Li-ion Batteries Research Articles

Experimental Investigations into a Hybrid Energy Storage System Using Directly Connected Lead-Acid and Li-Ion Batteries

This paper presents experimental investigations into a hybrid energy storage system comprising directly parallel connected lead-acid and lithium batteries. This is achieved by the charge and discharge cycling of five hybrid battery configurations at rates of 0.2–1C, with a 10–50% depth of discharge (DoD) at 24 V and one at 48 V. The resulting data include the overall round-trip efficiency, transient currents, energy transfers between the strings, and the amount of energy discharged by each string across all systems. The general observation is that the round-trip efficiency drops from a maximum of around 94–95% in the first stages of the charge/discharge process, when only the Li-ion strings are active, to around 82–90% when the lead-acid strings reach a DoD of up to 50%. The most important parameters in the round-trip efficiency function are the ratio between the Li-ion and lead-acid energy available and the charge/discharge current. The energy transfer between the strings, caused by the transient currents, is negligible in the first stages of the discharge and then grows, with the DoD peaking at around 60% DoD. Finally, during the first stage of discharge, when only the Li-ion strings are active, the amount of energy discharged varies with the discharge C rate, decreasing to almost half at between 0.2 and 1C.

Preparation of doped spinel LiMn2O4 cathode using α- MnO2 for high-performance Li-ion batteries

Preparation of doped spinel LiMn2O4 cathode using α- MnO2 for high-performance Li-ion batteries

Li3V2(PO4)3 sintering atmosphere optimisation for its integration in all-solid-state batteries

Integration of active materials into the architecture of all-solid-state batteries represents a significant scientific inquiry. Li3V2(PO4)3 (LVP), a positive and negative electrode active material for Li-ion batteries, has been subject to extensive research to elucidate its electrochemical behaviour during cycling processes. However, the comprehensive analysis of its thermal behaviour under different sintering atmosphere conditions has remained underexplored, particularly in the context of its compatibility with solid electrolytes. This study presents a meticulous study of sintering process under different atmospheres with precise control over oxygen partial pressure. Interestingly, we were able to sinter LVP and obtain dense, pure ceramic phase under slightly oxidising atmosphere, characterized by conductivity properties analogous to those observed in samples sintered under Ar/H2 conditions. The findings of this investigation contribute to the understanding of the optimal conditions required for the sintering of LVP, paving the way for the co-sintering of this material with inorganic solid electrolyte unstable under reducing atmosphere, such as LATP.

Theoretical designing of Ni-doped PtSTe monolayer as a promising gas sensor upon thermal runaway gases in the Li-ion battery

This study proposes Ni-doped Janus PtSTe (Ni-PtSTe) as a novel sensing material for detecting three critical gases (CO, CO2, and C2H4), with potential applications in gas sensors and Li-ion battery monitoring. The Ni-doping favors the Te surface of the PtSTe monolayer, with a formation energy of -1.19 eV. The adsorption capacity follows the order: CO > C2H4 > CO2, with chemisorption in CO and C2H4 systems and physisorption in CO2 system. The analysis of electronic properties in gas adsorbed Ni-PtSTe systems indicate a reduced bandgap in CO and C2H4 systems, resulting in the sensing response of 99.25% and 97.71%, respectively. The work function increases significantly in the presence of CO and C2H4, suggesting its suitability as a work function-based sensor. These results highlight the promising sensing capabilities of Ni-PtSTe monolayer, expanding the horizon for PtSTe-based materials and inspiring cutting-edge research.

A Novel Spotted Hyena Optimizer for the Estimation of Equivalent Circuit Model Parameters in Li-Ion Batteries

Li-ion batteries possess significant advantages like large energy density, fast recharge, and high reliability; hence, they are widely adopted in electric vehicles, portable electronics, and military and aerospace applications. Albeit having their merits, accurate battery modeling is subjected to problems like prior information on internal chemical reactions, complexity in problem formulation, a large number of unknown parameters, and the need for extensive experimentation. Hence, this article presents a reliable Spotted Hyena Optimizer (SHO) to determine the equivalent circuit parameters of lithium-ion (Li-ion) batteries. The methodology of the SHO is derived from the living and hunting tactics of spotted hyenas, and it is efficiently applied to solve the battery parameter estimation problem. Nine unknown battery model parameters of a Samsung INR 18650-25R are determined using this method. The model parameters estimated are endorsed for five different datasets with various discharge current values. Further, the effect of parameter range and its selection is also emphasized. Secondly, for validation, various performance metrics such as Integral Squared Error, mean best, mean worst, and Standard Deviation are evaluated to authenticate the superiority of the proposed parameter extraction. From the computed results, the SHO algorithm is able to explore the search area up to 89% in the case of larger search ranges. The chosen model and range of the SHO precisely predict the behavior of the proposed Li-ion battery, and the results are in accordance with the catalog data.

