Application In Lithium-ion Batteries Research Articles

Advanced Lithium Batteries and Fast-Charging Technology: Challenges and Future Directions

Lithium-ion batteries (LIBs) are essential for advancing electric vehicles (EVs) and consumer electronics, offering high energy density and fast-charging capabilities. Nanotechnology, like incorporating polyaniline-modified graphene composites (PMGCs), has significantly enhanced ion diffusion and electron conductivity. However, key challenges persist, including thermal management, solid electrolyte interphase (SEI) layer growth, and charger compatibility. Safety concerns, such as thermal runaway caused by ohmic losses, underscore the need for advanced battery management systems (BMS) and innovative electrolytes. Solid-state batteries (SSBs) present a promising future with higher safety and energy density, yet they are still under development. During the transition, optimizing LIBs through material improvements and charging technologies will be vital to maintaining their market dominance. Enhancing safety measures, including better BMS and more stable electrolytes, is crucial for the continued application of LIBs in EVs, portable devices, and other high-demand sectors. These strategies will ensure LIBs remain competitive until SSBs are commercially viable.

Conjugated Phthalocyanine-Based Mesoporous Covalent Organic Frameworks for Efficient Anodic Lithium Storage.

Organic anode materials have been recognized as promising candidates for low-cost and sustainable lithium-ion batteries (LIBs), which however suffer from the inferior cycling stability and low conductivity with unsatisfactory LIBs performance. Herein, two conjugated phthalocyanine-based covalent organic frameworks (COFs), namely CoPc-Ph-COF and CoPc-3Ph-COF, are synthesized by the nucleophilic substitution reaction of hexafluorophthalocyanine cobalt (II) (CoPcF16) with 1,2,4,5-tetrahydroxybenzene and 9,10-dimethyl-2,3,6,7-tetrahydroxyanthracene, respectively. Powder X-ray diffraction and electron microscopy analysis reveal the crystalline porous structure of both COFs with a pore size of 1.6-2.4nm, enabling facile ion transportation. Immersion experiments demonstrate the excellent stability of both COFs. I-V curve measurement discloses the superb conductivity of both COFs due to their fully π-conjugated frameworks. These merits, in combination with their N-rich skeleton, endow the two COFs with excellent anodic Li+ storage performance in terms of high specific capacities, superb rate performance, and good cycling stability. In particular, CoPc-3Ph-COF suggests a large reversible capacity of 1086mA h g-1 at 100mA g-1, superior to most reported organic LIBs anodes, exhibiting its promising application in high-performance LIBs.

Thermophysical properties of choline chloride:4ethylene glycol and LiPF6 mixtures for lithium battery applications

Thermophysical properties of choline chloride:4ethylene glycol and LiPF6 mixtures for lithium battery applications

Polymerizable Ionic Liquid-Based Gel Polymer Electrolytes Enabled by High-Energy Electron Beam for High-Performance Lithium-Ion Batteries.

Polymerizable ionic liquid-based gel polymer electrolytes (PIL-GPEs) were developed for the first time using high-energy electron beam irradiation for high-performance lithium-ion batteries (LIBs). By incorporating an imidazolium-based ionic liquid (PIL) into the polymer network, PIL-GPEs achieved high ionic conductivity (1.90 mS cm-1 at 25 °C), a lithium transference number of 0.62, and an electrochemical stability exceeding 5 V. E-beam irradiation enabled rapid polymer network formation within a metal-cased battery structure, eliminating the need for initiators and improving the process efficiency. In the NCM811/PIL-GPE/Li cells, PIL-GPE (8:2) delivered an initial discharge capacity of 198.8 mAh g-1 with 82% retention at 100 cycles, demonstrating enhanced thermal stability and cycling performance compared to traditional GPEs. The demonstrated PIL-GPEs demonstrate strong potential for high-stability, high-performance LIB applications.

Untreated bamboo biochar as anode material for sustainable lithium ion batteries

Biochar, a carbon-rich material derived from lignocellulose biomass through pyrolysis, is being considered for lithium-ion battery (LIB) applications due to its sustainable sourcing, manufacturing, and favourable electrochemical properties. A biochar-based anode is a greener alternative to conventional materials, potentially reducing the environmental and financial costs of LIB production. Minimizing cost and simplifying the manufacturing process for LIBs drive the development of new scalable production of plant-based products to create greener anodes for lithium batteries. In this work, bamboo-based biochar (BCs) was prepared through an optimized slow pyrolysis route with two thermal treatments at 800 °C (B800) and 1000 °C (B1000), and used as a LIB anode. Compared to B1000, B800 presented higher d-spacing (d002 = 0.3657 nm) and graphitic crystallite size (La = 13.8 nm), smaller pore sizes (38 Å) with higher surface area (310 m2/g), and a higher concentration of permanent free radicals (PFRs) centered on the carbon (1.85 × 1018 spin/g). Although B1000 is slightly more conductive than B800, the physicochemical properties of B800 could enhance the lithiation of the pseudographitic structures and facilitate the reduction of Li+ ions due to the presence of PFRs. The half-cell LIB using B800 presented a reversible capacity of about 250 mA h/g at C/5 and long-term stability up to 450 cycles. This study highlights the potential of bamboo-based biochar as a viable and environmentally friendly anode material for the next generation of high-performance LIBs.

