Showing papers in "Energy technology in 2022"

High‐Entropy Materials for Water Electrolysis

Abstract: Green hydrogen production by renewables-powered water electrolysis holds the key to energy sustainability and a carbon-neutral future. The sluggish kinetics of water-splitting reactions, namely, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), however, remains a bottleneck to the water electrolysis technology. High-entropy materials, due to their compositional flexibility, structural stability, and synergy between various elemental components, have recently aroused considerable interest in catalyzing the water-splitting reactions. Herein, a timely review of the recent achievements is provided in high-entropy materials for water electrolysis. An overview of different kinds of high-entropy materials for catalyzing the HER and OER half-reactions is introduced, followed by a discussion of theoretical and experimental efforts in understanding the fundamental origins of the enhanced catalytic performance observed on high-entropy catalysts. Various materials design strategies, including control of size and shape, construction of a porous structure, engineering of defect, and formation of hybrid/composite structure, to develop high-entropy catalysts with improved catalytic performance are highlighted. Finally, the remaining challenges are pointed out and the corresponding perspectives to address these challenges are put forward to promote the development of the research field of high-entropy water-splitting catalysts.

A New alcohol‐soluble polymer PFN‐ID as cathode interlayer to optimize performance of conventional polymer solar cells by increasing electron mobility

Abstract: A new alcohol-soluble polymer PFN-ID is successfully synthesized by combining N,N-di(2-ethylhexyl)-6,6′-dibromoisoindigo and an amino-containing fluorene subunits, and applied to polymer solar cells (PSCs) with PTB7-Th:PC71BM as an active layer. The n-type backbone of the PFN-ID improves electron transfer performance and thus optimizes device performance. The PSCs with PFN-ID as cathode interfacial layers (CILs) have significantly improved compared to the device without the interface layer, especially the optimum power conversion efficiency (PCE) of PSCs reaches up to 9.24%, which is 1.62 times higher than that of devices without CILs. The I–V curves show that the introduction of the n-type backbone leads to a significant increase in the conductivity of PFN-ID compared to PFN. The UV photoelectron spectroscopy and Mott–Schottky curves further confirm that PFN-ID can decrease the work function of Al electrode, and increase its built-in potential, giving higher open-circuit voltage. The resulting conventional PSCs using PFN-ID as cathode interlayer achieve high photovoltaic performance, and the research results can provide a new strategy for the advancement of PSCs.

Electrodeless nanogenerator for dust recover

Abstract: Triboelectric nanogenerator (TENG) has the advantages of low cost, low weight, simple structure, and high efficiency. It is a promising low-frequency mechanical energy capture technology, which shows great potential in dealing with energy and environmental crisis and promoting new electronic products. TENGs have demonstrated irreplaceable design freedom over traditional electronic devices, including its ability to work independently of electrodes. In fact, the displacement current is an unreal current, it can work independently without electrodes. Moreover, due to the lack of “shielding effect” of the electrode, the surface potential can be larger than devices worked with electrodes. Here, based on TENG’s high-voltage characteristic without electrode, the application of dust removal is explored, and a kind of electrodeless polyethylene (PE) triboelectric blackboard eraser was demonstrated as an example, which can effectively restrain the flying of chalk dust (limit the dust diffusion within 0.648 m). The electrostatic charge decayed blackboard eraser can be recharged by the electrodeless TENG without requirement of electrodes establishment. In fact, contact electrification may happen frequently in natural environment, and further design may be achieved without the limitation of electrodes. This article is protected by copyright. All rights reserved.

Machine‐Learning Analysis of Small‐Molecule Donors for Fullerene Based Organic Solar Cells

Abstract: In recent years, development in organic solar cells speeds up and performance continuously increases. From the last few years, machine learning gains fame among scientists who are researching on organic solar cells. Herein, machine learning is used to screen the small-molecule donors for organic solar cells. Molecular descriptors are used as input to train machine models. A variety of machine-learning models are tested to find the suitable one. Random forest model shows best predictive capability (Pearson's coefficient = 0.93). New small-molecule donors are also designed from easily synthesizable building units. Their power conversion efficiencies (PCEs) are predicted. Potential candidates with PCE > 11% are selected. The approach presented herein helps to select the efficient materials in short time with ease.

