Lithium Electrode Research Articles

Defect-Mediated Formation of Oriented Phase Domains in a Lithium-Ion Insertion Electrode.

The performance and robustness of electrodes are closely related to transformation-induced nanoscale structural heterogeneity during (de)lithiation. As a result, it is critical to understand at atomic scale the origin of such structural heterogeneity and ultimately control the transformation microstructure, which remains a formidable task. Here, by performing in situ studies on a model intercalation electrode material, anatase TiO2, we reveal that defects─both preexisting and as-formed during lithiation─can mediate the local anisotropic volume expansion direction, resulting in the formation of multiple differently oriented phase domains and eventually a network structure within the lithiated matrix. Our results indicate that such a mechanism operated by defects, if properly harnessed, could not only improve lithium transport kinetics but also facilitate strain accommodation and mitigate chemomechanical degradation. These findings provide insights into the connection of defects to the robustness and rate performance of electrodes, which help guide the development of advanced lithium-ion batteries via defect engineering.

Influence of 3D Structural Design on the Electrochemical Performance of Aluminum Metal as Negative Electrode for Li-Ion Batteries.

Aluminum (Al) is one of the most promising active materials for producing next-generation negative electrodes for lithium (Li)-ion batteries. It features low density, high specific capacity, and low working potential, making it ideal for producing energy-dense cells. However, this material loses its electrochemical activity within 100 cycles, making it practically unusable. Several claims in the literature support the idea that a dual degradation mechanism is at play. First, the slow diffusion of Li in the Al matrix causes the electrochemical reactions to be partly irreversible, making the initial capacity of the cell drop. Second, the stress caused by cycling make the active material pulverize and lose activity. Recent work shows that shortening the diffusion path of Li by 3D structuring is an effective way to mitigate the first capacity loss mechanism, while alloying Al with other elements effectively mitigates the second one. In this work, we demonstrate that the benefits of 3D structuring and alloying are cumulative and that a mesh made of an Al-magnesium alloy performs better than both a pure Al foil and a foil of an Al-Mg alloy.

An integrated simulation and experimental study of calendering process in water-based manufacturing of lithium-ion battery graphite electrode

Lithium-ion batteries produced from water-based manufacturing processes are favored for their environmental and economic advantages, while currently sacrificing some technical performance. This paper reports an integrated study on the calendering process of water-based manufacturing of lithium-ion battery graphite electrode, aiming to improve electrochemical performance of the manufactured lithium-ion batteries. The interactive mechanism between the calendering process and the porous microstructure of the produced graphite electrode was systematically investigated. It reveals that the graphite electrode with 40 % of porosity produced under 79,509 N/m calendering force achieves an optimal 333 mAh/g of specific capacity and 91.2 % of capacity retention after 100 cycles.

In Vacuo Scratching Yields Undisturbed Insight into the Bulk of Lithium-Ion Battery Positive Electrode Materials

In Vacuo Scratching Yields Undisturbed Insight into the Bulk of Lithium-Ion Battery Positive Electrode Materials

POSS based poly (zwitterionic liquids) electrolytes with 3D crosslinked networks for lithium metal batteries

Polymer electrolyte is a potential candidate for the next-generation lithium metal batteries. However, its low room temperature ionic conductivity limited its practical application. Here, a novel POSS-based poly (zwitterionic liquids) organic–inorganic hybrid electrolyte with 3D crosslinked networks was proposed for enabling lithium-ion fast transport by photoinitiated radical polymerization of vinyl zwitterionic monomers and acrylate monomers containing rich EO units and POSS. The synergistic effect of unique structures of 3D organic–inorganic hybrids gel electrolytes such as zwitterionic, rich EO segments and POSS cages facilitate Li+ conduction, resulting in high room temperature ionic conductivity (1.03 × 10-3 S cm-1) and a satisfactory Li+ transference number (0.45). The lithium-symmetric batteries assembled with the novel POSS-based poly (zwitterionic liquids) gel hybrid electrolytes can operate continuously at 0.1 mA cm-2 for 2300 h without any obvious short circuit, indicating good interfacial compatibility between the electrolytes and lithium electrodes. The Li/LiFePO4 batteries assembled with the novel POSS-based poly (zwitterionic liquids) gel hybrid electrolytes exhibit long-term stability.