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.

Artificially regulated interphase on natural graphite realizes rapid charge and durable high-temperature cycling of Li-ion batteries

Natural graphite (NG) is a strong competitor in the anode market of Li-ion batteries because of its low cost, rich resource, low energy consumption and low carbon dioxide emission during production. The main problems inhibiting its universal application are its high surface area and the attendant unstable solid/electrolyte interphase (SEI), leading to unsatisfactory cycling and rate performance. In this work, a Li+-conductive, thermally and mechanically stable organic polymer layer is successfully constructed on NG surface by virtue of the simultaneous polymerization and crosslinking reactions of chitosan (CS) and acrylic acid (AA). With controllable thickness, the polymer layer denoted as CSAA significantly decreases the specific surface area of NG, works as an inner SEI substrate greatly mitigating the decomposition of electrolyte, and induces the formation of a LiF-rich SEI outer layer. The SEI resistance and activation energy for charge-transfer reactions are considerably reduced. Benefiting from the superior properties of CSAA-derived SEI, the NG@CSAA anodes exhibit a high initial coulombic efficiency of 94.1 %, fast charge/discharge capability and prolonged cycle life at both 25 °C and 45 °C in the LiFePO4 cathodes-based full cells.

Quantifying the Aging of Lithium-Ion Pouch Cells Using Pressure Sensors

Understanding the behavior of pressure increases in lithium-ion (Li-ion) cells is essential for prolonging the lifespan of Li-ion battery cells and minimizing the safety risks associated with cell aging. This work investigates the effects of C-rates and temperature on pressure behavior in commercial lithium cobalt oxide (LCO)/graphite pouch cells. The battery is volumetrically constrained, and the mechanical pressure response is measured using a force gauge as the battery is cycled. The effect of the C-rate (1C, 2C, and 3C) and ambient temperature (10 °C, 25 °C, and 40 °C) on the increase in battery pressure is investigated. By analyzing the change in the minimum, maximum, and pressure difference per cycle, we identify and discuss the effects of different factors (i.e., SEI layer damage, electrolyte decomposition, lithium plating) on the pressure behavior. Operating at high C-rates or low temperatures rapidly increases the residual pressure as the battery is cycled. The results suggest that lithium plating is predominantly responsible for battery expansion and pressure increase during the cycle aging of Li-ion cells rather than electrolyte decomposition. Electrochemical impedance spectroscopy (EIS) measurements can support our conclusions. Postmortem analysis of the aged cells was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to confirm the occurrence of lithium plating and film growth on the anodes of the aged cells. This study demonstrates that pressure measurements can provide insights into the aging mechanisms of Li-ion batteries and can be used as a reliable predictor of battery degradation.

Battery Thermal Management System in Electric Two-Wheelers

This work documents the design of a battery thermal management system for an electric vehicle in which a liquid cooling system was designed for a 24V Li-ion battery pack. Then, a thermal simulation was performed by using one-dimensional heat transfer modelling using Solidworks. This model also consists of the design of a heater, pump and evaporator to determine the total energy consumption of BTMS. The results indicate that the battery temperature is maintained between 20-30 °???? for various driving profiles with a maximum energy consumption of 0.3%.This work documents the design of a battery thermal management system for an electric vehicle in which a liquid cooling system was designed for a 24V Li-ion battery pack. Then, a thermal simulation was performed by using one-dimensional heat transfer modelling using Solidworks. This model also consists of the design of a heater, pump and evaporator to determine the total energy consumption of BTMS. The results indicate that the battery temperature is maintained between 20-30 °???? for various driving profiles with a maximum energy consumption of 0.3%.

