi-dimensional reaction parameter spaces without intervention of the operator by using the stable noisy optimization by branch and FIT (SNOBFIT) algorithm.