Emerging study on lead‐free hybrid double perovskite (CH 3 NH 3 ) 2 AgInBr 6 : Potential material for energy conversion between heat and electricity

Abstract: Minimal cost, huge area, high throughput, high performance of photovoltaic panels, prolonged lifespan, and less toxicity are vital aspects when transitioning photovoltaic technology from lab-scale production to industrial implementations. A new class of materials typically known as hybrid halide double perovskites (HHDPs) has emerged as a possible alternative for the replacement of toxic lead in crystal lattice for realizing lead-free, stable, and high-performance perovskite solar cells (PSCs). An ab initio analysis of (MA)2AgInBr6 HHDP via the WIEN2K code is conducted. It is found that this material has a direct bandgap of 3.85 eV having excellent optical properties in the UV region. The calculated thermodynamic parameters confirm its thermal stability at different temperatures and pressure. Its figure of merit is more than unity at room temperature as well as higher temperature ranges, so this material will be useful in thermoelectric (TE) devices as a TE material.

Learning from fullerenes and predicting for Y6. Machine learning and high‐throughput screening of small molecule donors for organic solar cells

Abstract: In recent years, research on the development of organic solar cells has increased significantly. For the last few years, machine learning (ML) has been gaining the attention of the scientific community working on organic solar cells. Herein, ML is used to screen small molecule donors for organic solar cells. ML models are fed by molecular descriptors. Various ML models are employed. The predictive capability of a support vector machine is found to be higher (Pearson's coefficient = 0.75). The best small donors with fullerene acceptors are selected to pair with Y6. New small molecule donors are also designed taking into account quantum chemistry principles, using building units that are searched through similarity analysis. Their energy levels and power conversion efficiencies (PCEs) are predicted. Efficient small molecule donors with PCE > 13% are selected. This design and discovery pipeline provides an easy and fast way to select potential candidates for experimental work.

Evaluation of deformation behavior and fast elastic recovery of lithium‐ion battery cathodes via direct roll gap detection during calendering

Abstract: Calendering is the state-of-the-art process for electrode compaction in lithium-ion battery manufacturing through which the final electrode structure is defined. As the electrode structure determines the electrical und electrochemical transport properties, it is essential to develop a deep understanding of the interdependence between the calendering process and the deformation behavior of the electrodes. Therefore, a novel method for the investigation of the deformation behavior of electrodes, especially the springback (SB) effect, through direct-gap detection within the calendering machine, is developed. With this installation, it is possible to directly access the maximum compression of the electrodes during calendering. With this approach, two different variations of cathodes, a variation of mass loading and a variation of binder weight content, based on lithium nickel manganese cobalt oxide (NMC622), are manufactured and investigated. Moreover, an empirical model is introduced, allowing the estimation of the SB for NMC622 cathodes considering different mass loadings and cathode compositions. Due to more space for particle rearrangement, cathodes with higher mass loading show a lower SB effect. Adding binder leads to higher plastic deformation and thus lowers also the SB effect of the electrodes.

Review and Development of anode electrocatalyst carriers for direct methanol fuel cell

Abstract: Direct methanol fuel cell (DMFC) can be used as a promising portable power device due to its excellent energy conversion efficiency and low pollutant emissions. The performance of DMFC largely depends on the anode electrocatalyst for methanol oxidation reaction (MOR). As an important part of the electrocatalyst, the carrier greatly affects the activity and stability of the electrocatalyst. Herein, the research progress of carbonaceous carriers (such as activated carbon, nanostructured carbon), noncarbonaceous carriers (metal compounds), and conducting polymers in DMFC is reviewed. Furthermore, an overview of the development of self-supporting carriers for flexible DMFC electronics is presented. Its role as the most ideal DMFC carrier in the future provides new ideas for the challenges and development of the commercialization of flexible DMFC.