Enhanced lithium-ion storage through anchoring nanocrystalline MoO2/C microspheres in rGO nanosheets: Boosting pseudocapacitance and facilitating rapid conversion

Both crystalline and amorphous MoO2 exhibit distinct advantages for lithium-ion battery applications, with the former favoring lithium-ion intercalation and the latter undergoing complete lithiation via a conversion reaction. However, their sluggish lithium-ion insertion rates and inadequate charge transfer kinetics hinder their full potential. To address these challenges, we have developed a controllable approach that integrates liquid-phase dispersion of the HxMoO3/C and graphene oxides (GO) precursors followed by freeze-drying and low-temperature calcinations, aiming to merit the ionic conductivity of MoO2/C nanocrystallite and the electronic conductivity of reduce graphene oxides (rGO), respectively. This facile method yields bubble-sheet-like MoO2/C@rGO composites, where the quantitatively strategic incorporation of rGO can effectively mitigate recrystallization and surface oxidation of MoO2 nanocrystals. Furthermore, the approximately 70 % volume shrinkage of HxMoO3/C precursors into MoO2/C can create a flexible void space between the microspheres and the rGO coating for better accommodating volume variations during lithiation. Electrochemical measurements show that MoO2/C@rGO delivers high initial coulombic efficiency (ICE, e.g., up to 71.3 % at 100 mA g⁻¹), impressive rate performance (e.g., achieving 60 mA h g⁻¹ at 1 A g⁻¹, and 34.1 % retention from 0.1 to 2 A g⁻¹) and excellent cyclability (e.g., retaining 98.9 % of its capacity after 200 cycles) when employed as an intercalation-type anode material above 1.00 V (vs. Li/Li⁺). Remarkably, electrochemical analysis indicates that the capacitive contribution is dominant during high-rate applications (e.g., up to 73.06 % ratio at a scan rate of 0.50 mV s⁻¹), exhibiting a pseudocapacitive behavior. Additionally, MoO2/C@rGO exhibits enhanced ICE (e.g., up to 76.9 % at 100 mA g⁻¹), accelerated activation (e.g., achieving peak performance within 10 cycles at 100 mA g⁻¹), superior rate performance (e.g., achieving 446 mA h g⁻¹ at 2 A g⁻¹), and remarkable cyclability (e.g., maintaining 510 mA h g⁻¹ with 88.9 % capacity retention over 600 cycles at 1 A g⁻¹) when applied as a conversion-type anode material at between 1.00 and 3.00 V (vs. Li/Li⁺). To elucidate the mechanisms underlying the high-rate performance and the increased capacity, ex-situ XRD, ex-situ SEM, ex-situ TEM, and electrochemical analysis were carried out. No evident phase transition or material pulverization can be observed upon cycling above 1.00 V; therefore, the structural evolution is entirely single-phase or solid-solution, which accompanies with pseudocapacitive characteristic. However, the diffraction peaks downshift, the eminent of LixMoO2+δ, the pulverization, and the gradual amorphization of MoO2 can be observed upon cycling, indicating an sequential intercalation-to-conversion activation from a crystalline state to an amorphous state.

Polypyrrole as the MOFs/polymer interfacial binder applied in mixed matrix porous separator for high temperature safe lithium-ion batteries

Uniform distribution of two-dimensional (2D) metal organic frameworks (MOFs) in polymer composites is crucial for fabricating mixed matrix porous separators (MMPS) for metal-ion (M+) batteries (MIBs). However, effectively incorporating 2D MOFs into mechanically robust and highly transportive MMPS, without agglomeration and leaching, has been challenging. Herein, we report the post-polymerization of polypyrrole (PPy) on 2D Cu-MOFs nanosheets, and their uniform distribution in the poly-(arylene ether benzimidazole) (OPBI) to prepare highly porous and mass transportive MMPS using non-solvent induced phase separation (NIPS) method for lithium ion (Li+) batteries (LIBs) applications. The polymerization of PPy not only improved the dispersibility of the Cu-MOFs nanosheets, but also acted as an interfacial binder, ensuring compatibility between the MOFs and OPBI chains. The PPy@Cu-MOFs nanosheets increased the pore size and porosity of the OPBI-based MMPS, creating wider and more uniform cross-sectional channels, thereby enhancing Li+ flux between the anode and cathode during battery charge/discharge cycles. The thermally stable, electrolyte-affinitive, and lithophilic PPy@Cu-MOFs/OPBI MMPS, when assembled in LIBs, achieved a discharge capacity of 150.2 mAh· g−1 with sustained performance over 200 cycles, showing no capacity fading even at elevated temperature. This work provides new insights into polymerizing conjugated polymer on 2D-MOFs nanosheets for improved dispersibility and uniform distribution, enabling the design of high-performance, mass transportive MMPS for safe LIBs application to meet current green energy demands.

