Rechargeable Li-ion Batteries Research Articles

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.
 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.
 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.
 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.
 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.
 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.

Investigating the Reaction Mechanism of Vinylene Carbonate Additive in Lithium Ion Batteries Using X-Ray Photoelectron Spectroscopy

The rechargeable Li-ion battery is an enabling technology which facilitates the electrification of the automotive industry and reduces the demand for fossil fuels. During the charge and discharge of a battery, a solid-electrolyte interphase (SEI) forms between the liquid electrolyte and the solid negative electrode as a result of electrolyte degradation. The chemical and physical stability and the functionality of the SEI is a key determining factor of battery performance. The chemical composition of the SEI is mainly controlled by the choice of solvent and salt used, but can be manipulated by the addition of electrolyte additives that influence the electrolyte degradation process.Vinylene carbonate (VC) is an additive used in many commercial Li-ion battery configurations. The addition of a small amount of VC to ethylene carbonate (EC) containing electrolytes has been demonstrated to drastically improve several performance metrics for batteries including cycle life, coulombic efficiencies, capacity retention and thermal stability. The success of VC is widely attributed to its ability to form a thinner, denser and more robust SEI, which better protects the electrode surface and prevents further electrolyte consumption. This improvement in stability has been linked to the presence of poly(VC) in the SEI, but the mechanism by which VC reacts in EC-containing electrolytes is still an area of ongoing study. Whilst computational methods have suggested several potential decomposition pathways of electrolytes containing VC, it is yet to be convincingly demonstrated experimentally. Whilst there is a general consensus about ‘What?’ forms in the SEI on the addition of VC to EC-containing solvent, this work aims to confirm ‘Where?’ these components are in the interface and the currently unanswered questions of ‘How?’ and ‘Why?’ they form.Using highly surface sensitive photoelectron spectroscopy (PES) measurements of the SEI deposited at various potentials, we identify the differences in composition and structure that result from the addition of VC additive to EC-containing electrolytes. The SEI formation is studied using a smooth Au surface as the model working electrode and a fluorine free EC:diethyl carbonate (DEC) (1:9) 1 M LiClO4 electrolyte in an attempt to isolate the impact of VC on the SEI. A potential step procedure allows analysis of the working electrode surface by PES at several progressively more negative potentials on the first charge. Through systematic variation of components such as the concentration of VC, the ratio of EC:DEC and swapping Au for other electrode materials such as Cu or Si, the interaction between VC, EC and the electrode surface is revealed. The differences in SEI composition and structure formed in each environment and at each potential step are correlated to quartz crystal microbalance (QCM) data in order to identify potential reaction mechanisms and formation processes. The results play a key role in understanding the reaction pathway of VC-containing electrolytes and will accelerate development of more efficient electrolyte additives.

Bio-Waste Derived Hard Carbon: Effect of Treatment Conditions on Electrochemical Performance

There is a great deal of demand for rechargeable Li-ion batteries due to their high energy and power density compared to other rechargeable batteries. Despite the concern about limited lithium resources, scientists have re-examined sodium-ion batteries, since sodium is below lithium on the periodic table, and the two metals have many similar properties. As a result of its low cost, good cycle life, and reversible capacity, hard carbon (HC) is considered to be the most attractive negative electrode material for sodium-ion batteries. Nevertheless, the practical application of HC remains challenging due to its low capacity and initial Coulombic efficiency (ICE). We investigated how pre-treatment conditions affected the graphitization degree in order to overcome these issues. In addition, we observed a strong correlation between pre-oxidation and electrochemical performance when the carbonization temperature was increased. The observed results will be presented during the presentation. Acknowledgments This work was funded by the Ministry of Education and Science of the Republic of Kazakhstan Grant (AP09259165) and by Nazarbayev University under Collaborative Research Program Grant № 20122022P1611, AK.

