Rechargeable Li-ion Batteries Research Articles

Crystal Structure and Li-Fe Order in Synthetic Mg(2-2x)LixFe3+x(SiO4) Olivine Structure.

Olivines are naturally occurring silicates consisting of isolated (SiO4)4- tetrahedra linked through M1O6 and M2O6 octahedra. In this study, we report the structural and crystal-chemical characterization of synthetic olivine crystals containing up to 25% Li-Fe3+ synthesized using the flux growth technique. Based on site scattering, <M1-O> and <M2-O> mean bond lengths, and charge neutrality of the chemical formula, we found a perfect ordering of Li and Fe3+ at the two distinct M1 and M2 sites. Unrestrained linear extrapolation to a hypothetical isostructural LiFe3+(SiO4) composition aligns well with the tabulated ionic radii of Li and Fe3+. Comparison made with the isostructural LiSc(SiO4) reveals that the Li-centered M2O6 octahedron has a significant capacity to distort in order to accommodate structural stresses, due to the relatively weak Li-O bond, while still achieving a bond valence sum that closely matches the formal charge of Li+. This behavior suggests the potential feasibility of an extended Li + Fe3+ for 2 Mg coupled substitution within the olivine structure. The reported structure of the LiFe3+(SiO4) endmember in the literature, despite its apparent matching of cell dimensions and space group with olivine, exhibits extremely unconventional crystal chemical features, raising questions about its validity. Given the importance of the suitability of Li-insertion in LiFeSiO4 as electrodes in rechargeable Li-ion batteries, further studies are needed to investigate its crystal structure and crystal chemistry.

Optimal estimation of SoC, SoH using machine learning models and design of control algorithm for active cell balancing in lithium ion batteries

Abstract Electric vehicles transform the automotive industry by replacing traditional vehicles powered by fossil fuels with less polluting and efficient vehicles. They are powered by rechargeable Li-ion batteries. While there are drawbacks associated with Li-ion battery technology, it's important to note that these challenges can be addressed or mitigated effectively. A battery management system ensures the tracking of all functions performed by the battery. An advanced battery management system should accurately estimate the battery's state of health and state of charge. This paper aims to develop machine learning models for the estimation of the state of health and state of charge and to implement cell balancing in a battery management system. A dataset of battery charging and discharging profiles was used to train various machine learning models for estimation. These methods are computationally less complex than conventional methods. In addition, a cell balancing algorithm is implemented to control the charging and discharging of individual cells in a battery pack and balance the state of charge of each cell. The machine learning solution is created using several machine learning models, including Gradient Boosting, Random Forest, Linear Regression, AdaBoost, and Multi-layer Perceptron. Among the models Gradient Boosting and Random Forest provide good MSE and R2 score. The use of machine learning algorithms for the assessment of state of health and charge estimation combined with the design of an efficient control algorithm for active cell balancing offers significant advancements in the battery management system to optimise the performance, reliability, and useful life of Li-ion batteries. The paper also presents a case study utilising a combination of deep learning-based SoC, SoH estimation algorithms in a simulated data set. A well-designed control algorithm for active cell balancing presents a holistic and effective approach to optimise the performance, reliability, and lifespan of Li-ion batteries.

Aspects of Spodumene Lithium Extraction Techniques

Lithium (Li), a leading cathode material in rechargeable Li-ion batteries, is vital to modern energy storage technology, establishing it as one of the most impactful and strategical elements. Given the surge in the electric car market, it is crucial to improve lithium recovery from its rich mineral deposits using the most effective extraction technique. In recent years, both industry and academia have shown significant interest in Li recovery from various Li-bearing minerals. Of these, only extraction from spodumene has established a reliable industrial production of Li salts. The current approaches for cracking of the naturally occurring, stable α-spodumene structure into a more open structure—β-spodumene—involve the so-called decrepitation process that takes place at extreme temperatures of ~1100 °C. This conversion is necessary, as β-spodumene is more susceptible to chemical attacks facilitating Li extraction. In the last several decades, many techniques have been demonstrated and patented to process hard-rock mineral spodumene. The objective of this review is to present a thorough analysis of significant findings and the enhancement of process flowsheets over time that can be useful for both research endeavors and industrial process improvements. The review focuses on the following techniques: acid methods, alkali methods, carbonate roasting/autoclaving methods, sulfuric acid roasting/autoclaving methods, chlorinating methods, and mechanochemical activation. Recently, microwaves (MWs), as an energy source, have been employed to transform α-spodumene into β-spodumene. Considering its energy-efficient and short-duration aspects, the review discusses the interaction mechanism of MWs with solids, MW-assisted decrepitation, and Li extraction efficiencies. Finally, the merits and/or disadvantages, challenges, and prospects of the processes are summarized.