Rechargeable Li-Ion Batteries, Nanocomposite Materials and Applications

Lithium-ion batteries (LIBs) are pivotal in a wide range of applications, including consumer electronics, electric vehicles, and stationary energy storage systems. The broader adoption of LIBs hinges on advancements in their safety, cost-effectiveness, cycle life, energy density, and rate capability. While traditional LIBs already benefit from composite materials in components such as the cathode, anode, and separator, the integration of nanocomposite materials presents significant potential for enhancing these properties. Nanocomposites, including carbon–oxide, polymer–oxide, and silicon-based variants, are engineered to optimize key performance metrics, such as electrical conductivity, structural stability, capacity, and charging/discharging efficiency. Recent research has focused on refining these composites to overcome existing limitations in energy density and cycle life, thus paving the way for the next generation of LIB technologies. Despite these advancements, challenges related to high production costs and scalability remain substantial barriers to the widespread commercial deployment of nanocomposite-enhanced LIBs. Addressing these challenges is essential for realizing the full potential of these advanced materials, thereby driving significant improvements in the performance and practical applications of LIBs across various industries.

Composite Polymer Electrolyte Based on PAN/TPU for Lithium-Ion Batteries Operating at Room Temperature.

Lithium-ion batteries have garnered significant attention owing to their exceptional energy density, extended lifespan, rapid charging capabilities, eco-friendly characteristics, and extensive application potential. These remarkable features establish them as a critical focus for advancing next-generation battery technologies. However, the commonly used organic liquid electrolytes in batteries are explosive, volatile, and possess specific toxic properties, resulting in persistent safety concerns that remain to be addressed. Composite polymer electrolytes (CPEs) exhibit enhanced safety and stable electrochemical performance, emerging as one of the most promising alternatives. However, single polymers often need to meet the multifaceted performance requirements of batteries. In this study, a composite polymer electrolyte was prepared using solution casting, consisting of a blend of polyurethane (TPU) and polyacrylonitrile (PAN), along with the ceramic filler Li1.3Al0.3Ti1.7(PO4)3 (LATP) and lithium perchlorate (LiClO4). The optimal formulation, which included 40 wt% TPU, 60 wt% PAN, and 10 wt% LATP, exhibited a commendable ionic conductivity of 2.1 × 10-4 S cm-1, a lithium-ion transference number (tLi+) of 0.60, and notable electrochemical stability at 30 °C. The LiFePO4/Li battery assembled with this CPE demonstrated excellent cycling stability and rate capability at room temperature. It delivered a discharge specific capacity of 130 mAh g-1 at 1C. Under a charge-discharge rate of 0.2C, the battery achieved a discharge specific capacity of 168 mAh g-1, retaining 98% of its capacity after 100 cycles at 25 °C. Additionally, the CPE exhibited robust safety performance. Consequently, this composite polymer electrolyte holds significant promise for application in lithium-ion batteries.

The Role of Asymmetry of Perfluoro anion in Ionic Liquids: From Basic Physical Properties to the Application in Lithium Batteries

From the late 1990s, room temperature molten salts composed of stable perfluoro anion became known as ionic liquids and have been widely recognized and applied in various fields of chemistry for almost three decades. Our research focuses on the use of aliphatic quaternary ammonium cations (AQA) as electrolytes for lithium secondary batteries, which possess unique properties of non-volatility, non-flammability and relatively wide electrochemical window that cannot be achieved with conventional electrolytes. To improve battery performance by reducing the internal resistance of the battery system, we investigated various perfluoro anion as shown in Figure 1. From these studies we concluded that the rate characteristics of lithium secondary batteries with ionic liquids depend not only on viscosity, which governs the diffusion of Li+, but also on the chemical structure of the perfluoro anion, which govern the interaction between Li+ and the anions.1)-3) On the other hand, through these studies, we found that the asymmetry of the anion structure 4)-6) and the ether oxygen in the anion side chain7) have significant effects on thermal and transport properties of the ionic liquid, similar to the asymmetry of the cation represented by 1-ethyl-3-methylimidazolium and the ether oxygen in the side chain represented by N,N-dimethyl-N-ethyl-N-(2-methoxyethyl)ammonium. The most striking results are obtained by lithium (fluorosulfonyl) (trifluorosulfonyl) amide (LiFTA)8), which exhibits a relatively low melting point (T m = 100 °C) among the Li salts and has applications in battery electrolytes 8) and unique electrochemical properties9). Here, we would like to show the importance of developing new anion species that give rise to novel ionic liquids and alkali metal salts based on our results.1) H. Matsumoto, Y. Miyazaki, and H. Ishikawa, Japanese Patent Application (1998).2) H. Matsumoto, “Electrochemical window of Room Temperature Ionic Liquids”,Electrochemical Aspects of Ionic Liquids (Ed. H. Ohno), Wiley (2005).3) H. Matsumoto, Recent advances in Ionic Liquids for Lithium Secondary Batteries: Modern Aspects of Electrochemsitry No.58,: Electrolytes for Lithium and Lithium-Ion Batteries, Eds. T. R. Jow, K. Xu, O. Borodin, and M. Ue, chapter 4, Springer, 2014.4) H. Matsumoto, H. Kageyama, and Y. Miyazaki, Chem. Commun., 1726 (2002).5) H. Matsumoto, H. Sakaebe, and K. Tatsumi, J. Power Sources, 146(1–2), 45 (2005).6) H. Matsumoto, N. Terasawa, T. Umecky, S. Tsuzuki, H. Sakaebe, K. Asaka, and K. Tatsumi, Chem. Lett., 37(10), 1020 (2008).7) Terasawa, S. Tsuzuki, T. Umecky, Y. Saito, and H. Matsumoto, Chem. Commun., 46(10), 1730 (2010).8) Kubota, and H. Matsumoto, J. Phys. Chem. C, 117(37), 18829 (2013).9) H. Sano, K. Kubota, Z. Shiroma, S. Kuwabata, and H. Matsumoto, J. Electrochem. Soc., 167(7) 070502 (2019). Figure 1