Understanding the role played by Cu nanoparticles embedded in situ in a carbonaceous matrix as sulfur host for lithium-sulfur batteries

The lithium-sulfur (Li-S) battery is a promising alternative to Li-ion batteries as an energy storage system, owing to its higher capacity and specific energy values. To tackle its intrinsic problems, the element copper (Cu) is an attractive option given both its excellent conductivity and its ability to interact with highly reactive polysulfides. Here, we propose the use of a carbon/copper composite (90.5:9.5 wt ratio) obtained by thermal decomposition of a single precursor based on a Cu(II) oleate/oleic acid complex and eliminating the use of H2 as a reducing agent as commonly reported. Cu nanoparticles (mean particle size around 15 nm in diameter) which are highly dispersed on an amorphous carbon matrix derived from an organic framework, enhance both the conductivity and the ability for the chemical adsorption of lithium polysulfides (LiPSs), and thus increasing the reaction efficiency. Poor cycling stability, less specific capacity, and diminished rate capability were observed when the Cu content was reduced to around 70 % through treatment with concentrated nitric acid. This confirms the electrocatalytic role of the metal.

Computational screening of sodium solid electrolytes through unsupervised learning

All-solid-state Na-ion batteries have emerged as alternatives to all-solid-state Li-ion batteries owing to the global abundance of Na element. However, finding a commercially viable Na-ion solid-state electrolyte (SSE) remains challenging due to the relatively poor understanding of the structures effective for conduction compared to those for Li-ion SSE. In this study, we develop a screening framework based on an unsupervised machine learning technique to characterize Na-ion SSEs according to their lattice structures. Specifically, we evaluate feature vectors encoding 180 structural properties for 12,670 materials containing Na ions. Subsequently, the resulting feature vectors are clustered using hierarchical density-based spatial clustering of applications with noise (HDBSCAN), leading to the discovery of 12 groups including those with experimentally proven Na-ion superionic conductors such as NASICONs and sodium chalcogenides. Post hoc analysis of these clusters reveals that the groups with high conductivity share similar characteristics, including the existence of ion channels for Na ions and the weak interactions between Na ions and the proximate atoms. Ab initio molecular dynamics simulations confirm that the promising groups exhibit exceptional ion diffusivity compared to other groups. By employing decision tree classifiers trained to screen promising groups, we demonstrate the rapid assessment of the potential of a given material. Finally, we offer perspectives and insights for the development of novel Na-ion SSEs for all-solid-state Na-ion batteries.

An Evaluation Modeling Study of Thermal Runaway in Li-Ion Batteries Based on Operation Environments in an Energy Storage System

According to the green growth and carbon-neutral policy in Korea, the installation of large-capacity ESSs is rapidly being increased, but a total number of 50 ESS fire cases have occurred since the end of 2023. ESSs are typically composed of series-parallel connections with numerous Li-ion batteries, and when the temperature of a deteriorated cell increases due to thermal, electrical, and mechanical stress, thermal runaway can occur due to additional heat generated by an internal chemical reaction. Here, an internal chemical reaction in a Li-ion battery results in the different characteristics on the decomposition reaction and heat release depending on the operation conditions in the ESS, such as the rising temperature rate, convective heat transfer coefficient, and C-rate of charging and discharging. Therefore, this paper presents mathematical equations and modeling of thermal runaway, composed of the heating device section, heat release section by chemical reaction, chemical reaction section at the SEI layer, chemical reaction section between the negative and positive electrodes and solvents, and chemical reaction section at the electrolyte by itself, based on MATLAB/SIMULINK (2022), which were validated by a thermal runaway test device. From the simulation and test results based on the proposed simulation modeling and test device according to the operation conditions in ESSs, it was found that the proposed modeling is an effective and reliable tool to evaluate the processing characteristics of thermal runaway because the occurrence time intervals and maximum temperatures had almost the same values in both the test device and simulation modeling. Accordingly, it was confirmed that the rising temperature rate and the convective heat transfer coefficient were more critical in the thermal runaway than the C-rate of charging and discharging.

Enabling Fast‐Charging and High Specific Capacity of Li‐Ion Batteries with Nitrogen‐Doped Bilayer Graphdiyne: A First‐Principles Study

Carbon‐based materials are the most important anode materials for Li‐ion batteries (LIBs). To improve the electrochemical performance of LIBs for high energy density and fast charging, advanced carbon allotropes are in the research focus. In this work, we applied the density functional theory to investigate the atomic and electronic structures as well as high Li‐ion specific capacity of graphdiyne (GDY). The atomic structures of monolayer graphdiyne (MGDY), bilayer AB(β1)‐stacking graphdiyne (AB(β1)BGDY) and nitrogen‐doped AB(β1)BGDY (N‐AB(β1)BGDY) at different lithiation states were thoroughly investigated. The AB(β1)BGDY and N‐AB(β1)BGDY exhibit promising characteristics in Li‐ion adsorption and intercalation, enhancing its specific capacity from 744 mAhg‐1 in the monolayer GDY to 807 mAhg‐1 in the bilayer. Besides increasing the capacity through a bilayer‐structure, it is possible to tailor its structural stability and band gap by doping. Especially shown for N‐AB(β1)BGDY (~1%), an increased structural stability and a decreased band gap of 0.24 eV is found. While this means that N doping in AB(β1)BGDY can lead to longer‐lasting and more stable operatable high‐capacity anodes in LIBs, it increases the OCV.