Design and Simulation of Single‐Electrode Mode Triboelectric Nanogenerator Based Pulse Sensor for Healthcare Applications using COMSOL Multiphysics

Abstract: The advancement in triboelectric nanogenerator technology leads to numerous advantages in various fields, especially in biomedical and healthcare applications. Theoretical modeling and simulation of sensors is the initial step for an optimized cost-effective real-time sensor fabrication which reduces the wastage of materials and rapid prototyping, giving an expected sensor performance. Herein, a theoretical model of single-electrode triboelectric nanogenerator is presented which finds its application in healthcare monitoring as a wearable flexible pulse sensor to measure the wrist pulse for disease diagnosis. The device optimization in terms of structure, material and output performance is done based on the said application. A brief study of the operating principle of the sensor along with the factors affecting the output is discussed in this work. The design is conceptually investigated considering the electrostatic shield effect from the contact electrode. The output performance variation concerning the plain and micro-structured triboelectric surface is also determined in terms of open-circuit voltage of ≈16.95 and ≈21.63 V, respectively, and also a short-circuit charge of ≈181.81 and ≈196.57 pC, respectively. The superior output performance even for smaller wrist pulse displacement range can serve as a significant assistance for the rational plan of the device structure.

Recent Advances in Enhanced Performance of Ni‐Rich Cathode Materials for Li‐Ion Batteries: A Review

Abstract: High energy Li-ion batteries (LIBs) have garnered substantial consideration in recent years for their utilization in many fields like communication, transportation, and aviation. As the cathode is the crucial component of LIBs, so by enhancing its electrochemical performance, the capacity, rate capability, as well as cyclability of batteries can be enhanced. Ni-rich cathode materials (LiNi x Mn y Co1−x−y O2, x ≥ 0.5) have been accredited for their benefits in enhanced capacity, high working voltage, and low manufacturing cost. The high Ni content is accountable for the exceptional capacity but the utilization in the commercialized LIBs is mired by their electrochemical cycling issues like capacity fading, voltage decay, and safety hazard. To overcome these obstructions, a variety of methodologies have been adopted like doping, coating, and comodification of these cathode materials. An inclusive study of Ni-rich cathode materials, their degradation mechanism, and the strategies is conferred, which have been employed in recent years to overcome the challenges faced by these materials in their commercialization.

Binder free synthesis of mesoporous nickel tungstate for Aqueous Asymmetric Supercapacitor Applications: Effect of film thickness

Abstract: Nickel tungstate (NiWO4) thin films of different thicknesses were synthesized using binder free successive ionic layer adsorption and reaction (SILAR) method at ambient temperature and succeeded by calcination at temperature of 727 K. The physico-chemical characterizations of NiWO4 thin films were carried out using different techniques. The electrochemical performances of NiWO4 films were evaluated in 2 M KOH electrolyte using standard three electrode system. The specific capacitance of 1536 F g-1 at the current density of 2 A g-1 was obtained for NiWO4 film. The film exhibited excellent electrochemical stability of 87% after 5000 galvanostatic charge discharge (GCD) cycles at the current density of 3 A g-1. This study highlights use of SILAR deposited NiWO4 thin films as a cathode in aqueous asymmetric supercapacitors (ASC). Asymmetric supercapacitor device NiWO4/KOH/Fe2O3 exhibited a specific capacitance of 115 F g-1 at 2 A g-1, and specific energy of 23Wh kg-1 at specific power of 1.2 kW kg-1. The device showed remarkable electrochemical cycling stability (78% capacitance retention after 5000 GCD cycles). The SILAR deposited NiWO4 thin films are expected to emerge as a potential candidate for supercapacitors. This article is protected by copyright. All rights reserved.