N, P Co-Doped Hard Carbon Anodes for High-Performance Lithium-Ion Batteries with Enhanced Capacity Retention and Cycle Stability.

Compared to the traditional graphite anode, heteroatom-doped polymer carbon materials have high capacity retention due to their high porosity and porous structure. Therefore, they have great potential for application in lithium-ion battery (LIB) anodes. In this work, an N, P co-doped precursor polymer material (MBPp), synthesized via a one-pot method using bisphenol-A (C-source), melamine (N-source), and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (P-source). The resulting N, P-co-doped hard carbon materials (MBPs) were prepared at various pyrolysis temperatures, yielding microporous, mesoporous, and macroporous structures. MBP materials demonstrated excellent electrochemical performance as LIB anodes. Notably, MBP-900 achieved a reversible capacity of 262 mAh g-1 at 1000 mA g-1 (in 0.005-2.0 V voltage range) with a capacity retention rate of 97.1 % after 1000 cycles. These findings highlight the significance of MBP materials, which possess numerous defects, large layer gaps, and excellent cycle stability, in advancing the development of polymer anode materials for LIBs.

Influence of Oxygen Defects on Electrochemical Performance of Ni-Rich Layered Oxides for Future Lithium-Ion Batteries

Ni-rich layered cathode active materials (CAMs) are promising candidates for application in lithium-ion batteries due to their high reversible capacity. To further improve the performance of lithium-ion batteries, changing the transition metal composition in CAMs is a good approach to gain a higher capacity, better capacity retention as well as higher rate capability and safety. The oxygen lattice has been considered and widely accepted to be electrochemically inactive, even though it plays a key role in the phase transformations that occur at high degrees of delithiation, as oxygen is released during these high delithiation states. In addition, released oxygen can cause thermal runaway, by exothermic reaction with electrolyte 1,2. However, the effect of oxygen defects and vacancies on the electrochemical performance of cathode active materials in lithium-ion batteries has been scarcely investigated. Research has mainly focused on lithium-rich layered materials, where oxygen vacancies have led to improved battery performance in terms of rate capability, higher discharge capacity and reduced oxygen evolution 3. However, many of these publications suffer from an unprecise content of oxygen deficiencies within the cathode active material with large errors. In this work, a solid-state reactor for electrochemical extraction of oxygen is used to obtain an accurate oxygen deficiency with low error for Ni-rich layered NCM 811 4. Using this process, 1 mol%, 2 mol% and 5 mol% oxygen deficient NCM 811 are produced and (electro)chemically characterized. The effect of oxygen defect concentration on discharge capacity, capacity retention, rate capability and structural stability is investigated in liquid cells. In addition, electrochemical impedance spectroscopy (EIS) is used to reveal changes in electrode resistances. To obtain the cathode impedance only, a three-electrode setup is used, which utilizes a μ-reference electrode made of gold wire.References 1 R. Jung, M. Metzger, F. Maglia, C. Stinner and H. A. Gasteiger, J. Electrochem. Soc., 164, A1361 (2017). 2 R. Jung, P. Strobl, F. Maglia, C. Stinner and H. A. Gasteiger, J. Electrochem. Soc., 165, A2869 (2018). 3 B. Qiu, M. Zhang, L. Wu, J. Wang, Y. Xia, D. Qian, H. Liu, S. Hy, Y. Chen, K. An, Y. Zhu, Z. Liu, and Y. S. Meng, Nat. Commun., 7, 12108 (2016). 4 T. Nakamura, H. Gao, K. Ohta, Y. Kimura, Y. Tamenori, K. Nitta, T. Ina, M. Oishi and K. Amezawa, J. Mater. Chem. A, 7, 5009 (2019).

