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At least 541 records · Page 30

Battery aging mode identification across NMC compositions and designs using machine learning

A comprehensive understanding of lithium-ion battery (LiB) lifespan is the key to designing durable batteries and optimizing use protocols. Although battery lifetime prediction methods are flourishing, diagnosis of the root causes of aging and degradation have not yet been well developed nor studied for a broad mixture of designs and use cases. Here, we create a machine-learning (ML)-based framework that distinguishes aging modes using multiple electrochemical signatures recorded cycle-by-cycle. The predominant aging behaviors include a combination of loss of active materials in cathode (LAMPE) and a loss of Li inventory (LLI) in Li plating or solid electrolyte interphase (SEI) formation, manifested from 44 batteries representing two cathode chemistries, two electrode loadings, and five charging rates. Here, the aging mode classification accuracy is 86% using features within the first 50 cycles and increases to 88% beyond 225 cycles. The same features can quantify the percentage of end-of-life LAMPE with only 4.3% of error.

25 ENERGY STORAGE↗

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

In response to the growing demand for lithium-ion batteries (LIBs), we demonstrate a solvent-free manufacturing technology that can avoid toxic organic solvents and form unique electrode structures to overcome the bottlenecks in low costs and fast charging. The lower tortuosity achieved by the open pores in the dry-printed (DP) electrode allows for a shorter Li+ diffusion pathway, which leads to better rate performance. The DP pouch cells exhibit higher capacity retention of 78% and 69% at 3C and 4C, respectively, compared with 67% and 52% for the slurry cast (SL) cells at the same rates. Moreover, the coating layer on the surface of active materials prevents the excess side reaction between active materials and electrolytes, which prolongs the cycle life of the DP cells. This manufacturing process is a roll-to-roll system with immense potential to be scaled up, providing a more efficient and economical way for battery manufacturing.

36 MATERIALS SCIENCE↗

Evolution of the Rate-Limiting step: From Thin Film to Thick Ni-rich Cathodes

Ni-rich NMC (LiNixMnyCo1-x-yO2, x = 0.6) has the attributes of high specific capacity (greater than 180 mAh g-1), high operating voltage (ca. 3.8 V) and low cost, which is therefore deemed as one of the most promising cathode candidates for next-generation high-energy Li-ion batteries (LIBs). However, challenges exist before the large-scale commercialization of Ni-rich cathode such as gas generation, capacity degradation especially at high rate or elevated temperatures. From thin film to densely pack high loading cathode, this work investigates the rate-limiting steps in Ni-rich cathodes e.g., phase structure, electronic and ionic conductivity to understand the reaction kinetics at different scales. This work provides new insights in understanding the electrochemical properties of Ni-rich cathode at different levels to inspire revolutionary ideas to address the fundamental issues of Ni-rich cathode from materials to relevant electrode levels.

Hu, Jiangtao↗

New Synthesis Strategies to Improve Co-Free LiNi0.5Mn0.5O2 Cathodes: Early Transition Metal d0 Dopants and Manganese Pyrophosphate Coating

In this work, we report solution-based doping and coating strategies to improve the electrochemical performance of the Co-free layered oxide cathode LiNi0.5Mn0.5O2 (LNMO). Small amounts of d0 dopants (e.g., Mo6+and Ti4+, 0.5-1 at. %) increase the cathode’s specific capacity, cycling stability, and rate capability. More specifically, a Mo-doped cathode with the nominal composition LiNi0.495Mn0.495Mo0.01O2 achieves a high reversible capacity of 180 mAh/g at 20 mA/g with good retention at higher rates (e.g., 120 mAh/g at 100 mA/g). Effects of 1 at.% Mo dopant on the cathode structure were studied using a suite of characterization tools including X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). These measurements demonstrate that Mo6+ reduces Li+/Ni2+cation mixing and mitigates undesirable phase transformations near the cathode surface during cycling. This work also reports the use of an inorganic Mn2P2O7 coating which enhances cycling stability, presumably through formation of a stable cathode electrolyte interphase (CEI) layer. Overall, the synthesis approaches reported herein are quite general and can potentially be expanded to other high voltage LIB cathodes.