Functionalized MBene, Ti[formula omitted]BX[formula omitted] (X=Si, Ge, P, As) as potential excellent anode materials for lithium and sodium-ion batteries: A first-principles study

In the search for next-generation energy storage devices, superior-performance alternative electrode materials based on two-dimensional materials for rechargeable metal-ion batteries are essential. Here, we explored group III and IV functionalization of 2D Ti2B, Ti2BX2 (X=Si, Ge, P, As) as anode materials for Li and Na ion batteries using first-principles calculations. The structures had excellent metallic properties and demonstrated energetically favorable adsorptions for metal ions. Analyzing charge transfer and electronic band structures, silicon and phosphorous-functionalized Ti2B (Ti2BSi2 and Ti2BP2) showed the most potential. The energy band diagrams showed that both Ti2BSi2 and Ti2BP2 had metallic characteristics after Li and Na-ion adsorption, which offered considerable advantage for rechargeable-ion batteries. The structures exhibited low energy barriers for Li and Na-ion migration. The minimum energy barriers calculated for Na were 0.08 eV for Ti2BSi2 and 0.24 eV for Ti2BP2. Theoretical specific capacity and open circuit voltage were calculated using maximum layer adsorption. For both Li and Na, high values of specific capacity and low values of open circuit voltage (¡ 1 V) were found. Ti2BSi2 had the best performance, with a theoretical specific capacity of 1647.10 and 1317.68 mA h/g for Li and Na, respectively. Its open circuit voltages for Li and Na were 0.65 and 0.38 V. The insights of this study will be beneficial in fabricating high-performing Ti2BX2-based anodes for rechargeable Li and Na ion batteries.

In-plane staging in lithium-ion intercalation of bilayer graphene

The ongoing efforts to optimize rechargeable Li-ion batteries led to the interest in intercalation of nanoscale layered compounds, including bilayer graphene. Its lithium intercalation has been demonstrated recently but the mechanisms underpinning the storage capacity remain poorly understood. Here, using magnetotransport measurements, we report in-operando intercalation dynamics of bilayer graphene. Unexpectedly, we find four distinct intercalation stages that correspond to well-defined Li-ion densities. Transitions between the stages occur rapidly (within 1 sec) over the entire device area. We refer to these stages as ‘in-plane’, with no in-plane analogues in bulk graphite. The fully intercalated bilayers represent a stoichiometric compound C14LiC14 with a Li density of ∼2.7·1014 cm−2, notably lower than fully intercalated graphite. Combining the experimental findings and DFT calculations, we show that the critical step in bilayer intercalation is a transition from AB to AA stacking which occurs at a density of ∼0.9·1014 cm−2. Our findings reveal the mechanism and limits for electrochemical intercalation of bilayer graphene and suggest possible avenues for increasing the Li storage capacity.

C60 Fullerene-Reinforced Silicon Oxycarbide Composite Fiber Mats: Performance as Li-Ion Battery Electrodes.

Precursor-derived silicon oxycarbide (SiOC) has emerged as a potential high-capacity anode material for rechargeable Li-ion batteries. The polymer processing and pyrolysis route, a hallmark of polymer-derived ceramics, allows chemical interfacing with a variety of nanoprecursors and nanofiller phases to produce composites with low-dimensional structures such as fibers and coatings not readily attained in traditional sintered ceramics. Here, buckminsterfullerene or C60 was introduced as a filler phase in a hybrid precursor of 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasiloxane (TTCS) along with polyvinylpyrrolidone or PVP as a spinning agent to fabricate electrospun fiber mats, which upon a high-heat treatment transformed to a C60-reinforced SiOC ceramic composite. Tested as the self-supporting working electrode in a Li-ion half-cell, C60-reinforced fiber mats show a much-improved reversible capacity (825 mA h g-1), nearly 100% Coulombic efficiency, and superior rate capability with low-capacity decay at high currents (only 25.5% decay at 800 mA g-1) compared to neat C60 and neat carbonized fiber electrodes.