Scalable Self-Assembly of Composite Nanofibers into High-Energy-Density Li-Ion Battery Electrodes.

The application of nanosized active particles in Li-ion batteries has been the subject of intense investigation, yielding mixed results in terms of overall benefits. While nanoparticles have shown promise in improving rate performance and reducing issues related to cracking, they have also faced criticism due to side reactions, low packing density, and consequent subpar volumetric battery performance. Interesting processes such as self-assembly have been proposed to increase packing density, but these tend to be incompatible with scalable processes such as roll-to-roll coating, which are essential to manufacture electrodes at scale. Addressing these challenges, this research demonstrates the long-range self-assembly of carbon-decorated V2O5 nanofiber cathodes as a model system. These nanorods are closely packed into thick electrode films, exhibiting a high volumetric capacity of 205 mA h cm-3at 0.2 C. This surpasses the volumetric capacity of unaligned V2O5 nanofiber electrodes (82 mA h cm-3) under the same cycling conditions. We also demonstrate that these energy-dense electrodes retain an excellent capacity of up to 190.4 mA h cm-3(<2% loss) over 500 cycles without needing binders. Finally, we demonstrate that the proposed self-assembly process is compatible with roll-to-roll coating. This work contributes to the development of energy-dense coatings for next-generation battery electrodes with high volumetric energy density.

Conducting LixPOy Interface Generated From Insulating Residual Lithium Compounds on LiNi0.8Mn0.1Co0.1O2 Surface Improves Cycle Life and Assists in Fast Cycling.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for future Li-ion batteries (LIBs). However, the bulk and surface structural instabilities retard its commercial success. Surface chemical instability toward exposure to moisture (H2O and CO2) leads to the formation of residual lithium compounds (RLCs: Li2CO3, LiOH) on the surface. The alkaline RLCs form a resistive layer on the surface of NMC811 by undergoing parasitic side reactions with electrolytes. Herein, an "Adverse-to-Beneficial" approach is proposed to eliminate RLCs by chemically transforming them into a LixPOy (Li3PO4 and LiPO3) interface. The interface protects the NMC811 surface from moisture attack and unwanted side reactions with electrolytes. It enhances the cycle life by retaining 70% of the initial capacity after 300 cycles at a 0.5C rate and 60% after 500 cycles, even at a 5C rate in a voltage window of 3.0-4.3V versus Li+/Li. The coexistence of two Li-conducting phases lowers the voltage polarization of the kinetically sluggish H1 → M phase transition to unlock fast cycling, reduces cationic disorder, improves coulombic efficiency, enhances ion diffusion kinetics, and minimizes particle crack formation after long-term cycling. Hence, the LixPOy interface yields multifaceted benefits in the storage, processing, and electrochemistry of NMC811.

Iterative sizing methodology for photovoltaic plants coupled with battery energy storage systems to ensure smooth power output and power availability

Photovoltaic (PV) solar energy is a fundamental technology that will help transition from a fossil fuel–based energy mix to a future with high shares of renewable energy. To do so, PV plants coupled with energy storage systems can accumulate excess power and dispatch it when PV generation changes, performing PV smoothing. While coupling PV plants with battery energy storage systems (BESS) offers a solution, current methodologies often need to thoroughly describe the interplay between BESS energy capacity, power rating, and the long–term impacts of battery degradation. This paper addresses this gap by proposing a four–step methodology that optimizes BESS sizing for PV plants, accounting for both cycling and calendar aging effects on system performance and the economic implications of battery replacements. We use a model that considers the degradation of PV modules and two Li–ion battery types (LiFePO4, LFP, and LiNiMnCoO2, NMC). A 16.3 MW PV plant is simulated along with the BESS to test the methodology. The results indicate that an LFP–based BESS of 2.5 MWh with a rated power of 1.25 MW ensures a stable output power with variation below 10% of the rated PV plant 98 % of the time. In contrast, an NMC–based BESS, while effective in reducing non–compliance, incurs higher costs due to more frequent battery replacements, making it less economically viable. The methodology and results presented in this paper provide valuable insights for designing cost–effective and reliable energy storage solutions in PV plants, ensuring compliance with set power availability.