Electrochemical Performance of Deposited LiPON Film/Lithium Electrode in Lithium-Sulfur Batteries.

This paper presents a composed lithium phosphate (LiPON) solid electrolyte interface (SEI) film which was coated on a lithium electrode via an electrodeposit method in a lithium-sulfur battery, and the structure of the product was characterized through infrared spectrum (IR) analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), environment scanning electron microscope (ESEM), etc. Meanwhile, the electrochemical impedance spectrum and the interface stability of the lithium electrode with the LiPON film was analyzed, while the coulomb efficiency and the cycle life of the lithium electrode with the LiPON film in the lithium-sulfur battery were also studied. It was found that this kind of film can effectively inhibit the charge from transferring at the interface between the electrode and the solution, which can produce a more stable interface impedance on the electrode, thereby improving the interface contact with the electrolyte, and effectively improve the discharge performance, cycle life, and the coulomb efficiency of the lithium-sulfur battery. This is of great significance for the further development of solid electrolyte facial mask technology for lithium-sulfur batteries.

A multi-step discharge/charge model of Li[sbnd]O2 batteries coupled with electrolyte decomposition and carbon electrode corrosion reactions

Electrolyte decomposition and electrode corrosion stand as two primary side reactions in lithium‑oxygen (LiO2) batteries during their discharge/charge cycles. In this work, a comprehensive LiO2 battery model combining multi-step lithium peroxide (Li2O2) formation, electrolyte decomposition, and electrode corrosion is proposed. Based on this model, the deposition behaviors and cycling performance of the LiO2 battery under deep discharge/charge cycles are investigated. The stop of discharge is mainly ascribed to the loss of active surface area for the battery using tetraethylene glycol dimethyl ether (TEGDME) electrolyte, while both O2 transport limitation and active surface area loss lead to the discharge termination for battery using dimethyl sulfoxide (DMSO) electrolyte. The incomplete decomposition of Li2O2 and lithium carbonate (Li2CO3) clogs electrode pores, leading to a continuous decline in the discharge capacity of the LiO2 battery. For the TEGDME-based battery, the undecomposed Li2CO3 gradually dominates the deposition with cycles, wherein electrode corrosion becomes the primary source of the undecomposed Li2CO3 after 3 cycles. For the DMSO-based battery, undecomposed Li2O2 is always a dominant trigger for battery discharge capacity degradation, although electrode corrosion remains a key contributor to Li2CO3 generation. Despite the DMSO-based battery exhibiting lower rates of electrolyte decomposition and electrode corrosion, it demonstrates poorer cyclic performance than the TEGDME-based battery due to the generation of more toroidal Li2O2. Moreover, when the charging cut-off voltage is reduced to 4.2 V, discharge capacity diminishes more rapidly due to the increased accumulation of undecomposed Li2O2, despite suppressed Li2CO3 deposition. Finally, the results confirm that thick electrodes lead to deteriorating cycling performance, stemming from increased discharge/charge overpotential and extended discharge/charge times, thus intensifying the side reactions.

Electrophoretically deposited nickel titanate/CNT composite as promising anode for lithium/sodium ion batteries

In this study, we have demonstrated that electrophoretically fabricated NiTiO3 (NTO)/CNT composite is a viable negative electrode for lithium and sodium ion batteries, with favorable electrochemical performance. NTO/CNT exhibited initial discharge capacity of 1032 mAhg−1 and 751 mAhg−1 at 100 mAg−1 with a retained capacity of ∼ 412 mAhg−1 and ∼ 180 mAhg−1 even after 100 cycles against lithium and sodium ion respectively. CNT helps in buffering the volume fluctuations by giving structural stability and enables good cycle life performance. Also such good performance can be ascribed to the porous microstructure, good adherence property with the current collector and uniform active material distribution with carbon black and CNT on the deposited film.