Nano-Structuring Strategies of Ti/Sn Oxides Produced from MAX Phases to Achieve Efficient Anodes for Alkaline Ion Batteries

One of the most promising technologies to support lithium-ion batteries (LIB) to follow the growing demand of electrochemical storage devices, particularly for stationary applications, are sodium-ion batteries (NIB). Despite both technologies sharing operating principles, first of all the ion rocking chair mechanism between cathode and anode, it is always difficult to find materials able to exchange ions between battery electrodes quickly and reversibly. While the use of graphite as an anode is a well-established application in LIB; for NIB, hard carbons are currently the most exploited solution, both in laboratory research and upcoming industrial products expected to hit the market in the coming years. The performance of these compounds is heavily reliant on fine control over the synthesis process and the nature of carbonaceous precursors.Over the years, as materials generations change, the anodic side of LIB has also been under study to increase volumetric capacity beyond that of graphite, as well as to improve device safety by reducing the flammability of constituents [1].Another way to develop high-performance LIB and NIB anodes is to exploit the conversion/alloying processes that some compounds/elements exhibit with lithium and sodium. This approach has always been less promising due to strong irreversible capacity lost cycle by cycle due to the poor stability of the materials and the strong volumetric expansions involved. To minimize these phenomena, it is essential to push the grain size of electro-chemically active compounds to the nanometer scale. The strategy used in this work to easily produce nano-structured oxides able to convert/alloy with Li/Na was based on a controlled thermal treatment in air of lamellar carbides known as MAX phases. Specifically, for the first time, powders of Ti3Al(1-x)SnxC2 MAXPhase (synthesized by Spark Plasma Sintering method) were oxidized treated at various temperatures at tested as NIB anode. Samples obtained by varying the Sn concentration and the thermal process parameters were characterized both at a chemical-physical and electrochemical level in half-cells. XRD, SEM, EDX, TEM and Raman (in operando) measurements were used to study the self-nano-structuration process of the oxides on the surface of the original MAX phase [2] and to deeply investigate the storage mechanisms involved. The structural analysis revealed the presence of mixed Ti/Sn oxides with variable composition and structure depending on the process parameters. The aim of the study was to correlate the properties of the oxidized powders with the electrochemical performances in order to maximize the final ion accumulation properties. Preliminary electrochemical tests led to current C/10 capacity values of ≈300 mAh/g (vs Li+/Li) and ≈170 mAh/g (vs Na+/Na) with both cases Coulombic Efficiency >99%.[1] X. Ding, Q. Zhou, X. Li, and X. Xiong, “Fast-charging anodes for lithium ion batteries: progress and challenges,” Chemical Communications, vol. 60, no. 18, pp. 2472–2488, 2024, doi: 10.1039/D4CC00110A.[2] I. Ostroman et al., “Highly Reversible Ti/Sn Oxide Nanocomposite Electrodes for Lithium Ion Batteries Obtained by Oxidation of Ti 3 Al (1‐x) Sn x C 2 Phases,” Small Methods, vol. 7, no. 10, pp. 1–15, Oct. 2023, doi: 10.1002/smtd.202300503.

Optimization of Hybrid Pulse Power Characterization (HPPC) Protocol for Lithium-Ion Battery Diagnostics

The importance of accurate diagnostics in lithium-ion battery applications has received increasing emphasis, especially after the formation step to assess the quality of the solid-electrolyte interphase layer and before second-life usage to investigate whether the recycled battery meets safety and performance requirements [1, 2]. Among diagnostic methods, hybrid pulse power characterization (HPPC) tests are promising as they extract relatively large information from high-rate perturbations from a near-equilibrium state by undergoing a sufficiently long rest step before applying the pulses [3]. However, traditional HPPC protocols (that is, using fixed magnitudes of charge/discharge pulses at uniformly distributed states of charges) provide superficial information about the battery health by only capturing the convoluted symptoms instead of investigating the physical cause of the degradation [3]. To overcome this limitation, a novel diagnostic method of using voltage pulses for HPPC protocols (i.e., smart HPPC) was proposed to successfully separate the impact of the individual degradation mechanisms on current responses [3].While smart HPPC has shown decent performance in identifying individual degradation mechanisms such as film resistance, surface blockage, and electrolyte loss, this work aims to make the protocol even smarter by (1) designing reaction model/electrode material-specific HPPC protocols, (2) performing a quantitative identifiability analysis by considering the uncertainty of estimated degradation parameters, (3) validating the robustness of designed HPPC protocols by performing simulations in various hypothetical situations, and (4) incorporating information from the previous diagnostic results to improve the next round of diagnostics. In this work, a novel framework for designing a set of optimal HPPC protocols is described which is composed of three steps: (1) formulating the parametric uncertainty using a model-based design of experiment (DOE) method and the diagnostic time using scaling analysis, (2) constructing a Pareto front by solving a two-objective optimization, and (3) evaluating the robustness of the designed HPPC protocol by performing Markov Chain Monte Carlo (MCMC) simulations with various degradation states. This work demonstrates the application to a Nickel-Cobalt-Aluminum (NCA)-graphite electrode full-cell with the coupled ion-electron transfer (CIET) reaction model. Our framework could reduce the total diagnostic time by up to 45% of the traditional HPPC protocol while retaining accuracy for identifying all degradation mechanisms.The information dependency on the state of charge (SOC) is investigated in our work through simulation results from overpotential-balanced full cells, showing that the pulses performed with the lower filling fraction of the overpotential dominant electrode are more informative than the pulses with the higher filling fraction. This result allows us to design an innovative shallow-depth HPPC protocol that only explores the SOC regions with high information, which dramatically reduces the total diagnostic time.