Structural, electrical, and electrochemical studies of the olivine LiMPO4 (M=Fe, Co, Cr, Mn, V) as cathode materials for lithium-ion rechargeable batteries based on the intercalation principle

Despite significant efforts to identify other substituents, carbon remains the only economically viable negative electrode (anode) material for Li-ion batteries (LIBs). The current state of knowledge on the understanding, characterization, and improvement of carbon anode materials is reviewed. A brief history of developments in carbon host lattices is provided. The methodologies used to characterize the lithium insertion and de-insertion processes and a wide spectrum of carbon materials, from amorphous to highly oriented graphitic materials, are described. The basic studies of the electrochemical process on natural graphite and highly oriented pyrolitic graphite materials are then thoroughly examined. Following that, the issues and opportunities of several hard carbon compounds that boost battery capacity are examined. Several innovative carbon materials and carbon-based composites are also introduced. The electrochemical interaction of anode material with lithium could produce an intercalation product, which serves as the foundation for a novel battery system. Structural retention causes this reaction to proceed quickly and with a high degree of reversibility at room temperature. Titanium disulfide is one of the latest solid cathode materials. In this context, the paper presents a comprehensive theoretical comparison of the electrochemical electrical and physical properties of iron (Fe)-, cobalt (Co)-, manganese (Mn)-, chromium (Cr)-, and vanadium (V)-based LiMPO4 materials for cathode design in lithium (Li)-ion battery applications using the intercalation principle. The work highlighted many material and performance aspects of the cathode design, such as the cohesive energy of the material, Li-intercalation energy in olivine structure, and physical, electrochemical, and electrical analyses of LiMPO4 for rechargeable Li-ion batteries. We also examine the evolution of LIB technology based on the olive cathode materials, which are also evaluated.

Printable and Free-Standing Silicon-Based Anode for Current Collector-Free Lithium-Ion Batteries.

The evolution of Li-ion rechargeable batteries has driven a demand for systems exceeding the energy density and shape diversity of conventional lithium-ion batteries. Silicon (Si)-based materials, suitable for high-energy-density applications, have been restricted in practical use due to their inherent structural instability and poor conductivities upon electrochemical cycling. Here, we propose a fully printable and free-standing anode, composed of hollow SiOx/C (H-SiOx/C) composite material and an MXene conductive binder, exhibiting high specific capacity, structural reliability, and superior ionic conductivity without any current collector. The hollow structure of H-SiOx/C accommodates volume changes during cycling, while the MXene binder forms a three-dimensional interconnected conducting structure for maintaining the structural integrity of electrodes without a current collector. Furthermore, the printability and free-standing nature of the H-SiOx/C/MXene anode are validated in both coin-type full cell and heart-shaped pouch cell configurations through a straightforward stencil printing technique. This work establishes a foundation for advanced Si-based anodes, enhancing performance and design flexibility and potentially contributing to practical printable battery systems.

Synthesis of 1D/2D VO2 (B) nanowire/g-C3N4 hybrid architectures as cathode materials for high-performance Li-ion batteries

Owing to energy density, powder density, and eco-friendliness, Li-ion batteries (LIBs) are increasingly used in transportable electronic devices and electric vehicles. Monoclinic VO2 (B) has been broadly used as a cathode owing to its abundance, affordability, high capacity, and multiple oxidation states, but it's low repeatability and slow kinetics have restricted its practical applications. To mitigate these shortcomings, novel 1D/2D VO2 (B) nanowire/g-C3N4 hybrid architecture cathode materials were synthesized via hydrothermal method, and its electrochemical activity (i.e., repeatability constancy and rate capability) for LIBs was investigated. X-ray diffraction experiments confirmed that VO2 (B) exhibited a monoclinic crystal phase. SEM images revealed that the g-C3N4 and VO2 (B) presented sheet-like morphologies and comprised nanowires of uniform thickness, respectively. Electrochemical experiments revealed that the hybrid architectures showed a capacity of 779 mAh/g, and VO2 (601.4 mAh/g) and g-C3N4 (340.6 mAh/g) at 0.1 C current density. The remarkable electrochemical activity of the materials was attributed to their distinctive structures, excellent electronic conductivity associated with g-C3N4 sheets, small transport distances for Li+ ions, and fast charge transmission owing to the presence of VO2 (B) nanowires attached to g-C3N4 sheets. Consequently, distinct VO2 (B) nanowire/g-C3N4 hybrid architectures delivered suitable electrode performance to facilitate the design of high-power LIBs and these hybrid composites can serve as suitable cathode materials for rechargeable LIBs.