In situ construction of 3D crossing-linked gel polymer electrolyte toward high performance and safety lithium metal batteries

Our study focuses on developing high-performance gel polymer electrolytes (GPEs) tailored for lithium metal batteries (LMBs), harnessing the combined benefits of high conductivity of liquid electrolytes and the enhanced safety of solid electrolytes. To this end, we engineered an in situ polymerized GPE (PMIA- TP) that integrates trifluoroethyl methacrylate (TFMA) and pentaerythritol triacrylate (PETA) monomers within an electrospun poly (m-phthaloyl-m-phenylenediamine) (PMIA) supporting membrane. In addition to high ionic conductivity, high lithium ion transference number, enhanced tensile strength and good thermal stability, the resulting PMIA-TP GPE exhibits satisfactory electrochemical stability against lithium electrodes, enabling long-term and stable lithium plating/stripping in symmetric Li//Li cells, and good rate capability and prolonged cycle life for LiFePO4//Li cells. Further X-ray photoelectron spectroscopy analysis and density functional theory calculations revealed that the electrochemical stability of the PMIA-TP GPE towards lithium metal electrode is due to the formation of a fluorine-rich solid electrolyte interphase (SEI) layer facilitated by reactions involving the –CF3 groups in TFMA, which is beneficial for the effective Li+ transport and lithium dendrite suppression. In summary, our study offers a promising approach to fabricating GPEs that offer high safety and high performance for LMBs.

High-Density, Low-Tortuosity Sulfur Electrodes for High Energy Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have attracted significant attention due to their promising theoretical energy and cost-effectiveness.[1] While recently studies have predominantly focused on increasing sulfur mass loading and utilization rate for high specific energy, there remains a noticeable gap in addressing the intrinsic challenge of improving volumetric energy density.[2] This challenge arises as many Li-S investigations rely on highly porous electrodes.[3] Here, we employ a shear-rolling approach to prepare free-standing electrodes characterized by high density (porosity<15%), low tortuosity, and substantial S content (>70%). The incorporation of a vascular-like porous network, facilitated by a pore soft template, plays a pivotal role in achieving high sulfur utilization (>1000 mAh g-1) in high-loading electrodes (>4 mg cm-2) under lean electrolyte condition (E/S 4 mL g-1). This approach results in an extraordinarily high volumetric energy density (668 Wh L-1 of dry cell) when applied to practical Li–S pouch cells. Our study underscores that realizing high volumetric energy in Li–S cell can be achieved by rationalizing the dense electrode architecture. Furthermore, the shear-rolling approach holds broad applicability for fabricating high-energy electrodes using porous or nanoparticle materials with desirable structures. Details of the progress will be discussed at the conference.

Structural Modification Strategy for Enhancing Electrochemical Performance of Electrodes Under High Current Cycling and First Principle Computational Research for Electrode Materials

Recently, there has been significant interest in advancing lithium-ion battery technology due to its widespread use in various applications. Our research delves into this domain, focusing on enhancing the electrochemical properties of batteries through structural modification of electrode materials. Our work demonstrates the significant enhancements of electrochemical performance under high current cycling using structurally modified electrode materials . In first work, crumpled graphene oxide anode proves to be an effective strategy for enhancing its electrochemical properties, attributed to its advantageous crumpled morphology. This morphology allows for improved electrode stability and easier access for lithium ions, enabling them to interact with its larger specific surface area. In second work, we describe enhanced the drawback of reduced electrochemical performance during high-rate cycles by synthesizing multidimensional LFP-based carbon composite. The lithium ion diffusivity and electrode stability of the prepared composite are significantly improved in charging and discharging cycles by introducing graphene quantum dots alongside CNTs, exhibiting superior electrochemical properties even at high current densities. In third work, density functional theory simulation is employed for demonstrating the enhanced electrochemical properties of prepared electrodes by exploring their properties. Our research provides insights into electrode material design as an effective approach to enhancing the electrochemical properties of lithium-ion batteries.Acknowledgement:This work was supported by the National Research Foundation of Korea (NRF-2021R1A2C1008272). This work was supported by Ministry of Trade, Industry and Energy, KEIT, under the project title"International standard development of evaluation methods for nano-carbon-based high-performance supercapacitors for electric vehicles" (project # 20016144).