Conversion Mechanism-Driven Lithium Storage in Sr2CoMoO6 Double Perovskite for High-Performance Anode

The dominance of graphite as the anode material in Lithium-ion batteries (LIBs) is challenged by its inherent limitations. The restricted theoretical capacity of 372 mAh/g impedes its ability to satisfy the escalating demands for high-energy density storage solutions [1-3]. Furthermore, lithium plating during cycling raises serious safety concerns, and graphite exhibits poor capacity retention at high current densities [4]. To address these shortcomings, the development of anode materials with superior capacity, exceptional cycling stability, and enhanced safety characteristics is of prime importance. Conversion reactions present a compelling strategy for achieving significantly higher capacities compared to the conventional intercalation/deintercalation mechanisms employed in commercial LIBs [5-6]. These reduction processes involve the transformation of the electrode material during discharge into metal nanoparticles dispersed within a Li2O matrix. This approach offers a promising avenue to overcome the limitations of traditional intercalation mechanisms. Perovskite frameworks, with their diverse functionalities and unique crystal structures, have emerged as attractive candidates for energy storage applications due to their inherent ability to accommodate a wide range of cations [7]. This structural flexibility allows for the design of materials with properties tailored for specific electrochemical applications. Double perovskites (DPs), a subclass of perovskites with ordered B-site cations, present a particularly promising avenue for exploration as anode materials.This study investigates the electrochemical performance of Sr2CoMoO6 (SCMO), a novel double perovskite synthesized via both solution-combustion and solid-state methods, as a potential high-capacity anode material for LIBs. A systematic half-cell configuration was employed for the evaluation of its anodic behaviour. To gain a deeper understanding of the structure and morphology, a comprehensive suite of advanced characterization techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), was utilized.SCMO exhibits exceptional electrochemical performance, demonstrating a superior reversible capacity of 575 mAh/g during the initial discharge cycle in LIBs. Notably, the material showcases remarkable cycling stability, retaining an impressive 540 mAh/g after 250 cycles at a current density of 100 mA/g. This excellent performance is achieved within a broad potential window of 0.01-2.5 V, signifying the versatility of our material for practical battery applications. Furthermore, SCMO demonstrates remarkable rate capability, maintaining stable capacity across a wide range of current densities. This highlights the ability to deliver high power output, a crucial parameter for various portable electronic devices. To gain deeper insights into the underlying lithium storage mechanism, ex situ characterization employing XRD, XPS, SEM, and TEM was performed after cycling. The analyses revealed a conversion-dominated process, where Sr2CoMoO6 undergoes reduction to dispersed CoO and MoO3 nanophases embedded within an electrochemically inactive Li2O matrix. This analysis suggests that the high capacity achieved by SCMO originates from the conversion reaction mechanism. These compelling findings strongly advocate for the strategic design of DPs that exploit conversion mechanisms for lithium storage. This approach offers a promising avenue to significantly enhance the overall electrochemical performance of DP electrodes in LIB applications. By harnessing the unique properties of DPs and optimizing the conversion reaction process, researchers can develop next-generation anode materials with superior capacity, exceptional cycling stability, and improved safety characteristics. This paves the way for the development of high-performance LIBs that can meet the demands of the ever-evolving energy landscape. Figure 1

Exploring Binderless Tin and Hard Carbon Anodes Via Electrospray Deposition for Sodium-Ion Batteries

For decades, lithium-ion batteries have seen widespread usage in a variety of applications from consumer electronics such as smartphones to the more recent developments of electric vehicles. As the usage of lithium for batteries increases, one growing concern is the finite amount that could be found within the Earth’s crust. An alternative that is being considered is sodium-ion batteries due to how plentiful sodium is in the Earth’s crust and similar chemical properties to lithium. One of the main challenges of sodium-ion batteries is the development of anode materials because sodium does not intercalate well with graphite, which is one of the most used materials in lithium-ion batteries. One promising development for anode materials is the use of hard carbon derived from the pyrolysis of polymers such as polyacrylonitrile (PAN) which can have various morphologies and potential for adding other high-capacity components to boost the performance. One material that has received attention is tin which has been previously added into electrospun carbon nanofibers with applications in both lithium and sodium ion batteries. They often include sacrificial materials such as polymethyl methacrylate (PMMA) to produce tin and porous carbon composite nanofibers. While tin on electrospun carbon nanofibers have been studied, there is little work that has been done with the structures that can be produced through electrospray deposition. Thus, our work seeks to explore the development of tin and hard carbon anodes via electrospray deposition with and without air assistance. This will allow for an increased loading of tin as well as exploration of the performance of hard carbon anodes with different structures in sodium ion batteries. Through the use of electrospray deposition, with and without air assistance, the performance of different morphologies such as microdisks, nanospheres, and thin films can be tested with a greater variation in tin concentrations that can exceed the mass of the precursor polymer. Further variation can be introduced by varying the porosity of the structures by introducing PMMA into the spray solutions at different concentrations. The use of electrospray deposition also allows for the production of binderless anodes by coating directly onto the current collector, promising for light-weight batteries development.

Saturation-Based Transport Limitation in Thick Electrodes with Conventional Carbonate Electrolytes

In electric vehicles, stationary grid storage, and low-power lithium-ion battery (LIB) applications, thick electrodes can minimize inactive material use to increase energy density and decrease costs but face challenges in performance and manufacturability. In thick electrodes, large concentration gradients form across the electrode to push lithium ions through the thickness of the electrode, resulting in large concentration overpotentials that limit capacity utilization at higher rates. It is well understood that lithium-ion depletion at one side of this concentration gradient results in a limiting current for the cell; our models show that for high-power thick electrode systems, salt accumulation at the other side of the concentration gradient exceeds the solubility of conventional carbonate electrolytes used in LIBs. In this study, ~1mm thick dry-pressed lithium iron phosphate (LFP) electrodes were cycled at various current densities to explore precipitation conditions. Thick electrodes become rate-limited in a hexafluorophosphate (PF6)-based carbonate electrolyte; they are able to maintain high capacity utilization (~98% at C/10, ~95% at C/5, ~76% at C/2) in a bis(fluorosulfonyl)imide (FSI)-based electrolyte, which has both higher solubility and diffusivity. Operando acoustics and ex-situ imaging techniques are used to observe the effects and reversibility of precipitation in the PF6 electrolyte system. Lastly, a physics-based model is employed to define saturation-based limiting conditions given the physical electrode thickness, tortuosity, porosity, and electrolyte diffusivity. Figure 1

Early Sensing of Hazardous Volatile Organic Compounds to Avoid Disastrous Li-Ion Battery Thermal Runaway

Worldwide, lithium-ion batteries (LIBs) applications are growing from kWh (electric vehicle) to GWh (grid storage). Along with LIBs proliferation, the complexities in giga factory level battery manufacturing, large-scale storage, system installations and safe DoD operations became significant with enhanced probabilities to mechanical, electrical, or thermal abuse conditions. Thermal runaway,1 a potential hazard leading to battery failure and even fire and explosions, demands innovative solutions for early detection to prevent catastrophic incidents.Purdue University’s Vilas Pol Energy Research (ViPER) research team innovated scalable, cost effective, and energy efficient polymeric sensor2 for the early detection of volatile organic compounds (VOCs) and various gases released before catastrophic thermal runaway through measuring increased impedance in the LIBs. The studied impedimetric chemosensing of VOCs and vented gases coupled with the battery management system (BMS) is capable of early warning through real time data analysis to the driver/operator, public, fire fighters and first responders on expected toxic and combustible gases.For the proof of concept, submicron (∼0.15 μm) thick poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) sensor film was coated on an interdigitated platinum electrode measuring VOCs at 5, 15, and 30 ppm independently, in various combinations and at different temperatures with DC resistance/impedance spectroscopy.3-5 These preliminary research and development activities (TRL 2) demonstrated that the initial generation of VOCs before final thermal runaway of the cells can be tracked in seconds mitigating catastrophic event from occurring by sudden cooling of the entire system or venting the storage area. The obtained detection results will be discussed with the technology that could avoid LIBs thermal runaway in the field environment. References W. Huang, X. Feng, Y. Pan, C. Jin, J. Sun, J. Yao, H. Wang, C. Xu, F. Jiang and M. Ouyang, J. Energy Storage, 2023, 59, 106536.V. G. Pol, P. Kaur, Methods and Apparatus for sensing volatile organic compounds and gases released from electrochemical cells, US Patent App. 18/107,115.P. Kaur, S. Bagchi, V. G. Pol and A. P. Bhondekar, J. Phys. Chem. C, 2023, 127, 8373–8382.P. Kaur, S. Bagchi, D. Gribble, V. G. Pol and A. P. Bhondekar, ACS Sensors, 2022, 7, 674–682.P. Kaur, I. K. Stier, S. Bagchi, V. G. Pol, A. P. Bhondekar, Batteries, 2023, 9, 1–14.

Nanoporous Amorphous Silicon Thin Films Fabricated with Helium Plasma for Lithium Ion Battery Application