Quantitative Analysis of the Li-Ion Solvation Structure in Li-Ion Battery Electrolytes Using ATR-FTIR Spectroscopy.

Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy is widely used to study condensed materials due to its convenient sample preparation and ability to avoid absorption saturation. Recently, it has been applied to in situ and in operando observations of chemical reactions within electrochemical devices, such as lithium-ion batteries. However, because ATR-FTIR spectroscopy relies on frequency-dependent attenuated reflectance, quantitative concentration measurements of chemical species using the Beer-Lambert law are challenging. Despite the availability of several correction methods, discrepancies remain in the solvation structures around Li+ ions when comparing transmission-type FTIR and ATR-FTIR spectroscopy results, which complicate the determination of solvation and desolvation energies. In this study, we investigate ATR-FTIR correction algorithms, elucidate the reasons for the discrepancies between ATR-FTIR and transmission FTIR spectroscopy results, and develop a method to correct the ATR-FTIR spectrum to accurately determine the solvation structures around Li+ ions.

Rational design of the temperature-responsive nonflammable electrolyte for safe lithium-ion batteries

The development of nonflammable electrolytes is critical for breaking the trade-off between the safety and energy density in Li-ion batteries (LIBs). Here, a rational design strategy of temperature-responsive nonflammable electrolytes (TRNEs) is proposed which are capable to prevent the heat accumulation and extinguish the fire efficiently during thermal runaway. Compared to the conventional phosphate- or halogen-based flame retardants, the TRNE based on low-cost and multifunctional methylurea (MU) was demonstrated with the lowest volatility (11.6 % weight loss) below 250 °C, and the highest efficacy to extinguish the fire at >210.4 °C through heat absorption, inert gases generation and char layer formation. In addition, the developed MU-based TRNEs enable higher stability and rate capability of LIBs compared to various nonflammable electrolytes. A Li||LiFePO4 (LFP) cell employing MU-based TRNE achieved higher stability (94.9 % capacity retention for 1500 cycles) than commercial electrolyte. A Ni-rich Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) system was demonstrated with superior rate capability and high stability for 700 cycles (2.72 months) with the capacity retention of 89.9 %. Combining low cost and volatility, as well as high stability, rate capability and fire extinguishing efficacy, we demonstrate a promising design strategy to improve the battery safety for high-energy-density LIBs.

Dynamic interface layer enables epitaxial Li deposition for anode-free Li metal batteries

Anode-free Li-metal batteries are the best high-energy-density Li-ion batteries. However, the lack of active Li on anode side exacerbates dendritic Li growth, dead Li formation and parasitic reactions. In this study, we develop a lithiophilic Mg modification layer on Cu foil surface using magnetron sputtering. The epitaxial and dense Li deposition are manipulated, attributing to excellent Li affinity, favorable charge transfer and self-diffusion kinetics of the functional layer. Consequently, the coulombic efficiency of Li deposition/stripping on the Mg-coated Cu substrate remains at 83.7 % even after 50 cycles under 0.5 mA cm−2. Importantly, this approach enable the pouch cells paired with LiFePO4 cathodes to achieve a lifespan of over 70 cycles under 0.5 mA cm−2 without experiencing a significant capacity drop. This straightforward strategy is promising for developing long-lasting anode-free Li batteries.

Thermal management analysis with different PCMs in Sodium-Ion batteries

The advent of modern technology has led to a significant increase in the utilisation of rechargeable secondary batteries. Despite the sustainability of lithium-ion (Li-ion) batteries, the limited availability of lithium has driven research into alternative energy storage technologies. Sodium-ion (Na-ion) batteries, as a potential alternative to Li-ion batteries, have emerged as a highly promising contender. However, for these batteries to become industrially viable, certain properties such as energy and power density need to be enhanced. To address this issue, batteries have been a focus of research, and battery thermal management systems have been developed. These systems aim to evaluate battery performance, which is strongly influenced by temperature. Effective thermal management ensures that the battery operates within the optimal temperature range. This study models a pouch-type battery and evaluates the effects of phase changing materials (PCM) on battery temperature control. Comparative analysis is conducted using different PCMs to understand their impact. The study analyses the battery's response to specific temperature ranges and assesses how different PCMs affect battery cooling performance. The results provide critical insights for ensuring efficient battery operation. Furthermore, this research supports the broader adoption of Na-ion batteries in industrial applications and contributes to the development of sustainable energy storage systems.