Search results for "elektrodit"

Adiabatic versus non-adiabatic electron transfer at 2D electrode materials

2021

2D electrode materials are often deployed on conductive supports for electrochemistry and there is a great need to understand fundamental electrochemical processes in this electrode configuration. Here, an integrated experimental-theoretical approach is used to resolve the key electronic interactions in outer-sphere electron transfer (OS-ET), a cornerstone elementary electrochemical reaction, at graphene as-grown on a copper electrode. Using scanning electrochemical cell microscopy, and co-located structural microscopy, the classical hexaamineruthenium (III/II) couple shows the ET kinetics trend: monolayer > bilayer > multilayer graphene. This trend is rationalized quantitatively through th…

Precipitation and Calcination of High-Capacity LiNiO2 Cathode Material for Lithium-Ion Batteries

2020

This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These a…

Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid-liquid interfaces.

2020

Multi-electron, multi-proton transfer is important in a wide spectrum of processes spanning biological, chemical and physical systems. These reactions have attracted significant interest due to both fundamental curiosity and potential applications in energy technology. In this Perspective Review, we shed light on modern aspects of electrode processes in the 21st century, in particular on the recent advances and challenges in multistep electron/proton transfers at solid–liquid interfaces. Ongoing developments of analytical techniques and operando spectrometry at electrode/electrolyte interfaces and reliable computational approaches to simulate complicated interfacial electrochemical reaction…

Preparation of Highly Porous Carbonous Electrodes by Selective Laser Sintering

2019

Selective laser sintering (SLS) 3D printing was utilized to fabricate highly porous carbonous electrodes. The electrodes were prepared by using a mixture of fine graphite powder and either polyamide-12, polystyrene, or polyurethane polymer powder as SLS printing material. During the printing process the graphite powder was dispersed uniformly on the supporting polymer matrix. Graphite’s concentration in the mixture was varied between 5 and 40 wt % to find the correlation between the carbon content and conductivity. The graphite concentration, polymer matrix, and printing conditions all had an impact on the final conductivity. Due to the SLS printing technique, all the 3D printed electrodes …

Activated Cashew Carbon-Manganese Oxide Based Electrodes for Supercapacitor Applications

2023

The current global energy challenge which affects most developing countries in particular, is of major source of concern today. The availability of less expensive techniques of storing excess generated energy is critical to the success of the renewable energy roadmaps implementation. In this study, hydrothermal and chemical leaching methods have been used to synthesize MnO2 nanoparticles using KMnO4 and MnSO4 as precursors at 140 °C and from natural local manganese ore. Activated Carbon (ACF) have also been produced from agricultural Cashew biomass waste, through a physical carbonization and KOH activation process using temperatures of 700 °C – 900 °C for periods between 1-2 hours. The as-p…

Carbon nanotube field-effect devices with asymmetric electrode configuration by contact geometry

2014

We have studied experimentally the conductive properties of single walled carbon nanotube (SWNT) based field-effect type devices, with different contact geometries at the connecting electrode. The device designs are asymmetric with one end of the SWNT having the metal electrode deposited on top and immersing it, while at the other end, the SWNT is on top of the electrode. The devices were made with either gold or palladium as electrode materials, of which the latter resulted in different behavior of the different contact types. This is argued to be caused by the existence of a thin insulating layer of surface adsorbents on the palladium, possibly Pd5O4, the effect of which is enhanced by th…

Co-precipitation of Mg-doped Ni0.8Co0.1Mn0.1(OH)₂:effect of magnesium doping and washing on the battery cell performance

2023

Co-precipitation of Ni0.8Co0.1Mn0.1(OH)2 (NCM811) and Mg-doped (0.25 wt% and 0.5 wt%) NCM811 precursors is carried out from concentrated metal sulphate solutions. In this paper, the aim is to study the role of magnesium dopant in the co-precipitation step of NCM811, the cathode active material and further the Li-ion battery cell performance. Based on the results, magnesium was fully co-precipitated in the NCM811 precursors, as expected from thermodynamic calculations. The presence of magnesium in these precursors was also confirmed by several characterization methods and magnesium was evenly distributed in the sample. It was observed that tapped density decreased and surface area increased …

Measurements on electric breakdown in dielectric barriers between carbon nanotubes and electrodes

2009

Electrocatalytic rate constants from DFT simulations and theoretical models: Learning from each other

2022

Electrochemical interfaces present an extraordinarily complex reaction environment and several, often counter-acting, interactions contribute to rate constants of electrocatalytic reactions. We compile a short review on how electrode potential, solvent, electrolyte, and pH effects on electrocatalytic rates can be understood and modelled using computational and theoretical methods. We address the connections between computational models based on DFT and (semi)analytical model Hamiltonians to extract physical or chemical insights, identify some omissions in present DFT simulation approaches and analytic models, and discuss what and how simulations and models could learn from each other. peerR…

Monikanavaelektrodilla mitattu alueellinen lihasaktiivisuus eri nivelkulmilla isometrisessä tahdonalaisessa ja sähköstimulaatiolla aiheutetussa lihas…

2014

Elektromyografiaa (EMG) on käytetty jo vuosikymmeniä lihasaktiivisuuden tutkimisessa, mutta edelleen siihen liittyy useita epävarmuustekijöitä. Yksi näistä on EMG-signaalin normalisointi eli kuinka elektromyogrammi tulisi normalisoida erilaisissa suorituksissa ja millainen referenssisupistus tulisi valita normalisointiyhtälön viitearvoksi. Normalisointia pidetään edellytyksenä EMG-signaaleja vertailevalle analyyseille, jos signaalit ovat rekisteröity eri lihaksista, eri henkilöiltä tai samasta lihaksesta eri ajankohtina. Normalisointimenetelmän valinnalla on olennainen vaikutus tutkimuksen kohteena olevan suorituksen tulosten tulkintaan ja validiteettiin. Tämän tutkimuksen tarkoituksena oli…