Boosting interfacial kinetics in extremely fast rechargeable Li-ion batteries with linear carbonate-based, LiPF6-concentrated electrolyte

Amidst the surging demand for battery-powered automobiles, it is crucial to tackle the safety risks of Li plating triggered by high cell polarization to achieve extremely fast charging (XFC) of Li-ion batteries. This study explores the impact of Li+ desolvation and solid-electrolyte interphase (SEI) chemistry on cell polarizations by utilizing linear carbonate (LC)-based, LiPF6-concentrated electrolytes (LPCEs). In the LC family, dimethyl carbonate (DMC) is thermodynamically preferred to facilitate desolvation kinetics, thereby lowering the charge-transfer barrier at the graphite anode. For effective graphite passivation and faster Li+ diffusion crossing the SEI, fluoroethylene carbonate (FEC) can help build up a thin and fluorinated SEI and reinforce the XFC cycling stability of graphite||NMC622 full cells (3.0 mAh cm−2; N/P ratio = 1.1), exhibiting 94.3% capacity retention over 500 cycles under a 10-min charging condition. The excellent XFC performance is practically validated using a 1.2-Ah pouch cell, demonstrating three times higher capacity retention over 200 cycles while suppressing Li plating-triggered cell swelling compared to conventional electrolytes. Unraveling the cell polarization governed by electrolyte chemistry provides valuable insights regarding future electrolyte designs for improving the XFC capabilities of Li-ion batteries.

Two-dimensional Ni-MOF as a high performance anode material for lithium ion batteries

Metal organic frameworks (MOFs) have attracted extensive attention as electrode materials for use in Li-ion batteries owing to their diverse structural chemistry. Herein, a new type of two-dimensional (2D) Ni-MOF is presented as a high-performance anode material for rechargeable Li-ion batteries. The layered structure endows the Ni-MOF with free channels between the inter-layers, which is beneficial to Li+ ion diffusion, making it stand out from a crowd of porous 3D molecular materials. Strikingly, when tested at 100 mA g−1, Ni-MOF demonstrates a high capacity of 765 mA h g−1. The anode material also delivers superior rate performance and good cyclability. After being charged/discharged to high rates of 2 A/g, the anode could restore its initial capability at 100 mA g−1.

Studying the Role of Additives in Carbonate Electrolytes for Graphite||NMC811 Batteries with Interface-Sensitive X-Ray Spectroscopies

Li-ion rechargeable batteries are increasingly used as power sources for portable consumer products and electric vehicles. The formation of stable electrode-electrolyte interphases is critical to long-term performance, however, these typically degrade during extended cycling due to ongoing side reactions and electrode cross-talk. Over the past few years, various electrolyte additives have been reported as being able to improve the properties of the interphases formed on electrode surfaces and suppress cell degradation. However, these are often tuned for a specific electrode (e.g. cathode), and may negatively impact on the other electrode (e.g. anode). A key experimental challenge is therefore to reveal how additives affect the interfacial layers formed at both anode and cathode in full cells, their resulting influence on the cross-talk, and on the long-term stability of each electrode. Soft X-ray absorption spectroscopy (soft-XAS) and X-ray photoelectron spectroscopy (XPS) are powerful techniques to investigate the evolution of the short-range local structure and chemical species in complex systems. These properties make soft-XAS and XPS a suitable technique to study phase evolution, chemical species, local structure and stability of the interface formed on the electrodes. Here, we have studied carbonate-based electrolytes with various additives (such as Vinylene Carbonate, Lithium difluorophosphate, and fluoroethylene carbonate) in Graphite||NMC811 full cell. Soft-XAS and XPS have been performed to understand how additives in the electrolyte alter the chemical nature of interface formed on both anode and cathode in early cycles and their influence on extended longer-term degradation related to cross-talk, such as transition metal cross-over. Further, we identified which additives are beneficial for which electrodes and which cross-talk reactions they help to mitigate, this informs the development of electrolyte formulations where different additives are combined to improve battery lifetime and performance. Comparing the chemical information obtained with electrochemical cycling data we determined the connection between the chemical degradation of the electrodes and the reduction in electrochemical performance.