In-Situ and in-Operando Li-Ion Batteries for Materials Science Education

Electrochemical energy storage systems, particularly Li-ion rechargeable batteries (LiRB), have a key role to play in fortifying US energy generation, decarbonizing the electricity sector, and limiting anthropogenic climate change. LiRBs suffer from limited lifetimes, insufficient energy densities, and fire risks, which are all materials science and engineering challenges stemming from various irreversible degradation processes occurring at nano and micro-scales. These batteries function via the reversible diffusion of Li ions from a Li-rich cathode to a Li-poor anode, each of which undergo various levels of volumetric phase changes, plastic deformation, and microcracking with each charging cycle, thereby compromising subsequent battery performance. Therefore, it is imperative to understand the nano-mechanical processes associated with LiRB degradation and predict transformative material designs that can lead to manufacturing cheaper, denser, and safer LiRBs. Such understanding and design would be instrumental to achieving the US 2050 Net Zero Goal. Additionally, the US lags 10x behind China in terms of Li battery manufacturing capability, and thus a LiRB-aware Research and Development workforce is paramount for continued US energy security. In this context, we propose a new design for in-situ and in-operando Li-ion battery research and education. This battery design will be used in a classroom/lab setting to discuss fundamental materials science concepts such as diffusion, grain-boundaries, and fracture. This activity will be used to broaden "missing millions" student participation in a crucial area of energy research at a minority serving institution.

Glassy Oxides as Positive Electrode Materials for Sustainable and High Energy Density Li-Ion and Na-Ion Batteries: First Attempts to Establish Relationships between Glass Compositions, Physicochemical Characterizations and Electrochemical Properties with Machine Learning and Design of Experiments Approaches

Today, rechargeable lithium-ion batteries (LIBs) represent one of the best alternatives to reduce our dependency on fossil fuels. LIBs are using cathode materials based on polycrystalline oxides or polyanionic compounds [1]. However, their performances can be limited by their crystalline structure when other compounds suffer from metallic dissolution and irreversible phase changes during cycling [2]. To overcome these key shortcomings, implementing glasses or glass-ceramics as cathode materials is an interesting approach [3]. Glasses have a structure composed of more free volume, and, in the literature that is mainly concerning glasses containing Vanadium transition metal, the glasses can so accept a large amount of lithium [4] and easily accommodate structural changes upon lithium ions extraction/insertion [5]. Furthermore, glass production is a scalable process and can be commercially easier to implement than most of synthesis processes of conventional cathode materials.The main objective targeted is to develop high capacity positive electrodes (up to 300mAh/g) for Li-ion batteries based on glassy oxides without critical transition metals such as Cobalt and Vanadium. The ambitious target is to exceed 1000Wh/kg at the active material level and so enable energy densities of 300-350 Wh/kg at the Li-Ion cell level. Additionally, the electrochemical behavior of some alkali-free glass compositions will be evaluated in sodium-ion configuration. The major scientific objective is to correlate the most relevant physicochemical properties of glass with the corresponding electrochemical performances using machine learning approaches or design of experiment methodology. For a better understanding of involved processes, three oxides glass families are studied as promising cathode materials for sustainable and high energy density lithium batteries. These oxides are composed of: i) a glass network-forming element (Si, B, P) leading to the 3 different families, ii) a transition metal (Mn, Fe, ...) and optionally iii) an alkali (Li, Na).The influence of the nature of the transition metal and the polyanionic group corresponding to the network-forming element (PO4, BO3, SiO4) on the electrical properties of the as-prepared glasses measured at different temperatures will be presented mainly for the lithiated compounds. For microstructural characterization, several techniques were coupled such as X-Ray Diffraction (XRD), SEM-EDX, DTA/TGA, Raman, IR and UV-Vis spectroscopies, Electrochemical Impedance Spectroscopy (EIS) and chronoamperometry.Finally, the electrochemical properties in terms of specific capacity, redox potentials, first cycle capacity loss, coulombic and energetic efficiencies of these materials were investigated in coin-cells vs lithium (or sodium) metal electrode. To understand the electrochemical processes involved in these materials at room temperature, SEM-EDX, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Mossbauër Spectroscopy for iron based compounds were coupled and performed on the as-prepared glasses and on ex-situ (after cycling) materials at different electrochemical states of charge.All the generated data and measurements were analyzed by machine learning approach and tools and in some cases compared with a more classical Design of Experiments (DOE) approach. For instance, figure 1 illustrates the contour diagram of first discharge capacities in the mixture diagram of phosphate glasses based on 3 different transition metal oxides. The final goal is to establish more precisely the relationships between the different glassy oxides structures and their electrochemical performances. First results of this important work of elaboration, characterization and data analysis will be presented here. This new study will bring significant elements to optimize both the glass composition and its elaboration conditions to obtain high performance cathode materials without critical materials.[1] Nitta, N. et al., Li-ion battery materials: present and future. Materials Today 18, 252–264 (2015).[2] Tesfamhret, Y. et al., On the Manganese Dissolution Process from LiMn2O4 Cathode Materials. ChemElectroChem 8, 1516–1523 (2021).[3] K. Kercher et al., « Mixed polyanion glass cathodes: Glass-state conversion reactions », J. Electrochem. Soc., vol. 163, no 2, p. A131-A137, 2016, doi: 10.1149/2.0381602jes [4] Afyon, S. et al., New High Capacity Cathode Materials for Rechargeable Li-ion Batteries. Scientific Reports 4, 7113 (2015).[5] Kindle, M. et al., Alternatives to Cobalt. ACS Sustainable Chemistry Engineering 9, 629–638 (2021). Figure 1