Effect of Solid Electrolyte Interphase Heterogeneity on the Lithium Deposition Dynamic: A Phase-Field Approach

Lithium dendrites formation is an inherent drawback in the development of all solid-state lithium batteries technology. These issues remain unsolved due to the multiple and competing troubleshooting during lithium plating and stripping. The inhomogeneous mechanical and chemical properties of the Solid Electrolyte Interphase (SEI) [1] lead to uneven current distribution and unsmooth lithium plating and stripping [2,3,4]. A fine understanding of the relationship between the SEI composition and the dynamic of dendrite growth under polarization is not well established. All computational studies are based on homogeneous SEI on the top of the lithium electrode [5, 6]. The local deformation of the SEI under polarization may lead to several mechanical defect such as cracking and therefore a dendrite nucleation. To link the crack dynamic to the current density, we developed a novel multiphase-field approach in order to probe the first instants of the dendrite formation. Indicative variables are used in order to define dynamics phases of lithium electrode (in black on the figure), electrolyte (green) and two SEI domains (blue and red) and their interaction. This method allows to consider the SEI as a multi-domains object, where each region has its own (chemical, mechanical and ion transport) properties. Our results show that a smaller current density result in homogeneous deposition (top row on the figure), where a high current leads to a fracture of the SEI and a dendrite growth (bottom row). We highlighted the influence of SEI properties such as the thickness, the ratio between SEI domains or the surface tension on the deposition dynamic.On the left of the figure, the simulation box constituted of lithium (in black color) in contact with a solid electrolyte interphase constituted of a dense (blue) and porous (red) SEI, and electrolyte (green). The dynamic evolution of lithium and SEI, under low and high current density 0.12 and 12 mA/cm² are reported on top and bottom figures respectively.

Lithium-ion battery high performance cathode electrode based on LiFePO4 and thermal sensitive microspheres with thermal shutdown properties

The critical issue of thermal runaway events in lithium-ion batteries (LIBs) is recognized as a primary cause of battery-related accidents. Despite ongoing efforts to enhance LIB safety, challenges persist due to varying chemical compositions, states of charge, and conditions of use across different batteries. To advance battery safety and considering cost and practicality, this research introduces a novel cathode material with thermal shutdown characteristics. Incorporating thermoplastic microspheres into the cathode matrix does not compromise the cathode's structural integrity, but leads to ionic conductivity value reduction, and a consequent reduction of battery performance for the larger microsphere concentrations of 5.0 wt% and 7.5 wt%. On the other hand, the samples demonstrate a thermal shutdown behaviour, triggered by the volumetric expansion of the microspheres, effectively ceasing electrical and ionic conduction, thereby preventing thermal runaway. The cathode with low microsphere concentration, 2.5 wt% of microspheres, outperforms (155 mAh·g−1, at C/8-rate) room temperature battery performance with respect to the conventional cathode and also exhibits thermal shutdown behaviour at 90 °C. The research highlights the potential of integrating expandable microspheres into cathodes for the development of safer batteries, offering a scalable and cost-effective solution compatible with existing battery technologies.

Compliant Solid Polymer Electrolytes (SPEs) for Enhanced Anode-Electrolyte Interfacial Stability in All-Solid-State Lithium-Metal Batteries (LMBs).

