HSE Scientists Have Developed a New Model of Electric Double Layer
This new model accounts for a wide range of ion-electrode interactions and predicts a device's ability to store electric charge. The model's theoretical predictions align with the experimental results. Data on the behaviour of the electric double layer (EDL) can aid in the development of more efficient supercapacitors for portable electronics and electric vehicles. The study has been published in ChemPhysChem.
Many devices store energy for future use, with batteries being among the most well-known examples. They can consistently release energy, maintaining steady power output regardless of existing conditions or load, until fully discharged.
In contrast, supercapacitors deliver power in pulses rather than in a continuous flow. If a battery can be likened to a jar that gradually stores energy for long-term use, then a supercapacitor is like a bucket that can be filled and emptied rapidly. This means that a supercapacitor can store energy for a short duration and release it instantly in a large burst.
The power of a supercapacitor depends on its internal resistance, which is notably high. This enables the supercapacitor to operate with very high currents, almost similar to a short circuit. Such a system is helpful when a quick, powerful charge is needed, and it is used in cars, emergency power systems, and compact devices. This effect is made possible by the accumulation of energy in the supercapacitor through an electric double layer (EDL).
The ability of any capacitor to store charge is determined by the area of its plates, the distance between them, and the type of dielectric material used. Since the electrolyte layer between the plates of a supercapacitor is only a few nanometres thick, and the porous coating on the electrodes provides a large surface area, supercapacitors can significantly surpass traditional capacitors in terms of stored energy.
In real-world conditions, the electric double layer is influenced by chemical interactions occurring at the quantum level. Therefore, it is essential to study both the properties of the electric double layer and the factors that influence it to improve the efficiency of electrical devices.
Scientists at HSE MIEM and the Semenov Research Centre of Chemical Physics have developed a model to describe the electric double layer at the interface between an electrode and an electrolyte solution, using a modified Poisson-Boltzmann equation for calculations. The model considers specific interactions between ions and with surrounding water molecules, the impact of an electric field on the dielectric properties of water, and the limited space available for ions at the electrode surface. This enabled a detailed description of the differential electrical capacitance profiles, measuring how effectively the EDL can accumulate charge as the voltage changes. The higher the differential capacitance, the more charge the layer can hold with small voltage changes.
The study examined aqueous solutions of sodium perchlorate (NaClO₄) and potassium hexafluorophosphate (KPF₆) at the interface with a silver electrode. The resulting model successfully predicted the structure of the electric double layer, providing insights into the capacitance behaviour at various ionic solution concentrations. An important achievement has been the successful application of the model to mixtures of the said electrolytes, demonstrating its versatility and suitability for predicting the behaviour of complex electrochemical systems.
'Our theoretical predictions perfectly match the experimental data. This is important because quantifying differential electrical capacitance during an experiment is not trivial and requires meticulous, time-consuming procedures,' comments Yury Budkov, Leading Research Fellow at the Laboratory for Computational Physics of MIEM HSE and one of the authors of the paper. 'This model will enable the prediction of differential electrical capacitance behaviour in conditions where obtaining experimental data is difficult or impossible.'
This is the first in a series of studies aimed at developing a comprehensive theory of the electric double layer at the metal-electrolyte interface as it relates to real-world systems. In the future, the authors plan to extend the model to include systems with stronger ion-electrode interactions, which are the most prevalent ones.
'Such a model will be able to account for additional factors that influence the operation of modern electrochemical devices. This is important for the development of new supercapacitors that can be utilised in a range of devices, from portable electronics to electric vehicles,' according to Yury Budkov.
See also:
Smoking Habit Affects Response to False Feedback
A team of scientists at HSE University, in collaboration with the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, studied how people respond to deception when under stress and cognitive load. The study revealed that smoking habits interfere with performance on cognitive tasks involving memory and attention and impairs a person’s ability to detect deception. The study findings have been published in Frontiers in Neuroscience.
Russian Physicists Determine Indices Enabling Prediction of Laser Behaviour
Russian scientists, including researchers at HSE University, examined the features of fibre laser generation and identified universal critical indices for calculating their characteristics and operating regimes. The study findings will help predict and optimise laser parameters for high-speed communication systems, spectroscopy, and other areas of optical technology. The paper has been published in Optics & Laser Technology.
Children with Autism Process Auditory Information Differently
A team of scientists, including researchers from the HSE Centre for Language and Brain, examined specific aspects of auditory perception in children with autism. The scientists observed atypical alpha rhythm activity both during sound perception and at rest. This suggests that these children experience abnormalities in the early stages of sound processing in the brain's auditory cortex. Over time, these abnormalities can result in language difficulties. The study findings have been published in Brain Structure and Function.
Smartphones Not Used for Digital Learning among Russian School Students
Despite the widespread use of smartphones, teachers have not fully integrated them into the teaching and learning process, including for developing students' digital skills. Irina Dvoretskaya, Research Fellow at the HSE Institute of Education, has examined the patterns of mobile device use for learning among students in grades 9 to 11.
Working while Studying Can Increase Salary and Chances of Success
Research shows that working while studying increases the likelihood of employment after graduation by 19% and boosts salary by 14%. One in two students has worked for at least a month while studying full time. The greatest benefits come from being employed during the final years of study, when students have the opportunity to begin working in their chosen field. These findings come from a team of authors at the HSE Faculty of Economic Sciences.
Beauty in Details: HSE University and AIRI Scientists Develop a Method for High-Quality Image Editing
Researchers from theHSE AI Research Centre, AIRI, and the University of Bremen have developed a new image editing method based on deep learning—StyleFeatureEditor. This tool allows for precise reproduction of even the smallest details in an image while preserving them during the editing process. With its help, users can easily change hair colour or facial expressions without sacrificing image quality. The results of this three-party collaboration were published at the highly-cited computer vision conference CVPR 2024.
HSE Scientists Have Examined Potential Impact of Nuclear Power on Sustainable Development
Researchers at HSE University have developed a set of mathematical models to predict the impact of nuclear power on the Sustainable Development Index. If the share of nuclear power in the global energy mix increases to between 20% and 25%, the global Sustainable Development Index (SDI) is projected to grow by one-third by 2050. In scenarios where the share of nuclear power grows more slowly, the increase in the SDI is found to be lower. The study has been published in Nuclear Energy and Technology.
Psychologists from HSE University Discovered How Love for Animals Affects Relationships with People
Researchers from HSE University have identified a connection between attachment to pets and attitudes toward nature and other people. The study found that the more joy people derive from interacting with their pets, the more they want to help others. However, love for animals is not always associated with concern for nature. The findings were published in the Social Psychology and Society journal.
HSE Scientists Propose Using Heart Rate Analysis to Diagnose Anxiety and Depression
A group of scientists at HSE University have discovered how anxiety and depression can be diagnosed by analysing heart rate. It turns out that under mental stress, the heart rate of individuals with a predisposition to mental health disorders differs from that of healthy individuals, especially when performing more complex tasks. These changes in cardiovascular parameters can even be detected using a pulse oximeter or a smartwatch. The study findings have been published in Frontiers in Psychiatry.
Researchers at HSE in St Petersburg Develop Superior Machine Learning Model for Determining Text Topics
Topic models are machine learning algorithms designed to analyse large text collections based on their topics. Scientists at HSE Campus in St Petersburg compared five topic models to determine which ones performed better. Two models, including GLDAW developed by the Laboratory for Social and Cognitive Informatics at HSE Campus in St Petersburg, made the lowest number of errors. The paper has been published in PeerJ Computer Science.