Charge-Sharing Based Stabilization of Nano-Porous Organic Electrode for Rechargeable Li-Ion Battery

Organic-based lithium-ion batteries have garnered increasing attention due to their potential for cost-effectiveness, sustainability, and high energy density. Despite the promising theoretical prediction, the actual battery performance of organic-based electrodes has frequently fallen below the expected values. This discrepancy is primarily attributed to a low density of active sites, limited ion diffusivity, and high solubility to the electrolyte. This study introduces 5,10-dihydro-5,10-dimethylphenazine (DMPZ) as an organic active material, demonstrating superior electrochemical performance characterized by high capacity and prolonged cycle performance. To achieve a high capacity, a cryogenic milling is employed to create a porous nanostructure, enhancing the surface-to-volume ratio without altering the molecular structure. Consequently, the initial specific capacity of the porous DMPZ electrode reaches 184 mAh g-1 at 0.6 C, representing a remarkable 180% increase compared to non-milled DMPZ. To improve cycle stability, a charge-sharing reaction among organic active materials is facilitated by forming an organic nanocomposite comprising DMPZ and various n-type organic materials. The organic nanocomposite effectively mitigates the elution of organic active materials, ensuring unprecedented cycling stability with a capacity retention exceeding 90% over 500 cycles with initial specific capacity of 248 mAh g-1. C-rate tests at 1.2, 2, 4, and 8 C demonstrate outstanding rate capability, with an average capacity of 105 mAh g-1 at 8 C. The performance enhancement mechanism of the organic nanocomposite cathode is elucidated through experimental analyses, including ex-situ XPS, PiFM, and FTIR. These analyses collectively contribute to a comprehensive understanding of the mechanisms underlying the observed improvements in battery performance.

Optimizing Hard Carbon Anodes from Agricultural Biomass for Superior Lithium and Sodium Ion Battery Performance.

Biomass-derived carbon materials are gaining attention for their environmental and economic advantages in waste resource recovery, particularly for their potential as high-energy materials for alkali metal ion storage. However, ensuring the reliability of secondary battery anodes remains a significant hurdle. Here, we report Areca Catechu sheath-inner part derived carbon (referred to as ASIC) as a high-performance anode for both rechargeable Li-ion (LIBs) and Na-ion batteries (SIBs). We explore the microstructure and electrochemical performance of ASIC materials synthesized at various pyrolysis temperatures ranging from 700 to 1400 °C. ASIC-9, pyrolyzed at 900 °C, exhibits multilayer stacked sheets with the highest specific surface area, and the least lateral size and stacking height. ASIC-14, pyrolyzed at 1400 °C, demonstrates the most ordered carbon structure with the least defect concentration and the highest stacking height and an increased lateral size. ASIC-9 achieves the highest capacities (676 mAh/g at 0.134 C) and rate performance (94 mAh/g at 13.4 C) for hosting Li+ ions, while ASIC-14 exhibits superior electrochemical performance for hosting Na+ ions, maintaining a high specific capacity after 300 cycles with over 99.5 % Coulombic efficiency. This comprehensive understanding of structure-property relationships paves the way for the practical utilization of biomass-derived carbon in various battery applications.