Novel Star‐Shaped Benzotriindole‐Based Nonfullerene Donor Materials: Toward the Development of Promising Photovoltaic Compounds for High‐Performance Organic Solar Cells

Abstract: The development of novel photovoltaic materials for solar cell applications is a fascinating area of current research. Star-shaped materials with promising photovoltaic features have attracted scientists for boosting the progress of organic solar cells (OSCs). Herein, seven novel star-shaped molecules (DA1-DA7) are developed quantum chemically from the experimentally synthesized BTI(2 T-DCV-Hex)3 molecule. The open-circuit voltage (Voc), transition density matrix heat maps, density of state (DOS), overlap DOS, frontier molecular orbital, UV−visible, binding energy (Eb), hole (λh) and electron (λe) reorganizational energy, and highest occupied molecular orbital (HOMO)donor−lowest unoccupied molecular orbital (LUMO)PC61BM charge transfer analysis are performed to explore the optoelectronic properties. Newly developed molecules exhibit promising optoelectronic features with reduced energy gap (2.43−1.97 eV), transition energy (1.89−1.45 eV), λe (0.00149328−0.00101405 Eh), λh (0.0066471−0.0028843 Eh), broadened λmax (655−856 nm), and high Voc (2.07−1.65 V), as compared with reference BTI(2 T-DCV-Hex)3 values 2.82 eV, 2.28 eV, 0.00176501 Eh, 0.0060877 Eh, and 544 nm, 1.65 V, respectively. The developed molecules have proficient hole and electron transfer mobilities and can serve as best candidates when blended with PC61BM film. These eye-catching results recommend the novel star-shaped compounds for future development of high-performance OSCs.

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

Abstract: The electrochemical urea oxidation reaction (UOR) is the performance-limiting half reaction of urea electrolysis for producing renewable hydrogen energy. Nevertheless, the essence of electrode function mechanism of catalysts remains unclear. Therefore, design and optimization of catalysts are restricted. Herein, an in situ Raman spectroscopy method is employed to directly measure the electrode properties of the NiCo double hydroxides (NiCo DHs) under working conditions. Given definitely evidence, the evolution process of in situ Raman spectra shows that the Ni element is converted to NiOOH under UOR potentials, while the Co dopant is converted to CoOOH and further to higher-valence CoO2 species. Obviously, the catalytically active phase toward UOR is really a complex NiOOH–CoOOH–CoO2 phase. Accurately matched spectral wavenumbers and electrochemical measurements of the catalytic electrodes explicitly reveal that the addition of Co assuredly reduces the onset potential for electroactive NiOOH formation. The Raman results also indicate effects of the NiO bond elongation and increased disorder caused by Co doping. Herein, an important understanding and new mechanistic perspectives for the electrode reaction process of UOR with NiCo binary catalysts are provided.

Hybrid Piezoelectric and Triboelectric Nanogenerators for Energy Harvesting and Walking Sensing

Abstract: With the increasing improvement of wearable gadgets, nanogenerators have received significant attention in recent years. Herein, a hybrid piezoelectric and triboelectric nanogenerators (PTNG) for generating energy and monitoring is developed. The PTNG uses magnetic force to implement the opposing force in the sliding mode between the Kapton and copper/aluminum layers for the triboelectric part and polyvinylidene fluoride strips. The triboelectric part with copper set up in PTNG in mode 2 (capsule with electrode layer) is found with the maximum voltage in the open circuit and the peak power of approximately 12 μW for the triboelectric part. The piezoelectric part in PTNG is found with the maximum voltage V max = 20.8 V in the open circuit and the peak power of approximately 70 μW. In this design, a self-powered walking sensing system is developed utilizing the PTNG for analyzing behavior of the human by walking on the treadmill. A test is conducted with different speeds of the treadmill, and the maximum hybrid open-circuit voltage at 8 km h−1 is 21.9 V. This approach may present an innovative purpose for creating high-performance and manageable energy harvesting gadgets with improved power output from human motions.