Simple and Scalable Synthesis Method of γ-NaTiOPO4 for Sodium Ion Batteries in Aqueous and Non-Aqueous Electrolytes

Lithium-ion batteries have been considered a suitable battery technology for energy storage systems. However, its scarcity and high cost pose challenges to the availability of lithium for mass adoption in large applications such as energy storage. Due to their natural abundance and economic feasibility, sodium-ion batteries (SIBs) have proven to be a promising alternative for large-scale applications.1 Most anode materials for research on SIBs have focused on carbonaceous materials, oxides and polyanionic compounds of the anode, like that of lithium-ion battery research on anode materials Polyanionic compounds, especially phosphates, are of particular interest due to their structural, thermal properties and, more importantly, for avoiding undesirable sodium plating.2 Contrary to lithium counterparts, SIBs have fewer alternatives for safe anode materials applicable for both non-aqueous and aqueous rechargeable SIBs.3 Various NaTiOPO4 polymorphs have previously been reported, and these materials required a synthesis process that was extremely time-consuming and a highly pressured synthesis atmosphere. However, the methods reported still produced very small amounts of synthesized material.4-8 Due to these limitations, only the β-NaTiOPO4 phase among polymorphs was studied as an anode for SIBs in a non-aqueous electrolyte.7-8 In this study, we first report a simple and scalable solid-state synthesis method for γ-NaTiOPO4, which incorporates a high-temperature quenching process to stabilize metastable γ-NaTiOPO4 with stability. It is a promising anode for SIBs in non-aqueous and aqueous electrolytes, with a capacity of roughly 120mAh/g, voltages of 1.7V and 1.5V vs Na/Na +, and a Coulombic efficiency of up to 99.9% for up to 500 cycles at 0.5C in non-aqueous electrolyte and excellent capacity retention in a full cell of NaMn0.44O2//γ-NaTiOPO4 for up to 175 cycles in aqueous electrolyte.9 El Kharbachi, A.; Zavorotynska, O.; Latroche, M.; Cuevas, F.; Yartys, V.; Fichtner, M., Exploits, advances and challenges benefiting beyond Li-ion battery technologies. Journal of Alloys and Compounds 2020, 817.N. Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Research development on sodium-ion batteries, Chem. Rev. 114 (23) (2014) 11636–11682. H. Kim, J. Hong, K.Y. Park, H. Kim, S.W. Kim, K. Kang, Aqueous rechargeable Li and Na ion batteries, Chem. Rev. 114 (23) (2014) 11788–11827. Stus, N. V.; Slobodyanik, M. S.; Straitiychuk, D. A.; Lisnyak, V. V., Pressure induced gamma ->alpha-NaTiOPO4 phase transition. J Alloy Compd 2005, 393 (1-2), 66-69.Dahaoui, S.; Hansen, N. K.; Protas, J.; Krane, H.-G.; Fischer, K.; Marnier, G., Electric properties of KTiOPO4 and NaTiOPO4 from temperature-dependent X-ray diffraction. Journal of Applied Crystallography 1999, 32 (1), 1-10.Loiacono, G. M.; Loiacono, D. N.; Stolzenberger, R. A., Growth and properties of crystals in the system KTiOPO4-NaTiOPO4. Journal of Crystal Growth 1994, 144 (3), 223-228.Mu, L. Q.; Ben, L. B.; Hu, Y. S.; Li, H.; Chen, L. Q.; Huang, X. J., Novel 1.5 V anode materials, ATiOPO(4) (A = NH4, K, Na), for room -temperature sodium-ion batteries. Journal Jiang, L. W.; Liu, L. L.; Yue, J. M.; Zhang, Q. Q.; Zhou, A. X.; Borodin, O.; Suo, L. M.; Li, H.; Chen, L. Q.; Xu, K.; Hu, Y. S., High-Voltage Aqueous Na-Ion Battery Enabled by Inert-Cation-Assisted Water-in-Salt Electrolyte. Advanced Materials 2020, 32 (2).Kim, D.; Park, H.; Avdeev, M. ; Kim, M. ; Kang, B. (2022). Newly developed γ – NaTiOPO4 by Simple Solid-State Synthesis for Anode Material of Na-ion Batteries in Both Non-aqueous and Aqueous electrolyte. Journal of Power Sources 2022, 541 (1)