Lithium-ion batteries (LIBs) have the advantage of being compact and lightweight, and significant advancement has been made commercially and acadmically in recent several decades. It is essential to develop a new anode material that can replace graphite to further increase capacity, and various materials are being investigated including silicon (Si). Among them, Si is being studied as a candidate for a new anode material because its theoretical capacity per weight is about ten times higher than that of graphite and it is abundant and inexpensive. Among them, thin film approach has achived a great success and good electrochemical performance in terms of specific capacity and cycle life. One of the challenging issues with the thin film approach is that thick films, typically 500 nm, cannot maintain the performance identified in thinner film samples. In this study, we introduce a novel method using helium (He) plasma to form porous Si thin film. Different magnetron sputtering, in the present plasma-assisted method deposit Si atoms on the surface while the surface is exposed to the He plasma. It is shown that plasma assisted method can be another candidate to form nanoporous amourphous Si thin film for high performance LIB application.Silicon thin film was formed in the linear plasma device called Co-NAGDIS. The plasma is produced by a direct current arc discharge using a meander lanthanum hexaboride cathode heated with a Joule current. The magnetic field by two solenoidal coils formed a cylindrical plasma. Helium gas was used for the discharge gas, and the He flux was measured with a reciprocating electrostatic probe. Difference from the magnetron sputtering, which also uses plasma and has been widely used to fabricate Si layer for LIB application, is in the fact that particles (He ions) of high-density plasma, typically ~1018 m-3, are also implanted together with Si atoms on the substrate. Copper (Cu) substrate is equipped to an air-cooled sample stage, of which temperature can be controlled by changing the flow rate of the air. Silicon sputtering plate is installed 1 cm away from the substrate and biased to ~-100 V to induce sputtering. The sputtered Si atoms deposit to the substrate together with the He ions. The deposition time was 90 min for all the samples. The porosities of the two samples shown in this work (Si1 and Si2) was ~0.5, and the thickness was ~1.5 micrometer. The sample tempearture during deposition was 523 K (Si1) and 573 K (Si2).Figure shows the discharge capacities of the two samples (Si1 and Si2). Charging and discharging were repeated with C rate of 0.01C for times 1-3, 0.02C for times 4-6, 0.05C for times 7-9, and 0.1C for times >9. They had an initial capacity of approximately 3000 mAh/g, and they retained higher than 1000 mAh/g even after 20-30 cycles. For Si1, the number of charge-discharge cycles was extended to 250 cycles, and the performance of Si1 gradually decreased but still remained 1800 mAh/g after 100 cycles and ~1200 mAh/g at 250 cycles. The surface was observed by scanning electron microscope (SEM), the surface of Si1 and Si2 was almost flat. From cross section observation by a transmission electron microscope (TEM) after a focus ion beam miiling, it was found that there is no clear evidence of He bubbles in the Si deposition layer, but the layer is mainly composed of 100-200 nm diameter clusters, and the density between the clusters is lower. Thermal desorption spectroscopy (TDS) analysis was performed to analyze the behavior of implanted He atoms in Si layer. It was found that He atoms are implanted to the thin film layer. From the Raman spectroscopy, it was found that amorphous Si was formed at 523 K, but it becomes crystal structure at 573 K. The importance of the amorphous structure is well recognized, and it can be said that Si1 showed better performance than Si2 due to its amorphous structure. In the Figure, evolutions of coulombic efficiency (CE) of Si1 and Si2 is also shown. The CE increases in the initial 5-10 cycles and almost constant after then. The averaged CE after 50 cycles for Si1 and Si2 were 99.51 and 98.72%, respectively. The results showed that the plasma implanting method can be a novel method to form amorphous porous thin film for lithium ion battery. Figure 1

New Insights into the Effect of Cellulose-Based Separators on Electrode-Electrolyte Interface in Lithium Metal Batteries

With a surging demand for electrification, lithium-ion batteries (LIBs) featuring higher energy and power densities have become indispensable. Copious research is being conducted on various components of LIBs to achieve cells with superior performance. Among these components, the separator plays a crucial role as it serves as insulation between the positive and negative electrodes while providing mechanical and thermal stability to the cells, thereby ensuring battery safety. In the pursuit of enhancing separators, a sufficient and controllable porosity and increased electrolyte wettability have gained prominence in separator research for high-performance LIBs, reflected in a large increase in research publications on separator technology in the past decade1.Currently, polyethylene (PE)/polypropylene (PP) membranes, known for their desirable electrochemical stability, have been the favored material for separators. However, these membranes have poor thermal stability, particularly at higher temperatures associated with fast charging rates. This thermal vulnerability can culminate in the decomposition of the separator, introducing a major hazard in the form of electrical shorts that may discharge the battery and lead to battery fires. Thus, separator materials that offer superior safety benefits are needed to ensure safe application of LIBs in next-generation applications2.Among the proposed materials for next-generation separators, there is a notably strong interest in cellulose-based separators (CBS). The primary advantage of cellulose compared to PE/PP membranes is greater thermal stability, as demonstrated by an initial decomposition temperature of 270°C. This greatly increases the safety of the battery since the risk of battery fires stemming from separator decomposition is reduced significantly. Along with increased thermal stability, several reports have shown enhanced energy density, and longevity in LIBs using CBS because of its desirable electrochemical stability, wettability, and water scavenging capability3,4,5.In this work, we study the CBS in a Li-metal battery with inherently higher energy density, thus, intensified challenges. While the majority of reports discuss the advantages of CBS, herein, we present new insights into possible drawbacks of CBS and its suitability for highly concentrated Li-based batteries. We investigated a commercial CBS with Li metal anode and NMC cathode materials. The compatibility and performance of CBS in Li metal-based coin cells (symmetrical and asymmetrical) are studied through electrochemical measurement techniques including cyclic voltammetry (CV), pre- and post-cycling electrochemical impedance spectroscopy (EIS) and cycling test. Similar measurements are carried out on cells with conventional PE/PP separator. Surface and morphological characterizations are conducted on the CBS, Li metal anode, and cathode to provide a more comprehensive view of the CBS interaction with Li metal and NMC cathode. It was observed that while CBS results in a more stable and uniform solid electrolyte interphase (SEI) on Li metal, it is incompetent in impeding Li dendrites. A potential method to reach a clearer understanding of the underlying mechanisms, involving the introduction of oxide coatings to the CBS separator, is explored. It is expected that this study will provide a fundamental understanding of the effects of cellulose on Li metal battery and further clarify its potential for next generation LIBs.