Carbon coated Li3V2(PO4)3 derived from phytic acid with ultra-high rate performance for rechargeable Li ion batteries

The carbon coating strategy has great potential in improving the conductivity of Li3V2(PO4)3 (LVP). However, the preparation of carbon-coated LVP requires an additional carbon source and a complex synthesis process, such as the prereduction of V5+, which poses obstacles to large-scale production. In this article, the phytic acid, a kind of natural biological material with environmental benign and natural abundance, is directly chelated with V3+ and employed as both the phosphorus source and carbon source in the manufacturing procedure of LVP/C material for electrodes. The physical and electrochemical properties of LVP/C material may be tailored by carefully controlling the heat treatment temperature. This process leads to a remarkable boost in key performance metrics, including initial discharge capacity at 1 C (128.35 mAh·g-1), long cycle life at 10 C (115.75 mAh·g-1 after 1000 cycles), and rate capability at 50 C (101.83 mAh·g-1), all attributed to improved electronic conductivity and enhanced ion diffusion kinetics. The simple, novel, and energy-saving method demonstrates great potential for large-scale preparation for the high-performance cathode materials.

Lithium ionic conductivity and structural studies of NASICON structured Li0.4Sr0.3Zr0.5Ti1.5(PO4)3

Stable solid electrolytes have been the subject of intense research due to the growing demand for energy storage and portable energy sources in rechargeable Li-ion batteries. Sodium (NA) super (S) ionic (I) conductor (CON) abbreviated as NASICON are suitable for use as solid electrolytes due to their excellent ionic conductivity and chemical stability. We have reported the effect of partial doping of Sr at Li and Zr4+ at Ti4+ position on the structure and ionic conductivity of composition Li0.4Sr0.3Ti2(PO4)3 (LSTP). The composition with formula Li0.4Sr0.3Ti2−xZrx(PO4)3 (x = 0.0, 0.5, 2.0) were prepared by solid state reaction method. The phase and crystal structure were examined using X-ray diffraction (XRD) patterns. The compositions were in rhombohedral phase with the space group R 3¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\overline{3}$$\\end{document} c. The doping of Zr4+ in LSTP causes the peaks in the XRD spectra for doped composition (x = 0.5, 2.0) to move towards lower angle. The displacement of the XRD peaks towards lower angle side show the expansion in the lattice of the Zr doped compositions Li0.4Sr0.3Ti1.5Zr0.5(PO4)3 and Li0.4Sr0.3Zr2(PO4)3. The presence of stretching and bending modes of PO4 groups in the prepared compositions was identified by FTIR spectra. The enhanced bulk conductivity of 4.32 × 10–5 S/cm for Zr doped composition Li0.4Sr0.3Ti1.5Zr0.5(PO4)3 and 3.20 × 10–5 S/cm for composition Li0.4Sr0.3Zr2(PO4)3 is observed at 25 °C. The modulus peaks in the Zr doped composition Li0.4Sr0.3Ti1.5Zr0.5(PO4)3 is displaced towards higher frequencies at 450 °C, indicating the presence of the thermally produced dielectric relaxation phenomenon and charge carrier hopping. The cole cole plot consisting of one semicircle in case of Li0.4Sr0.3Ti1.5Zr0.5(PO4)3 discusses the contribution of bulk and grain boundary resistances and is fitted by equivalent circuit consisting of CPE and R element joined in parallel.

Green biomediated synthesis of anodized WO3 nanocatalysts using Melia azedarach leaves extract for the energetic transition: Solar hydrogen and Li-ion batteries

This study reports the bio-mediated synthesis of tungsten trioxide nanostructures from aqueous extracts of Melia azedarach (L.) dry leaves. The synthesis was carried out by electrochemical anodization of tungsten foils in the presence of different volume percentages of leaves extracts. These nanostructures were afterwards completely characterized by Field-Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy (HR-TEM), impedance measurements, linear sweep voltammetry in the presence of simulated solar light and UV-Vis spectroscopy. Finally, these nanoelectrodes were used as (photo)electrocatalysts in the photoelectrochemical water splitting process to obtain green hydrogen and as anodes in Li-ion rechargeable batteries. Nanostructures fabricated with 5% M. azedarach leaves extract provided the best (photo)electrocatalytic behavior for both applications, since in that biogenic electrolyte, thin nanorods arranged in very porous and spongy layers were formed. Therefore, the significant increase in specific surface area found for nanostructures fabricated following this green route, in comparison with the blank sample (i.e., nanostructure formed following a non-green route), was essential to enhance their performance as promising efficient (photo)electrocatalysts.

Heavily vanadium-doped LiFePO4 olivine as electrode material for Li-ion aqueous rechargeable batteries

Since LiFePO4 batteries play a major role in the transition to safe, more affordable and sustainable energy production, numerous strategies have been applied to modify LFP cathode, with the aim of improving its electrochemistry. In this contribution, a highly vanadium-doped LiFe0.9V0.1PO4/C composite (LFP/C-10V) is synthesized using the glycine combustion method and characterized by x-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetry Differential Thermal Analysis (TGDTA) and Cyclic Voltammetry (CV). It is shown that 10wt.% of vanadium can substitute Fe positions, thus decreasing unit cell volume, which is followed by generation of Li3V2PO4 traces, as detected by CV. High vanadium doping does not change the carbon content in the composite (≈13 wt%) but improves its electronic conductivity and electrochemical performance in both aqueous and organic electrolytes. The reversibility and current response are increasing following the trend: LFP/C, LFP/C -3mol%V, LFP/C - 5 mol % and LFP/C-10 mol %. The best specific capacity is obtained for the most highly doped olivine, which exhibits a reversible process at 1 mV s−1 in an aqueous electrolyte, thus showing a peak-to-peak distance of 56 mV. The high capacity of LFPC-10V is measured in both LiNO3 and NaNO3 electrolytes amounting to around 100 mAh g−1 at 20 mV s−1. Still, the material is only stable in LiNO3 electrolyte, making it more suitable for Li than Na-ion aqueous rechargeable batteries.

Advanced Prussian Blue Cathodes for Rechargeable Li-Ion Batteries

Taking advantage of fact that the surface electrons of metallic nanoparticles (NPs) can be effectively released even at a low voltage bias, we demonstrate an improvement in the electrochemical performance of nanosized Prussian Blue (PB)-based secondary batteries through the incorporation of bare Ag or Ni NPs in the vicinity of the working PB NPs. It is found that the capacity for electrochemical energy storage of the 17 nm PB-based battery is significantly higher than the capacity of 10 nm PB-based, 35 nm PB-based or 46 nm PB-based batteries. There is a critical PB size for the highest electrochemical energy storage efficiency. The full specific capacity CF of the 17 nm PB-based battery stabilized to 62 mAh/g after 130 charge–discharge cycles at a working current of IW = 0.03 mA. The addition of 14 mass percent of Ag NPs in the vicinity of the PB NPs gave rise to a 32% increase in the stabilized CF. A 42% increase in the stabilized CF could be obtained with the addition of 14 mass percent of Ag NPs on the working electrode of the 35 nm PB-based battery. An enhancement in CF was also found for electrodes incorporating bare Ni NPs but the effect was smaller.

A Fast-Charge Graphite Anode with a Li-Ion-Conductive, Electron/Solvent-Repelling Interface.

Graphite has been serving as the key anode material of rechargeable Li-ion batteries, yet is difficultly charged within a quarter hour while maintaining stable electrochemistry. In addition to a defective edge structure that prevents fast Li-ion entry, the high-rate performance of graphite could be hampered by co-intercalation and parasitic reduction of solvent molecules at anode/electrolyte interface. Conventional surface modification by pitch-derived carbon barely isolates the solvent and electrons, and usually lead to inadequate rate capability to meet practical fast-charge requirements. Here we show that, by applying a MoOx-MoNx layer onto graphite surface, the interface allows fast Li-ion diffusion yet blocks solvent access and electron leakage. By regulating interfacial mass and charge transfer, the modified graphite anode delivers a reversible capacity of 340.3 mAh g-1 after 4000 cycles at 6 C, showing promises in building 10-min-rechargeable batteries with a long operation life.

Design, Testing, Evaluation, and Implementation of an Arduino-based Mosquito-Repellent System

Aims: The primary objective of this research drive is to design, develop, and evaluate an Arduino-based mosquito-repellent system. This work underscores the importance of developing sustainable and eco-friendly solutions for mosquito control.&#x0D; Study Design: An Arduino microcontroller board is used, and an assembly language program is developed to repel mosquitoes from the surroundings. This system uses piezoelectric disks, LED lights, LCD monitor along with the Arduino board and produces ultrasonic sound to protect humans and the environment from mosquitoes.&#x0D; Place and Duration of Study: The research effort was steered by the authors in a group under the supervisor of a faculty member as a part of the course capstone project work of the Bachelor of Science in Engineering degree in Computer Science and Engineering at the American International University Bangladesh (AIUB), Dhaka, Bangladesh. The authors performed their research tasks at AIUB from May 2023 to January 2024.&#x0D; Methodology: The innovative mosquito-repellent system uses an Arduino Mega 2560 microcontroller to generate a cutting-edge solution to tackle the problem of mosquito infestations. The system can produce an electric signal that can emit mechanical ultrasound signals to be harnessed using a series-connected eight piezo-electric discs. To power up the system, it uses four Li-ion rechargeable batteries charged by using solar energy from the home solar system. Besides, it uses LEDs to indicate the status of the repellent system.&#x0D; Results: The generated ultrasonic signal is observed on the oscilloscope screen and its’ value is exhibited on the LCD screen to evaluate the system performance. Testing confirms that the system can drive away mosquitoes within its 3 m surroundings in 2-3 minutes. Besides, the system parameter and cost comparison show that this scheme suggests a worthwhile and sustainable result for making a mosquito-free environment.&#x0D; Conclusion: The development of a mosquito-repellent system using ultrasonic sound waves based on an Arduino microcontroller offers a sustainable and effective alternative to traditional methods of mosquito control. Since the system is chemical and health-hazard-free, it is eco-friendly and makes human life more comfortable. The system is portable and cost-effective, making it suitable for use in various settings.

Recovery of isolated lithium through discharged state calendar ageing.

Rechargeable Li-metal batteries have the potential to more than double the specific energy of the state-of-the-art rechargeable Li-ion batteries, making Li-metal batteries a prime candidate for next-generation high-energy battery technology1-3. However, current Li-metal batteries suffer from fast cycle degradation compared with their Li-ion battery counterparts2,3, preventing their practical adoption. A main contributor to capacity degradation is the disconnection of Li from the electrochemical circuit, forming isolated Li4-8. Calendar ageing studies have shown that resting in the charged state promotes further reaction of active Li with the surrounding electrolyte9-12. Here we discover that calendar ageing in the discharged state improves capacity retention through isolated Li recovery, which is in contrast with the well-known phenomenon of capacity degradation observed during the charged state calendar ageing. Inactive capacity recovery is verified through observation of Coulombic efficiency greater than 100% on both Li||Cu half-cells and anode-free cells using a hybrid continuous-resting cycling protocol and with titration gas chromatography. An operando optical setup further confirms excess isolated Li reactivation as the predominant contributor to the increased capacity recovery. These insights into a previously unknown pathway for capacity recovery through discharged state resting emphasize the marked impact of cycling strategies on Li-metal battery performance.

N-doped lithium titanium oxide for high power Li-ion rechargeable batteries with excellent cyclability

Lithium titanate, Li4Ti5O12 (LTO) is being explored as an anode in Li-ion batteries owing to its minimal structural change during lithiation/delithiation and excellent capacity retention at higher current rates. However, the lack of stable cyclability at higher applied currents owing to low electronic conductivity, restricts its widespread applications. Solid state anionic doping represents a convenient strategy to improve the intrinsic electronic conductivity of the LTO material. Hence, a facile and scalable solid state‐inspired protocol has primarily been devised aimingthe large-scale production of nitrogen-doped LTO. The structural analysis demonstrates the diffusion of nitrogen into the lattice without damaging the intrinsic microstructure of LTO. The 2% nitrogen-doped LTO as a working electrode in Li-ion half-cell, displays enhancement in Li-storage capacity by 30%. Moreover, it exhibits excellent rate performance (131 mAhg−1 @ 5C) and ultra-long cycling stability upto 1000 cycles retaining 82 % capacity. Further, full cell study of N@LTO with LiCoO2 exhibits specific capacities of more than 155 mAh/g at a 0.05C rate. Overall, the enhancement in performance attributes to N doping which is likely to improve not only the electrical conductivity but also the ion transport capabilities. Hence the N@LTO will have potential in high power Li-ion batteries.

Challenges and opportunities using Ni-rich layered oxide cathodes in Li-ion rechargeable batteries: the case of nickel cobalt manganese oxides

Doping, coating, surface modification, formation of composites and control of crystalline orientation can control the capacity retention of Ni-rich cathodes. Furthermore, the design of Co-free Ni-rich cathodes may provide a cost-effective solution.