Co-free cathodes, d0 cation, pyrophosphate coating↗

Probing the electrolyte/electrode interface with vibrational sum frequency generation spectroscopy: A review

Over the past decades, Lithium-ion batteries have seen extensive improvements, and as a result are now the primary choice in many applications for their power, energy, and durability. In recent years, battery cost has reduced by orders of magnitude through adoption of new materials and processes. Despite these advances, interfaces in these battery systems are yet to be fully understood. This is seen as a major limitation to further increase cycle life, calendar life, abuse tolerance, and performances. A major obstacle is a lack of comprehensive understanding of the complex dynamic chemical processes occurring at the electrolyte/electrode interface. In this context, vibrational sum frequency generation (vSFG) spectroscopy possesses the unique capability of probing a molecularly thin interfacial layer to obtain molecular-level information through nonlinear optical interaction. Probing the molecular level processes at the interfaces using such a versatile technique would be a game changer in the advancement of current battery research knowledge. This review article summarizes recent vSFG studies on the electrolyte/electrode interface of various electrode materials and nonaqueous electrolytes for LIBs and discusses future research perspectives. Finally, overall, this focused review highlights the advantages and versatility of vSFG that can be used to further advance present-day battery research.

25 ENERGY STORAGE↗

Lithium substituted poly(amic acid) as a water-soluble anode binder for high-temperature pre-lithiation

Multifunctional binders hold great promise in advanced electrode designs for both fundamental research and practical utilization of lithium-ion batteries (LIBs). The reactions between Si/SiO x -dominated anodes with lithium are expected to be exothermic in principle, while the thermal tolerance along with the volume change makes high-temperature binders attractive for large scale roll-to-roll manufacturing. For instance, if a high temperature binder is also water soluble, it can be compatible with the current graphite-based anode manufacturing process. In this work, we present a water-soluble poly(amic acid)-based binder, which can withstand high temperature for industrial pre-lithiation process and effectively hold active materials together during repeated charge and discharge cycles. This lithium substituted poly(amic acid) binder (denoted as Li-Pa) can serve as a drop-in replacement for environmentally friendly electrode fabrication in large scale by providing aqueous solubility, exceptional thermal stability and mechanical flexibility.

25 ENERGY STORAGE↗

(CrMnCoNiZn) 3 O 4 @PPy core-shell nanocomposite with excellent electrochemical performance as lithium-ion battery anode

High entropy oxides (HEOs) have an excellent potential for use as electrode materials in lithium-ion batteries (LIBs) due to their high theoretical specific capacity. In this work, spinel-structured (CrMnCoNiZn) 3 O 4 HEO nanoparticles with five elements in equal molar ratio is first generated by solution combustion method. (CrMnCoNiZn) 3 O 4 @polypyrrole (PPy) nanocomposites are prepared by in-situ polymerization method. As an anode for lithium-ion batteries, the electrochemical performance of the (CrMnCoNiZn) 3 O 4 @PPy composite outperforms that of (CrMnCoNiZn) 3 O 4 nanoparticles. The capacity is 802 mAh/g after 100 cycles at a current density of 100 mA/g, 416 mAh/g after 1000 cycles at a high current density of 1 A/g, and 360 mAh/g rate capacity at 2 A/g. The excellent electrochemical performance of the composites is mainly due to the fact that the conductive and flexible PPy is encapsulated on the high-entropy oxides, which can alleviate the volume change triggered by extraction-insertion of lithium ions process, as well as enhance the electrical conductivity and reduce the occurrence of some side reactions. Finally, this method of compositing materials can also be used in other HEOs and conductive polymers, providing a new idea to enhance the electrochemical properties of HEOs.