Machine learning force fields for molecular liquids: Ethylene Carbonate/Ethyl Methyl Carbonate binary solvent

Highly accurate ab initio molecular dynamics (MD) methods are the gold standard for studying molecular mechanisms in the condensed phase, however, they are too expensive to capture many key properties that converge slowly with respect to simulation length and time scales. Machine learning (ML) approaches which reach the accuracy of ab initio simulation, and which are, at the same time, sufficiently affordable hold the key to bridging this gap. In this work we present a robust ML potential for the EC:EMC binary solvent, a key component of liquid electrolytes in rechargeable Li-ion batteries. We identify the necessary ingredients needed to successfully model this liquid mixture of organic molecules. In particular, we address the challenge posed by the separation of scale between intra- and inter-molecular interactions, which is a general issue in all condensed phase molecular systems.

Recent Progress in Design Principles of Covalent Organic Frameworks for Rechargeable Metal-Ion Batteries.

Covalent organic frameworks (COFs) are acknowledged as a new generation of crystalline organic materials and have garnered tremendous attention owing to their unique advantages of structural tunability, frameworks diversity, functional versatility, and diverse applications in drug delivery, adsorption/separation, catalysis, optoelectronics, and sensing, etc. Recently, COFs is proven to be promising candidates for electrochemical energy storage materials. Their chemical compositions and structures can be precisely tuned and functionalized at the molecular level, allowing a comprehensive understanding of COFs that helps to make full use of their features and addresses the inherent drawback based on the components and functions of the devices. In this review, the working mechanisms and the distinguishing advantages of COFs as electrodes for rechargeable Li-ion batteries are discussed in detail. Especially, principles and strategies for the rational design of COFs as advanced electrode materials in Li-ion batteries are systematically summarized. Finally, this review is structured to cover recent explorations and applications of COF electrode materials in other rechargeable metal-ion batteries.

Improving electrochemical performance of LiNi0.8Co0.1Mn0.1O2 cathode via polyanionic TiP2O7 coating

Safety issues of common rechargeable Li-ion batteries (LIB) necessitate urgent development of alternative high-performance electrode materials. Lithiated nickel-rich oxides (LiNi1-x-yMnxCoyO2) are promising LIB cathode materials, but they suffer from structural instabilities causing major capacity loss. To address this issue, here we use a robust ethanol-based wet coating process to coat a LiNi0.8Co0.1Mn0.1O2 LIB cathode material with polyanionic compound TiP2O7. The coating layer does not affect the phase structure of LiNi0.8Co0.1Mn0.1O2 and ensures a remarkable electrochemical performance, evidenced by the high initial Coulombic efficiency, durable cyclic stability, and excellent rate performance. The mechanisms leading to the achieved improvements are related to the effects of the coating layer which improved the Li+ diffusion capability and the electrochemical polarization. The TiP2O7 layer protects the electrode from the electrolyte by suppressing side reactions such as HF acidic attack and the associated dissolution of transition metal ion. Moreover, the unique three-dimensional (XOn)m- framework of the TiP2O7 polyanion provides plentiful accommodation sites and channels for the Li-ions diffusion. The demonstrated approach opens new avenues for practical applications of electrochemically active coatings in diverse energy storage devices and systems.