Practical application of high energy density lithium-metal batteries (LMBs) has remained elusive over the last several decades due to their unstable and dendritic electrodeposition behavior. Solid polymer electrolytes (SPEs) with sufficient elastic modulus have been shown to attenuate dendrite growth and extend cycle life. Among different polymer architectures, network SPEs have demonstrated promising overall performance in cells using lithium metal anodes. However, fine-tuning network structures to attain adequate lithium electrode interfacial contact and stable electrodeposition behavior at extended cycling remains a challenge. In this work, we designed a series of comb-chain cross-linker-based network SPEs with tunable compliance by introducing free dangling chains into the SPE network. These dangling chains were used to tune the SPE ionic conductivity, ductility, and compliance. Our results demonstrate that increasing network compliance and ductility improves anode-electrolyte interfacial adhesion and reduces voltage hysteresis. SPEs with 56.3 wt % free dangling chain content showed a high Coulombic efficiency of 93.4% and a symmetric cell cycle life 1.9× that of SPEs without free chains. Additionally, the improved anode compliance of these SPEs led to reduced anode-electrolyte interfacial resistance growth and greater capacity retention at 92.8% when cycled at 1C in Li|SPE|LiFePO4 half cells for 275 cycles.

Operando Raman observation of lithium-ion battery graphite composite electrodes with various densities and thicknesses

Understanding the mechanisms of inhomogeneous charging and discharging reactions in an electrode is critical to improving the rate capability of lithium-ion batteries. Various methods have been developed to observe the distribution of electrode structure or lithium ions within an electrode; however, most of these methods require large-scale equipment or entail complex procedures. To simplify reaction distribution measurements within electrodes, this study developed specially designed cells and conducted operando observations of reaction distribution in graphite composite electrodes using Raman spectroscopy. Behaviors on both the electrolyte and current collector sides of the electrodes were compared, and electrodes of various densities and thicknesses were examined. For electrodes with low density, the changes in graphite structure were almost simultaneous on the electrolyte and current collector sides and were hardly dependent on the electrode thickness. In contrast, the changes in electrode structure with increased density were dependent on their thickness. This implies that the ion transportation length is responsible for the reaction distribution in the electrodes when ion channels connecting the current collector and electrolyte sides decrease owing to the increased electrode density. The simple method developed in this study is expected to further contribute to the understanding of the distribution of reactions within graphite composite electrodes.

Electrospun Co-Ni mixed multiple oxidation states heterostructure for high-performance Li-ion battery

With the increasing prevalence of mobile electronic devices, electric vehicles, and other technological advancements, there is a growing demand for higher-capacity Lithium-ion batteries (LIBs). Metal-organic frameworks (MOFs) have been actively researched in recent years due to their numerous advantages. However, the irreversible collapse during lithium-ion interaction hampers MOFs’ electrochemical stability. This study employs a direct precipitation method to synthesize uniformly shaped MOF materials, followed by carbon coating using electrospinning techniques, and ultimately, derivatives of MOF materials are produced through annealing. Thanks to this innovative material design process, exceptional performance is observed in this material as a lithium-negative electrode. After 1000 cycles at a high current density of 1 A g−1, its reversible capacity stabilizes at 1318 mAh g−1. Moreover, this negative electrode material exhibits exceptional rate performance at various current densities. The Co3O4/NiO@NCNFs electrode demonstrates enhanced charge storage capacity due to the synergistic effects of diffusion and capacitance control processes. Additionally, this material exhibits characteristics of low impedance and high lithium-ion diffusion rate. This study presents a novel method for manufacturing lithium-ion battery negative electrode materials by integrating MOF materials with electrospinning technology.

A Facile Chemical Reduction Approach of Li–Sn Modified Li Anode for Dendrite Suppression

Lithium dendrites are among the most significant threats associated with the practical application of lithium metal anode in lithium batteries. Lithium dendrites are caused by the slow Li‐ion diffusivity in the bulk lithium, which results in a non‐uniform electric field‐cum‐uneven Li plating/stripping at the electrode/electrolyte interface over prolonged cycling. Herein, a facile chemical reduction method is utilized to construct a Li‐ion diffusive Li–Sn protective layer on the electrolyte‐exposed surface of lithium metal to overcome the aforementioned challenge. A systematic study on the SnCl4 precursor concentration variation demonstrated that 25 mM SnCl4 concentration is the most effective and displays a cumulative areal capacity beyond 700 mAh cm−2 at 1 mA cm−2 for 1 h. Moreover, it exhibits superior cumulative capacities than bare Li metal at higher current densities of 2 and 3 mA cm−2. In situ optical microscopy reveals more uniform lithium deposition on the Li–Sn‐modified electrode, while mossy and dendritic lithium growth is observed on the bare lithium electrode. Full cells fabricated with Li–Sn modified anode and NMC532 cathode exhibited 83% capacity retention after 150 cycles, outperforming bare Li‐containing cells, which shows a catastrophic decay post 100 cycles, illustrating the propensity for safer Li metal batteries with Li–Sn modified anode.

Optimized NMC622 electrodes with a high content of the active material: A comprehensive study

The composition of lithium-ion battery positive electrodes, incorporating an active material, conductive carbon additives, and a binder, fundamentally influences the electrode physical and electrochemical characteristics. In this study, the properties of positive electrodes with a high amount of an active material (LiNi0.6Mn0.2Co0.2O2 98 wt-%), were tested with different ratios of carbon nanotubes (CNTs) and carbon black (CB) additives, along with varying amounts of a PVDF binder. Consequently, the electrode rate capability improves with the increase of CNTs up to 30 wt-% in the total conductive carbon share and increasing the binder amount to 1 wt-%, attributed to the optimal balance of inactive material amount. The optimal composition is determined to be 98 wt-% NMC622, 1 wt-% PVDF, and 1 wt-% total conductive carbons, out of which CNT shares accounting for 30 wt-%. Furthermore, this study continues by comparing the optimal composition with the reference electrode (CNT-free) to assess the impact of CNTs on electrochemical performance. With CNTs present, the electrode attains higher energy density and specific capacity owing to uniform conductive network. Operando XRD and dilatometry experiments also reveal that CNTs reduce irreversible height change during cycling and minimize anisotropic lattice changes, thus enhancing capacity retention.

Insight of transport properties of glassy solid electrolytes for energy storage applications

The goal of developing battery systems has attracted researchers' attention for about 30 years, almost since the development of primary electrochemical systems with a lithium anode. To realize the benefits of lithium ion batteries (LIBs) and lithium metal anode batteries, several important issues need to be addressed. The use of liquid non-aqueous electrolytes based on aprotic solvents in lithium battery systems certainly offers advantages over traditional battery systems. However, due to the relatively low evaporation temperatures and high flammability of solvents, liquid electrolytes significantly limit the operating range of battery systems in the high-temperature range. Special measures are required to ensure the safe operation of a lithium-ion battery system. The use of inorganic solid electrolytes (SEs) is one of the most promising directions for improving lithium-ion and solid-state battery systems. The use of SEs will enable the safe cycling of battery systems with both lithium electrodes and intercalation anodes, significantly extend the temperature range of battery operation towards high temperatures and enable the creation of battery systems of new sizes and designs. The development of new solid oxide salt materials and technologies to produce battery systems with electrolytes based on them is an urgent task to solve the above problems.

Sulfur Encapsulation into Carbon Nanospheres as an Effective Technique to Limit Sulfide Dissolution and Extend the Cycle Life of Lithium–Sulfur Batteries

Sulfur Encapsulation into Carbon Nanospheres as an Effective Technique to Limit Sulfide Dissolution and Extend the Cycle Life of Lithium–Sulfur Batteries