25 ENERGY STORAGE↗

High-entropy Li-rich layered oxide cathode for Li-ion batteries

High-entropy oxides (HEOs) are emerging as promising cathode materials for Li-ion batteries (LIBs) due to their stable solid-state phase and compositional flexibility. Herein, we investigate the structural and electrochemical properties of a novel non-equimolar high-entropy cathode material, termed high-entropy Li-rich layered oxide (HE-LLO, Li 1.15 Na 0.05 Ni 0.19 Mn 0.56 Fe 0.02 Mg 0.02 Al 0.02 O 1.97 F 0.03 ), in comparison to a pristine Li-rich layered oxide (PR-LLO, Li1.2Ni0.2Mn0.6O2). The incorporation of multiple cations (Na + , Al 3+ , Mg 2+ , Fe 3+ ) and anion (F - ) into HE-LLO introduces compositional diversity, enhancing structural stability through the entropy stabilization effect. Theoretical calculations confirm a significantly higher configurational entropy in HE-LLO compared to PRLLO, supporting its high-entropy nature. Electrochemical evaluations demonstrate that HE-LLO exhibits considerable capacity retention, preserving 76.8 % of its discharge capacity at 0.5C after 200 cycles, compared to only 36.2 % for PR-LLO. Even under high-temperature conditions, HE-LLO outperformed PR-LLO, maintaining 76.1 % of its discharge capacity after 100 cycles at 5C, while PR-LLO retained only 12.4 %. These enhancements are attributed to the improved phase reversibility and higher Li + ion diffusion coefficients of HE-LLO, validated by ex-situ characterizations using a synchrotron X-ray technique, along with density functional theory (DFT) calculations. In conclusion, these findings highlight the promise of non-equimolar HEOs as a novel design strategy for highperformance cathode materials.

25 ENERGY STORAGE↗

Long carbon fibers boost performance of dry processed Li-ion battery electrodes

Dry processing (DP) is an advanced manufacturing technique for lithium-ion battery (LIB) electrodes. Unlike conventional wet-process-based manufacturing that involves dissolving polyvinylidene fluoride (PVDF) binder in n-methyl-2-pyrrolidone (NMP) solvent for slurry-casting, DP involves fibrillation of polymer binders. This method offers environmental and cost benefits by eliminating the need for expensive and environmentally hazardous organic solvents. However, DP-produced electrode films often lack mechanical stability due to the absence of a current collector substrate during electrode material layer fabrication. This reduced mechanical instability results in difficulty during fabricating of thin electrodes (≈5 mAh/cm 2 ). To address this issue, long (>8 mm) carbon fiber (CF) has been incorporated to reinforce the mechanical strength of the electrode films. In conclusion, the study demonstrates that the inclusion of long carbon fiber boosts the mechanical, electrical, thermal, and electrochemical performance of DP electrodes.

25 ENERGY STORAGE↗

Surface modification of cathode material enhances electrochemical performance in dry-processed Li-ion battery electrodes

The transition to electric vehicles (EVs) is pivotal for achieving energy security and integrating grid stability, with lithium-ion batteries (LIBs) playing a central role in this transformation. However, the conventional wet electrode manufacturing relying on N-methyl-2-pyrrolidone (NMP) solvent is energy intensive and costly. Dry processing (DP) has emerged as a promising alternative, eliminating solvents and using polytetrafluoroethylene (PTFE) binder for electrode fabrications. Despite its advantages, DP faces a critical challenge: poor interfacial adhesion between the hydrophobic PTFE binder and the hydrophilic cathode active material (CAM), particularly LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811), which undermines electrode performance. Here, to address this, we introduced a novel vapor-phase trimethoxymethylsilane (TMMS) coating to hydrophobize the CAM surface, enhancing compatibility with PTFE. This surface modification significantly enhances binder – CAM interactions, enabling uniform mixing and robust electrode integrity without damaging the CAM particles. Our findings advance the feasibility of environmentally sustainable and cost-effective dry processing, representing a significant step toward sustainable battery manufacturing.