MOF-derived porous NiCo2O4 nanofile arrays as an efficient anode material for rechargeable Li-ion batteries

Due to their vast surface area and superior porosity structure, metal-organic frameworks (MOFs) derived materials have recently presented a significant promise for better lithium-ion batteries (LIBs). Herein, we synthesised MOF-derived porous NiCo2O4 nanofile arrays from a simple solvothermal technique followed by calcination at 450 °C. The prepared sample was characterized by X-ray diffraction, thermogravimetric, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller. The acquired nanofile array morphology achieved a large specific surface area of 189 m2/g can shorten the Li ions (Li+) transport and enhance the electrochemical performance. As expected, the prepared electrode reveals a discharge-specific capacity of around 1120 mAh/g at a 0.1 C rate. At 2 C rate, the electrode's specific capacity can still reach 210 mAh/g after 100 cycles. The pseudocapacitive nature of NiCo2O4 was determined by kinetic analysis, revealing the diffusion-controlled faradaic behaviour. Our prepared electrode material is considered an attractive option for the anode material in rechargeable Li-ion batteries because it has been proven to have a relatively good specific capacity and cycling stability.

COF-based anode material for rechargeable Li-ion batteries

Motivated by the synthesis of a covalent organic framework by condensation procedure of phenyl diboronic acid (denoted as COF-1), and the other theoretical studies of an energetically favorable (BO)18C36H24 unit cell, we investigate its potential as an anode material in the Li-ion battery (LIB). Using density functional theory method, we found that the COF-1 is a promising anode whose specific capacity of 513.98 mAhg-1 is higher than that of graphite, ψ-graphene and boron nanolayers (∼370 mAhg-1). Furthermore, energy diffusion barrier of Li-ions and the average voltage along the COF-1 anode are 0.34 eV and 0.85 V, respectively, which can deliver high operating voltage when linked to the cathode. These findings can pave the route for application of COFs with promising performance as the LIB anode.

Phenanthrenequinone-Based Linear Polymers as Sustainable Cathode Materials for Rechargeable Li-Ion Batteries

Phenanthrenequinone-Based Linear Polymers as Sustainable Cathode Materials for Rechargeable Li-Ion Batteries

Free-standing N-doped hollow carbon fiber encapsulate P/GeP hybrid anode for rechargeable Li-ion battery

Red phosphorus (RP) with appropriate working voltage and high lithium storage specific capacity has been considered as high-performance anode for Li-ion battery (LiB). However, the volume expansion of the RP anode reached 350 % during the intercalation/deintercalation of Li-ion processes, resulting in the detachment of active material and poor specific capacity. Herein, flexible hollow nanochannel carbon nanofiber was prepared through simple electrospinning, then P/GeP nano powder were encapsulated in the N-rich carbon nanofiber using a facile in situ synthesis method, where the introduction of GeP not only innovatively served as the high conductive dispersant for P, but simultaneously acted as the active component in reacting with Li-ion. The unique designed nanoarchitecture not only boosted the structural stability and electronic conductivity of the hybrid composite, but also facilitated the transport of electrons and Li-ion. Upon served as free-standing LiB anode, the N-doped hollow carbon fiber encapsulate P/GeP (P/GeP/C) anode displayed remarkably reversible capacities, superior rate performances, and long-term cycle stability for lithium storage. For instance, P/GeP/C of only 10.6 wt% GeP and 28.5 wt% P delivered 290.2 mA h g−1 under a high current density of 5 A g−1 and showed a high capacity of 575.6 and 436.9 mA h g−1 at a current density of 0.1 A g−1 and 1.0 A g−1 after 50 cycles, respectively.