Drying of NCM cathode electrodes with porous, nanostructured particles versus compact solid particles: Comparative study of binder migration as a function of drying conditions

Abstract: The concentration distribution of the polyvinylidene fl for these electrodes faster drying. Cell tests with half cells show that after increasing the drying rate by more than 350%, the discharge capacity of the electrodes consisting of solid NCM is by about 63% at while for the electrodes made of porous material no reduction is

Solar‐Driven Airflow Enhanced All‐Daytime Solar Steam Generation Based on Inverse‐Bowl‐Shaped Graphene Aerogels

Abstract: Solar steam generation (SSG) is a promising approach to solve the shortage of fresh water resources. Despite intensive research on photothermal materials, the SSG performance is still unsatisfactory for practical applications. Moreover, the actual solar trajectory is a semicircular arc, resulting in a continuous change of the incident angle, which is often ignored in previous reports. Herein, an inverse-bowl-shaped graphene aerogel (IBGA) is synthesized as the photothermal component for the SSG, which can always maintain a high water evaporation rate with the change of the incident angles. Furthermore, a solar-driven airflow is introduced based on a modified Stirling engine to enhance the SSG performance. The SSG device based on IBGA with solar-driven airflow exhibits a high evaporation rate of 2.46 kg m−2 h−1 under 1 sun irradiation. The outdoor experiments demonstrate that an SSG device with 1 m2 of IBGA can collect 15 kg freshwater on a sunny day, showing great potential for seawater desalination and wastewater treatments in practical applications.

Detection of Lithium‐ion cells degradation through deconvolution of EIS with Distribution of Relaxation Time

Abstract: Herein, a methodology to investigate aging of commercial cylindrical Li-ion cells is introduced. Distribution of relaxation time (DRT) method is applied to deconvolute electrochemical impedance spectroscopy (EIS) measurements and separate those polarization effects that are usually overlapped in the frequency domain by means of a peak-based representation. Half-cells are built at the beginning and end of life to link the electrochemical and aging processes occurring at anode and/or the cathode sides. Moreover, lab-made full-cells are exploited to verify the reproducibility when compared with cylindrical cells. The results of an extensive analysis of around 500 EIS spectra return an unambiguous attribution of different electrochemical processes to different time constants and ultimately to different DRT peaks. Digital imaging validates graphite degradation, mainly related to lithium plating. Scanning electron microscopy validates the degradation at NMC cathode, mainly attributed to particle cracking. It is concluded that DRT peaks allow to characterize cell aging and their tracking can help to develop more reliable state of health estimators.

Exploration of highly porous biochar derived from dead leaves to immobilize LiOH·H 2 O nanoparticles for efficient thermochemical heat storage applications

Abstract: The inadequate utilization of low-grade energy from industrial waste heat and solar energy calls for an efficient thermochemical heat storage material. The fabrication of a low-cost but highly efficient composite comprising highly porous biochar and LiOH·H2O nanoparticles for heat storage applications is reported. The biochar is prepared by the KOH-assisted pyrolysis of dead banyan leaves, and its microstructure and surface properties can be finely tuned by varying the KOH-to-biomass ratio. Such biochar can be mediated to possess a large specific surface area and total pore volume reaching as high as 1255.03 m2 g−1 and 3.65 cm3 g−1, respectively, superior to most previously reported biochar/biocarbon derived from different kinds of waste biomass. Besides, adequate functional groups and a hierarchical porous structure consisting of micropores and mesopores are demonstrated in the prepared biochar. The subsequent hydrothermal reaction with a short duration yields a biochar-LiOH·H2O composite, where LiOH·H2O can be homogeneously immobilized with a nanoscale size within the porous biochar matrix. Thus, an enormous biochar/LiOH·H2O nanoparticles interface can be obtained, resulting in fast hydration reactions with water molecules. Consequently, a significant heat storage density of as high as 3089.6 kJ kg−1 is achieved within only 10 min, outstripping some recently reported thermochemical heat storage systems.

Effect of Nickel Precursor on the Catalytic Performance of Graphene Aerogel‐Supported Nickel Nanoparticles for the Production of CO _<i>x</i> ‐free Hydrogen by Ammonia Decomposition

Abstract: Graphene aerogel (GA), a promising porous material with high specific surface area and electrical conductivity, is utilized to disperse nickel nanoparticles to reach high catalytic activity in COx-free hydrogen production from ammonia. Ni(NO3)2·6H2O and Ni (II) acetylacetonate (Ni(acac)2) were considered as metal precursors and the pH of the impregnation solution was varied to investigate the effects on the catalytic properties of the GA-supported nickel catalysts. Data showed that the best dispersion and homogeneity, as well as the catalytic performance, is achieved with Ni(acac)2. An average Ni nanoparticle size of 13.6 ± 4.3 nm was obtained on the GA-supported catalyst prepared by using Ni(acac)2 dissolved in an impregnation solution with a pH of 10.2. This catalyst with a Ni loading of 11.1 wt% provided an ammonia conversion of 70.2% at a space velocity of 30 000 mL NH3 gcat−1 h−1 and 600 °C corresponding to a hydrogen production rate of 21.5 mmol H2 gcat−1 min−1. Data illustrated that the difference between the point of zero charge of the support and the pH of the impregnation solution set by the type of the Ni precursor is a major parameter controlling the metal dispersion and the consequent catalytic activity.

Wearable Electronics Powered by Triboelectrification Between Hair and Cloth for Monitoring Body Motions

Abstract: Diverse triboelectric nanogenerators (TENGs) have been extensively applied in self-powered wearable electronics. The TENG-based demonstration by using a partial or whole human body as a triboelectric material is rare, though wearable electronics plays a more and more pivotal role in portable intelligent medicine. Human hair, as part of the human body, can be a component of a TENG-based wearable system. In this paper, we propose a novel body-based TENG configuration made of human hair and polydimethylsiloxane (PDMS) coated carbon cloth. Due to triboelectrification between the hair and the PDMS layer, the output voltage can deliver 1.713 V and 0.377 V in the vertical contact-separation mode and sliding mode, respectively. In addition, a self-powered application based on the hair-based TENG for actively monitoring motion state by comparing the amplitude and frequency of the output voltages has been successfully demonstrated. This study broadens the application of body-based TENGs and provides a promising and feasible strategy for developing smart health monitoring. This article is protected by copyright. All rights reserved.

Methane Pyrolysis in a Liquid Metal Bubble Column Reactor – a Model Approach Combining Bubble Dynamics with By‐Product and Soot Formation

Abstract: Methane pyrolysis is a promising bridging technology to mitigate the effects of climate change. By decarbonizing natural gas, hydrogen can be produced from fossil fuels without creating CO2 emissions. The focus of future process optimization should not only be on the hydrogen yield and the energy efficiency but also on the carbon products and possible byproduct formation. During methane pyrolysis in a liquid metal (LM) bubble column reactor, at least two very distinct types of carbon are synthesized: soot particles and graphene-like carbon sheets. A model is presented that couples a description of bubble dynamics in a LM bubble column reactor with a kinetic mechanism, originally developed for the combustion of natural gas that includes byproduct and soot formation. The model is validated by comparing it with an experimental dataset that covers a broad range of process conditions and the implications for carbon and byproduct formation are discussed. The good agreement of model results and experimental data shows that the combustion kinetic mechanism may be applied to methane pyrolysis and that the selected way of modeling bubble fluid dynamics in LM results in a good estimation of the actual bubble residence time in the optically nonaccessible liquid.

Efficiency and Stability Analysis of 2D/3D Perovskite Solar Cells Using Machine Learning

Abstract: A dataset containing 599 data points from 146 publications on 2D/3D perovskite solar cells is analyzed using machine learning. The predictive models are developed for power conversion efficiency (PCE) using eXtreme Gradient Boosting regression, random forest regression and artificial neural networks while association rule mining is used to analyze the stability data to identify the descriptors leading to high stability 2D/3D cells. A predictive model is also developed for the bandgap to predict the missing values in the dataset for the use in PCE predictions. Models for both bandgap and PCE predictions are quite successful. The thickness of inorganic layer (n), radius of anion (R x ), and 2D cation (R m) are found to be the most important descriptors for bandgap predictions; n and R m, together with the bandgap, are found to be deterministic for PCE in regular cells while the bandgap, n, and conduction band energy of hole transport layer are the most influential descriptors in inverted structures. Association rule mining analysis for the stability indicates that the cells with layered perovskite structures are more stable while the 2D and 3D cations leading to the most stable cells are found to be butylammonium and formamidinium-Cs mixed cation respectively.

Rotary Screen Printed Metallization of Heterojunction Solar Cells – Towards High Throughput Production with Very Low Silver Laydown

Abstract: Within this work, first bifacial silicon heterojunction solar cells with rotary screen printed front and rear side metallization are demonstrated. The high-throughput metallization process is carried out using an innovative rotary printing demonstrator machine with short process cycle times down to 0.65 s per cell. Furthermore, we demonstrate a very low total silver consumption of only 6 to 9 mg/Wp for the fully metallized bifacial silicon heterojunction solar cells. Using a newly developed screen simulation approach, the the utilized fine line rotary and flatbed screens are analyzed regarding their suitability for fine line metallization and verified using in-depth analysis of the geometrical and electrical properties of printed and cured metallization. The best group of fully rotary screen printed cells obtained a mean conversion efficiency of ηRSP,avg = 21.7% which is close to the flatbed screen printed reference group with ηFSP,avg = 22.1%. Using a hybrid approach with a rotary screen printed grid on the rear side and flatbed screen printed grid on the front side, a mean conversion efficiency of ηhyb,avg = 22.0% is obtained with a very low total silver consumption of only 9 mg/Wp. This article is protected by copyright. All rights reserved.

Understanding the Cathode‐Electrolyte Interphase in Lithium‐Ion Batteries

Abstract: The electrode–electrolyte interface is one of the major components enabling Li-ion batteries (LIBs) to function reversibly. Often, the solid–electrolyte interphase (SEI) at the anode is regarded as the key interface that determines the cycle life, capacity fade, and overall safety of batteries. There are a plethora of SEI literatures that exist; however, the cathode–electrolyte interphase (CEI) remains relatively unexplored. Unlike in the case of SEI, a detailed understanding of CEI formation and its association with battery performance is not present. This review gives insight into the recent progress in understanding the CEI in LIBs. Though there is a relative dearth of literature, the CEI is generally considered as a heterogeneous multicomponent film formed due to the decomposition of electrolyte at the cathode surface. Besides understanding the thermodynamic properties and relevant kinetic reactions, one of the main challenges lies in developing and stabilizing the CEI layer due to its complex structural composition. Extensive research efforts to engineer a stable CEI are reviewed, including the use of electrolyte additives, artificial engineering, and heteroatom doping of cathode. Furthermore, promising characterization techniques and future outlook in forming a robust CEI for both existing LIB and post-LIB systems are highlighted.

Catalysis in Solid Hydrogen Storage: Recent Advances, Challenges and Perspectives

Abstract: Catalysis is at the core of previous energy transition. It has enabled the use of oil and natural gas as our primary energy sources in unprecedented ways and led to feedstocks enabling exceptionally high living standards in human history. In a decarbonized economy with hydrogen as the new energy vector, catalysis is already playing a key role in producing hydrogen. However, catalysts for the effective storage of hydrogen must be advanced. Many solid hydrogen storage materials such as magnesium-based hydrides, alanates, and/or borohydrides display promising hydrogen densities far superior to the current state of compressed or liquid hydrogen. These solid materials have thermodynamic and kinetic barriers which severely hinder their practical hydrogen uptake and release. To date, most of these barriers for solid hydrides (especially boron or nitrogen compounds) are modified via catalysis; however, the catalytic species per se and their roles are obscure. Herein, a comprehensive overview of various catalysts for solid hydrogen storage materials, their catalytic roles, and the underpinning mechanisms is provided. The current state of knowledge is critically reviewed and gaps where further research intensification is needed to support rapid hydrogen generation and storage in solid materials for the emerging hydrogen economy are identified.

Deep reinforcement learning based on driver experience embedding for energy management strategies in hybrid electric vehicles

Abstract: Reinforcement learning (RL) is a solution with great potential for hybrid electric vehicle (HEV) energy management strategies (EMS). However, traditional deep reinforcement learning (DRL) suffers from inefficiency and poor stability during random exploration in action space, so it is necessary to model some advanced driver experience knowledge and combine it with DRL. Herein, an advanced driver experience (DE) model of traffic congestion level and power matching is constructed based on fuzzy clustering and embedded into DRL. The results show that the DE embedding improves the training convergence efficiency of DRL on a power-split HEV model, where it improves the convergence of the deep deterministic policy gradient (DDPG) by 46.2%. As DE can better adjust engine operating points and vehicle drive modes under various driving cycles, it enables DDPG to improve fuel economy by ≈6.29% while maintaining the terminal state of charge. This study aims to improve the efficiency of action space exploration and optimize the DRL learning strategy, so as to provide a theoretical basis for the design and development of EMS.

Perylenediimide/Graphite Foil Based Electrode Materials with Outstanding Cycling Stability for Symmetric Supercapacitor Device Architectures

Abstract: Herein, pyridine functionalized naphthalenediimide (NDI-Py) and perylenediimide (PDI-Py) derivatives are synthesized and characterized using modern techniques. NDI-Py and PDI-Py in combination with graphite foil (GF) are employed as electrode materials for supercapacitor (SC) applications. Under the three-electrode system, the electrode materials based on NDI-Py/GF and PDI-Py/GF composite electrode exhibit specific capacitance (C sp) of about 118 and 179 F g−1 at 5 mV s−1 from cyclic voltammetry (CV) and 132 and 197 F g−1 at 1 A g−1 from galvanostatic charge–discharge (GCD) curves. The electrochemical performance behaviors of these electrodes are mainly contributed by surface reactions along with the Faradaic redox reactions such as pseudocapacitance. The corresponding two-electrode symmetric SC device based on PDI-Py/GF//PDI-Py/GF exhibits a high energy density of 46 Wh kg−1 at a power density of 3060 W kg−1 at 1 A g−1 current density, which is further retained at 13 Wh kg−1 and 15 300 W kg−1 energy and power density, respectively, at 5 A g−1 current density. Moreover, the symmetrical SC device based on PDI-Py/GF//PDI-Py/GF shows outstanding cyclic stability for 10 000 charge–discharge cycles while maintaining 95% of the original capacitance.

A review of high‐temperature foam for improving steam flooding effect: mechanism and application of foam

Abstract: With the exploitation of light oil approaching saturation, the exploitation of heavy oil is of particular importance. Thermal recovery technology is typically used in heavy oil recovery, such as steam flooding (SF), steam-assisted gravity drainage, and cyclic steam stimulation. However, SF technology brings problems such as gravity overlap, viscous fingering, and channeling, reducing the sweep efficiency and oil recovery efficiency. Some studies have proposed that foam and steam should be injected into the reservoir together to plug, turn, and reduce viscosity. Heavy oil production occurs mostly under high-temperature conditions, which require that the foaming agents have good foaming ability in this environment. The generated foam should have good stability. Meanwhile, the mechanism of steam foam enhancing oil recovery (EOR) also changes. Therefore, the research on the mechanism and application of steam foam technology is discussed. First, the basic theory of foam is introduced, and the research on the mechanism of steam foam EOR is discussed. Second, the application of steam foam in the laboratory and the field is summarized. Finally, the full text is summarized and some prospects are made, to provide some help for future research.

Rechargeable aluminum‐air batteries based on aqueous solid‐state electrolytes

Abstract: The feasibility to recharge aluminum-air cells realized with a dual water-based electrolyte without separator is demonstrated. The dual electrolyte, made of polyvinyl alcohol and Xanthan gum, has a different water content, lower at the anodic interface, where parasitic reactions involving hydrogen production play a crucial role in hindering metal re-deposition, and higher at the cathode side, where water, depending on the pH, allows an efficient reduction of oxygen during discharge or the oxygen evolution during cell charging. The galvanostatic cycles show in the first discharge and charge cycles, the characteristic plateau trends of secondary batteries. By electrochemical impedance spectroscopy analysis effected after each discharge/charge phase and by measuring anode and cathode potentials during cycling, it is demonstrated that, during the first cycles, the re-deposition of aluminum is possible by adopting adequate water management in the electrolyte, while the cell malfunctioning in the subsequent cycles is mainly due to the damage of the cathode.