Choi, Junbin [Oak Ridge National Laboratory (ORNL)↗

Interface-engineered (AlMnCoNiZn) 3 O 4 @PPy nanocomposites for superior lithium storage: Mechanism and performance

The practical application of graphite anodes in lithium-ion batteries (LIBs) is constrained by low specific capacity (372 mAh g -1 ) and sluggish kinetics. Here, to address these limitations, our present study focuses on high-entropy oxides (HEOs), which offer high theoretical capacity and structural stability. We synthesized spinel-structured (AlMnCoNiZn) 3 O 4 nanoparticles via a solution combustion method and fabricated an (AlMnCoNiZn) 3 O 4 @polypyrrole (PPy) nanocomposite through in-situ polymerization. Our electrochemical tests demonstrate that the PPy modification significantly enhances performance. While the pristine (AlMnCoNiZn) 3 O 4 delivered 445 mAh g −1 after 100 cycles at 100 mA g −1 and 350 mAh g −1 after 1000 cycles at 1000 mA g −1 , the (AlMnCoNiZn) 3 O 4 @PPy composite achieved 695 mAh g −1 after 100 cycles and maintained 675 mAh g −1 after 1000 cycles. Furthermore, the composite improved rate capacity at 1000 mA g −1 from 211 mAh g −1 to 403 mAh g −1 . This work highlights how conductive and flexible polymer modifications can dramatically improve the electrochemical properties of HEOs. The developed (AlMnCoNiZn) 3 O 4 @PPy composite provides a promising direction for designing advanced anodes to meet next-generation energy storage demands.

Anodes material↗

Understanding of three different polyvinylpyrrolidone (PVP) based battery binders blends on graphene surfaces from first principles via DFT simulations

Binders play a crucial role in binding electrodes, current collectors, and conductive agents during battery manufacturing. The selection of the binders and their blends considerably affect various properties such as mechanical durability, adhesion performance, ionic/electronic conductivities, and solid electrolyte interface stability for lithium-ion batteries. In this work, polyvinylidene di-fluoride (PVDF), polyacrylic acid (PAA), polyvinylpyrrolidone (PVP), and lithiated polyacrylic acid (Li-PAA) were selected as the model binders, and their blends were studied on graphene surfaces. Further, among them, PVDF is hardly soluble in water unlike the other binders, so in practice, the blend of PVP:PVDF is not thought to be a proper combination. However, the PVP:PVDF binder has also been included because the purpose of this work is to calculate several electronic properties such as binding energies, intermolecular interaction energies, bond critical points, electron density, and the Laplacian of electron density at critical bonding regions of all these blends at the molecular level via density functional theory (DFT) simulations in order to evaluate and compare how is the interaction strength and bonding type of three different lithium-ion batteries (LIBs) binder blends on graphene surfaces. Most stable binder pairs and their binding mechanisms on graphene surfaces were studied. The delocalization of lithium in Li-PAA was studied with the presence of water.

25 ENERGY STORAGE↗

Size effect on the growth and pulverization behavior of Si nanodomains in SiO anode

Silicon monoxide (SiO) as a promising silicon-based anode electrode of lithium-ion batteries (LIBs) has been the subject of many recent investigations. However, the complex microstructural features of SiO hinder attempts to link the microstructure changes in SiO with its electrochemical performances upon electrochemical cycling. This study employs X-ray pair distribution function (PDF), with a high-resolution transmission electron microscope (HRTEM), to investigate the microstructure of Si nanodomains in SiO and its structural evolution over the electrochemical cycling process. The experiment results reveal the size evolution of Si nanodomains in SiO during the electrochemical cycling and find it highly dependent on the initial Si domain size in SiO. If the initial Si domain size is too large, the average size of Si nanodomains would increase at first and then decrease after a certain number of cycles, which indicates the pulverization of Si domains after the electrochemical-driven growth of Si nanodomains reaches a critical point. