Stability Of Lithium-ion Batteries Research Articles

Propylene carbonate synthesis routes using CO2: DFT and thermodynamic analysis

Propylene carbonate (PC) is utilized to improve performance and stability in lithium-ion batteries as an electrolyte component and as a high-performance solvent in paints, varnishes, and adhesives. It is a versatile chemical used in many different industries. It also functions as a plasticizer in polymers and a solvent in pharmaceutical and cosmetic formulations. In the current work, chemical equilibrium analyses of a number of potential processes involved in the synthesis of PC were conducted. To examine the thermodynamic viability of all five approaches, the fluctuation of ΔGmo with temperature for the key processes of PC synthesis was investigated in a specific temperature range of 25 °C-180 °C and at 1 bar and 60 bar pressures. The heat capacity values were estimated using the Rozicka-Domalski method. Benson Group-Increment Theory (BGIT) was used to evaluate the unknown ΔfH for a molecule. By examining the impact of temperature (25 °C-180 °C) and pressure (0–100 bars) on chemical equilibrium constant and equilibrium conversion of reactants, the main reactions of PC synthesis pathways were compared. It was discovered that the one-pot synthesis route and the o-chloropropanol and CO2 approach were superior. The DFT calculations were performed to study the energy changes taking place to convert propylene, glycerol, and propylene glycol (PG) into PC. Both thermodynamic and DFT calculations proved that the PG and urea route is the least favorable for synthesizing PC.

Advancements in Alumina Ultrathin Coatings for Enhanced Electrochemical Performance of Ni-Rich NMC811 Thick Electrodes

Lithium-ion batteries, renowned for their high energy density, face a significant challenge in the development of stable, high-performing, and cost-effective cathode materials. Ni-rich cathodes, while promising, suffer from instability issues such as microcracking, high surface reactivity, phase transformation, and thermal runaway. This study introduces a breakthrough: the application of an alumina (Al2O3) ultrathin coating to enhance the stability of Ni-rich thick electrodes. The uniform distribution of the Al2O3 coating across the electrode acts as a protective barrier, effectively reducing oxygen lattice release and microcracking. Our findings reveal that this atomic layer deposition (ALD) technique markedly boosts the cycling stability of the electrodes. Coated electrodes maintained high specific capacity after long cycling, significantly outperforming uncoated electrodes, which retained only small capacity. This innovative approach shows great potential for the development of high-performance and stable lithium-ion batteries. Figure 1

Grain Analysis of NCM Cathode Materials by ASTAR Technique and Its Effect on Battery Performance

Lithium-ion batteries (LIBs) are one of the most promising energy storage systems for portable electronic devices, electric vehicles, and renewable energy systems. Among the various cathode materials for LIBs, nickel cobalt manganese (NCM) oxide has attracted considerable attention due to its high specific capacity, good cycling stability, and appropriate cost for commercialization. However, Ni-rich NCM (Ni >80%) showed poor cyclability and huge gas evolution because of surface instability.Single crystal NCM has been suggested as a solution to these issues due to its excellent properties. However, it is difficult to quantify the degree of single crystallinity because it is so far subjective. In this study, we employed ASTAR technique (transmission electron microscopy combined with electron backscatter diffraction) to investigate the microstructural features of NCM cathode materials. Our ASTAR analysis showed that NCM cathode materials consist of complex grain and grain boundary structures with varying orientations and sizes. By analyzing the grain size and its morphology, we were able to define the single crystallinity of NCM cathode materials, including the poly NCM and single crystal NCM particles.Furthermore, we found that the grain size and its distribution significantly affects the battery performance and lifespan of NCM cathode materials. Specifically, the poly NCM particles exhibited a larger grain boundary and surface area compared to the single crystal NCM particles. The poly NCM particles also showed a faster DC-IR increase and a shorter lifespan than the single crystal NCM particles, indicating that the grain size has a critical influence on the battery performance and lifespan of NCM cathode materials.Our results provide insights into the design and optimization of NCM cathode materials for next-generation LIBs. By controlling the grain size and its distribution of NCM cathode materials, it is possible to enhance the battery performance and lifespan. Therefore, our study highlights the importance of understanding the microstructural features of NCM cathode materials for developing high-performance and stable LIBs.

Lamellar sulfonated acid polymer-initiated in situ construction of robust LiF-rich SEI enabling superior charge transport for ultrastable and fast charging silicon anodes

The extreme volume expansion of the silicon (Si) anodes during repeated cycles seriously induces undesirable interfacial side reactions, forming an unstable solid electrolyte interphase (SEI) that degrades the electrode integrity and cycle stability in lithium-ion batteries, limiting their practical applications. Despite considerable efforts to stabilize the SEI through surface modification, challenges persist in the development of high-performance Si anodes that effectively regulate intrinsic SEI properties and simultaneously facilitate electron/ion transport. Here, a highly conductive and organic electrolyte-compatible lamellar p-toluenesulfonic acid-doped polyaniline (pTAP) layer is proposed for constructing a robust artificial SEI on Si nanoparticles to achieve fast charging, long-term cycle lifespan and high areal capacity. The spatially uniform pTAP layer, formed through a facile direct-encapsulation approach assisted by enriched hydrogen bonding, contributes to the effective formation of in situ SEI with an even distribution of the LiF-rich phase in its interlamination spaces. Furthermore, the integrated artificial SEI facilitates isotropic ion/electron transport, increased robustness, and effectively dissipates stress from volume changes. Consequently, a notably high rate performance of 570 mA h g−1, even at a substantially high current density of 10 A g−1, is achieved with excellent cyclic stability by showing a superior capacity over 1430 mA h g−1 at 1 A g−1 after 250 cycles and a high areal capacity of ca. 2 mA h cm−2 at 0.5 C in a full cell system. This study demonstrates that the rational design of conductive polymers with SEI modulation for surface protection has great potential for use in high-energy-density Si anodes.

N-Containing Porous Carbon-Based MnO Composites as Anode with High Capacity and Stability for Lithium-Ion Batteries.

MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest for being low-cost and rich in functional groups and hetero atoms. This work designs porous N-containing MnO composites based on the chemical-activated tremella using a self-templated method. The tremella, after activation, could offer more active sites for carbon to coordinate with the Mn ions. And the as-prepared composites could also inherit the special porous nanostructures of the tremella, which is beneficial for Li+ transfer. Moreover, the pyrrolic/pyridinic N from the tremella can further improve the conductivity and the electrolyte wettability of the composites. Finally, the composites show a high reversible specific capacity of 1000 mAh g-1 with 98% capacity retention after 200 cycles at 100 mA g-1. They also displayed excellent long-cycle performance with 99% capacity retention (relative to the capacity second cycle) after long 1000 cycles under high current density, which is higher than in most reported transition metal oxide anodes. Above all, this study put forward an efficient and convenient strategy based on the low-cost biomass to construct N-containing porous composite anodes with a fast Li+ diffusion rate, high electronic conductivity, and outstanding structure stability.

Design of double layer cathode electrode for improving the safety and stability of lithium-ion batteries

LiNi0.8Co0.1Mn0.1O2 (NCM) is a widely used cathode material for lithium-ion batteries (LIBs). However, the poor cycle performance and safety issue remains a huge challenge for its practical applications. Here we show a simple double layer strategy to improve the electrochemical characteristics and safety performance. NCM was coated by LiFePO4 (LFP), a safe cathode material with long cycle stability, exhibited more excellent cycling stability and similar rate properties at room temperature (called NCM/LFP). Under 45 ℃, the NCM/LFP (6:1)||graphite pouch cell shows excellent 83% capacity retention after 600 cycles at 1C, which compared to the sharp attenuation of pristine NCM. Furthermore, NCM/LFP (6:1)||graphite cell could pass the nail penetration tests and the thermal runaway temperature (TTR) delayed by 193℃, which proved the double layer design has better safety performance. The current work might pave an avenue for cathode materials, as a sustainable solution to high energy density LIBs for applications.

Invoking Interfacial Engineering Boosts Structural Stability Empowering Exceptional Cyclability of Ni-Rich Cathode.

The cycling stability of LiNi0.8Co0.1Mn0.1O2 under high voltages is hindered by the occurrence of hybrid anion- and cation-redox processes, leading to oxygen escape and uncontrolled phase collapse. In this study, an interfacial engineering strategy involving a straightforward mechanical ball milling and low-temperature calcination, employing a Se-doped and FeSe2&Fe2O3-modified approach is proposed to design a stable Ni-rich cathode. Se2- are selectively adsorbed within oxygen vacancies to form O─TM─Se bond, effectively stabilizing lattice oxygen, and preventing structural distortion. Simultaneously, the Se-NCM811//FeSe2//Fe2O3 self-assembled electric field is activated, improving interfacial charge transfer and coupling. Furthermore, FeSe2 accelerates Li+ diffusion and reacts with oxygen to form Fe2O3 and SeO2. The Fe2O3 coating mitigates hydrofluoric acid erosion and acts as an electrostatic shield layer, limiting the outward migration of oxygen anions. Impressively, the modified materials exhibit significantly improved electrochemical performance, with a capacity retention of 79.7% after 500 cycles at 1C under 4.5V. Furthermore, it provides an extraordinary capacity retention of 94.6% in 3-4.25V after 550 cycles in pouch-type full battery. This dual-modification approach demonstrates its feasibility and opens new perspective for the development of stable lithium-ion batteries operating at high voltages.

Synergistic Regulation of Built-In Electric Field and Interface Effect to Enhance the Reaction Kinetics and Stability of Lithium-Ion Batteries

Synergistic Regulation of Built-In Electric Field and Interface Effect to Enhance the Reaction Kinetics and Stability of Lithium-Ion Batteries

Preparation of lithium ferromanganese phosphate by non-stoichiometric strategy

LixFexMn1-xPO4 exhibits low production costs, environmental friendliness, high energy density, thermal stability, and cycling stability in lithium-ion batteries (LIBs), presenting broad application prospects. Furthermore, studies have shown that adopting a non-stoichiometric ratio strategy can reduce particle size, decrease anti-site defects, and generate a conductive impurity phase on the material surface. This leads to an enhancement in the electrochemical performance of the material, making it an effective approach to achieving high-performance olivine-type cathode materials. In this study, three materials were successfully prepared using the solid-phase method: Li1.05Fe0.5Mn0.475PO4/C, Li1.05Fe0.5Mn0.5PO4/C, and Li1.05Fe0.475Mn0.5PO4/C. The physical properties of the materials were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The electrochemical performance including specific capacity, rate performance, and cycling performance were studied through charge-discharge tests, with Li1.05Fe0.5Mn0.475PO4/C exhibiting the best specific capacity at all rates. At rates of 0.1 C, 0.5 C, 1 C, 2 C, and 5 C, its average reversible specific capacities were 143.5, 129.5, 122.1, 112.8, and 97.3 mAh·g−1, respectively. Furthermore, differences in electrochemical performance of three materials were discussed in detail through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).

Designing high-chaos mixed-salt electrolytes for enhancing graphite-electrolyte interfacial stability in lithium-ion batteries

The interfacial stability between graphite anodes and electrolytes is crucial for the electrochemical performance of lithium-ion batteries, particularly at low temperatures. This study investigates the effect of incorporating four common Solid-Electrolyte Interphase (SEI) components—LiF, LiNO3, Li2O, and Li2CO3—directly into two types of commercial electrolytes: carbonate-based (1.0 M LiPF6-EC/DMC, LP30) and ether-based (1 M LiTFSI-DOL/DME+2 % LiNO3, LDD) both with 5 % FEC (v/v) to create high-chaos mixed-salt electrolytes (LP30-FEC-4S and LDD-FEC-4S). Our findings show that Li/graphite cells exhibit significantly enhanced rate performance in both LP30-FEC-4S and LDD-FEC-4S electrolytes, compared to commercial LP30 and LP57 electrolytes. LiFePO4/graphite full cells using LP30-FEC-4S and LDD-FEC-4S electrolytes also showed excellent electrochemical performance (124.73 mAh g−1 and 119.21 mAh g−1 specific capacities at 0.5C). Remarkably, stable SEIs form rapidly on the graphite anode surfaces in the designed electrolytes even at low temperatures of −10 °C. Moreover, we demonstrate that the Li+ solvation structure is fundamental in determining the overall electrochemical performance. This study suggests that enhancing the mixing entropy of the system by adding multiple lithium salts to a commercial electrolyte is an effective and cost-efficient strategy for improving graphite-electrolyte compatibility.

Interfacial modulation of hollow ZnS-SnS2 microboxs by Ti3C2Tx MXene to construct three-dimensional hybrid anodes for lithium-ion batteries with ultra high stability at low temperature

Metal sulfides exhibit obvious volume expansion due to the inherent poor conductivity and large temperature fluctuations, leading to reduced storage capacity. Herein, an electrostatic self-assembly strategy was proposed to fabricate a three-dimensional (3D) polyaniline (PANI) encapsulated hollow ZnS-SnS2 (H-ZSS) heterojunction confined on Ti3C2Tx MXene nanosheets (H-ZnS-SnS2@MXene@PANI, denoted as H-ZSSMP), which exhibits remarkable reversible capacity and cyclic stability (520.3 mAh/g at 2 A/g after 1000 cycles) at room temperature. Additionally, specific capacity can stabilized at 362.5 mAh/g for 250 cycles at −20 °C. A full cell with the configuration of H-ZSSMP//lithium iron phosphate (LiFePO4) can retain a satisfactory reversible capacity of 424.7 mAh/g after 100 cycles at 0.1 C. Theory calculations confirm heterogeneous interface can accelerate the transfer of ions through the interfacial regulation effect of MXene on H-ZSS. Our work provides a simple strategy to improve the capacity and stability of lithium-ion batteries (LIBs), as well as the new applications of MXene and bimetallic sulfides as anode materials, which will facilitate the development of MXene based composites for energy storage.

Stable surface lattice for prolonged cycle life of single-crystal lithium-rich layered oxide cathodes

Lithium-rich layered oxides (LLOs) have garnered significant attention due to their outstanding capacity. However, the severe capacity fading resulting from lattice deterioration initiated at the surface constrains the further advancement of LLOs. Here, we present a method to stabilize the surface lattice to enhance the capacity stability of LLOs. Specifically, we have engineered a nanometer-thin Gd-doped NiO rock-salt epitaxial layer on the surface of single-crystal LLOs, along with an atomic-level thickness LiGdO2coating layer. The dual-nanolayer protection strategy has successfully stabilized the surface structure of LLOs and suppressed electrode–electrolyte interface side reactions. As a result, the modified sample achieves a capacity retention rate of 93.4% after 500 cycles at 1C and 94.2% after 200 cycles at 0.2C. Our study underscores the importance of surface structure in achieving high cyclic stability in LLOs and provides an important approach for designing stable lithium-ion battery cathode materials.

A graded structure of silicon/carbon composite powder for highly stable lithium ion battery anode

Silicon has much higher theoretical specific capacity than traditional graphite materials (3579 mAh g−1vs. Graphite: 372mAh g−1). However huge volumetric expansion (∼300%) of silicon seriously reduces its cyclic stability as anode in lithium-ion batteries. Though reduce the size of silicon based composites to nanoscale and tuning their porosity have been extensively studied, above strategies reduce the vibration density of the anode material unsurprisingly, which is not conducive to the advantage of high volumetric capacity anode. In this work, we design a unique graded silicon/carbon powder to maintain excellent energy storage performance at high vibration density. The composite of graded structure is constructed by first particles and second particles. The construction strategy is proved to be adoptable to achieve cost effective production of high performance silicon/carbon composite anode for development of advanced lithium-ion battery. Under the premise of industrial powder materials’ production technologies, a graded structure silicon/carbon composite with optimized synthetic condition shows high-reversible capacity of 827.4 mAh g−1 at 200 mAh g−1 (equal to 1464.5 Ah L−1) and it capacity remains at 715.0 mAh g−1 after 800 cycles, with a capacity retention rate of 86.37%, which shows high cycle life.

In-situ surface growth strategy to synthesize MXene@graphdiyne heterostructure for achieving high capacity and desirable stability in lithium-ion batteries

Two-dimensional (2D) heterostructured electrodes, combining graphdiyne (GDY) and MXenes, have exhibited substantial promise in augmenting the mobility of both ionic and electron movement. However, the widespread advancement and industrial utilization have been impeded by intricate manufacturing procedures and insufficient stability. This study introduces a more streamlined, in-situ growth approach for preparing MXene@GDY electrodes, presenting a novel heterostructure. The method simplifies the manufacturing process while enhancing the specific capacity of the electrode and the more stable cycle life of lithium-ion batteries (LIBs). The resulting electrode exhibited an impressive initial specific capacity of 464.4 mA h g−1, maintaining a high capacity of 492.9 mA h g−1 after 100 cycles at 100 mA current density. More importantly, after 1200 cycles, MXene@GDY showed a capacity of 340.7 mA h g−1, significantly outperforming pure MXene, which only reached 122.3 mA h g−1 at a current density of 1.0 A g−1. The proposed in-situ construction of heterojunction on the MXene surface has demonstrated immense potential for designing high-performance electrode materials which are applicable to LIBs.

Improving LiFePO4 cathode stability in lithium-ion batteries by hybridizing activated tannic with PEDOT:PSS binders

The conventional binder polyvinylidene fluoride (PVDF) exhibits substantial polarization resistance at high magnification because of its inertness to Li+ and electrons. In addition, 1-methyl-2-pyrrolidinone (NMP) solvents are toxic, expensive, and environmentally harmful. In this study, we enhanced the poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) binder by incorporating varying ratios of tannic acid (TA) to develop a water-soluble TA-PEDOT:PSS (TAPE) binder. TAPE1,1 with a TA to PEDOT:PSS ratio of 1:1, designated as TAPE1,1, exhibited high tensile strength (7.55 N/m), low impedance (61 Ω), remarkable cycling stability of 121 mAh g−1 (retaining 83.6 % capacity over 1000 cycles), and excellent rate performance (95 mAh g−1 at a 10C rate). Consequently, this study provides valuable insights into the design of high-performance lithium batteries.

Bacterial cellulose-derived carbon as a self-supported and flexible anode for stable-performance lithium-ion batteries

Lithium-ion batteries (LIBs) have been a breakthrough in the arena of energy storage devices since their inception. Earlier the slurry-coated electrodes are used for the development of LIBs. However, the slurry-coated electrode includes electrochemically inactive species (such as current collector, binder, and carbon additive) which decreases the energy density of the device. Therefore, the research community extensively explores self-supported and flexible electrodes for various electrochemical devices because of their lower electrochemical inactive species. This work reports the usage of sustainable bacterial cellulose as a precursor to derive a self-supported anode for stable lithium-ion batteries. Detailed electrochemical and physicochemical properties were evaluated to understand the efficacy of the self-supported anode. Benefitting from the porous morphology, interconnected nanofibrous assembly, and efficient graphitic domain in carbonized bacterial cellulose the lithium-ion battery delivers an impressive electrochemical performance. Notably, lithium-ion cells with the anode delivered a capacity of 548 mAh/g at 0.05 A/g with shallow irreversible capacity loss (coulombic efficiency of the first cycle is 90%). The cell maintains a capacity of 198 mAh/g at an extremely high current of 2 A/g and retains 82 % of capacity after 1000 cycles at 0.5 A/g. This work paves the way to create a self-supported and flexible electrode with a simple and scalable approach.

Film Thickness Effect in Restructuring NiO into LiNiO2 Anode for Highly Stable Lithium-Ion Batteries

The long-term stability of energy-storage devices for green energy has received significant attention. Lithium-ion batteries (LIBs) based on materials such as metal oxides, Si, Sb, and Sn have shown superior energy density and stability owing to their intrinsic properties and the support of conductive carbon, graphene, or graphene oxides. Abnormal capacities have been recorded for some transition metal oxides, such as NiO, Fe2O3, and MnO/Mn3O4. Recently, the restructuring of NiO into LiNiO2 anode materials has yielded an ultrastable anode for LIBs. Herein, the effect of the thin film thickness on the restructuring of the NiO anode was investigated. Different electrode thicknesses required different numbers of cycles for restructuring, resulting in significant changes in the reconstituted cells. NiO thicknesses greater than 39 μm reduced the capacity to 570 mAh g−1. The results revealed the limitation of the layered thickness owing to the low diffusion efficiency of Li ions in the thick layers, resulting in non-uniformity of the restructured LiNiO2. The NiO anode with a thickness of approximately 20 μm required only 220 cycles to be restructured at 0.5 A g−1, while maintaining a high-rate performance for over 500 cycles at 1.0 A g−1, and a high capacity of 1000 mAh g−1.

Embedding silicon nanoparticle in porous carbon fiber for highly stable lithium-ion battery anode

Silicon is considered as one of the best anode material candidates for future lithium-ion battery. The composite engineering of silicon/carbon matrix is of great importance to prevent the silicon volume change. Traditional method of carbon coating although provide mechanical support but the ion transport is blocked by carbons. Herein, we developed a novel nanoporous carbon matrix synthesized by polymer template. The silicon/carbon nanoporous fiber anode shows high stability and high-rate performance thanks to the strong binding and robust porous structure between silicon nanoparticles and carbon matrix. The silicon/carbon nanoporous fiber anode provides high capacity of 992 mAh/g after 200 cycles at 1C rate and stable cycle retention of 84.4% after 200 cycles at 2C rate, and also shows impressive rate capacity retention of 68.2% at 2C compared with 34.5% retention of bare silicon anode.

Fine-Tuning Intrinsic and Doped Hydrogenated Amorphous Silicon Thin-Film Anodes Deposited by PECVD to Enhance Capacity and Stability in Lithium-Ion Batteries.

Silicon is a promising alternative to graphite as an anode material in lithium-ion batteries, thanks to its high theoretical lithium storage capacity. Despite these high expectations, silicon anodes still face significant challenges, such as premature battery failure caused by huge volume changes during charge-discharge processes. To solve this drawback, using amorphous silicon as a thin film offers several advantages: its amorphous nature allows for better stress mitigation and it can be directly grown on current collectors for material savings and improved Li-ion diffusion. Furthermore, its conductivity is easily increased through doping during its growth. In this work, we focused on a comprehensive study of the influence of both electrical and structural properties of intrinsic and doped hydrogenated amorphous silicon (aSi:H) thin-film anodes on the specific capacity and stability of lithium-ion batteries. This study allows us to establish that hydrogen distribution in the aSi:H material plays a pivotal role in enhancing battery capacity and longevity, possibly masking the significance of the conductivity in the case of doped electrodes. Our findings show that we were able to achieve high initial specific capacities (3070 mAhg-1 at the 10th cycle), which can be retained at values higher than those of graphite for a significant number of cycles (>120 cycles), depending on the structural properties of the aSi:H films. To our knowledge, this is the first comprehensive study of the influence of these properties of thin films with different doping levels and hydrogen distributions on their optimization and use as anodes in lithium-ion batteries.

Boosting LiMn2O4 Diffusion Coefficients and Stability via Fe/Mg Doping and MWCNT Synergistically Modulating Microstructure

The dissolution of manganese and its deposition on the anode surface cause poor cycling stability in lithium-ion batteries. To alleviate these issues, this study probes the electrochemical activity of highly crystalline and cation-adjusted lithium manganese oxide (LMO) carbon spinel composite obtained via a modified sol-gel synthesis procedure. The pristine LMO cathode was functionalized with a Fe and Mg alloy and fused with purified multiwalled carbon nanotubes (MWCNTs) to form a catalytically stabilized LiMn1.98Fe0.01Mg0.01O4/MWCNT (LMO-FeMg/MWCNT) framework. High-resolution SEM analysis showed well-dispersed particles in the nanometer size range. The electrochemical characteristics of the novel composite materials yielded favourable electrochemical results with diffusion coefficients of 1.91 × 10−9 cm2·s−1 and 5.83 × 10−10 cm2·s−1 for LMO-FeMg and LMO-FeMg/MWCNT, respectively. This improvement was supported by impedance studies which showed a considerable Rct reduction of 0.27 Ω and 0.71 Ω. The cation stabilized system outperformed the pristine LMO material with specific capacities around 145 mAh·g−1, due to an enhancement in electrochemical activity and structural stability.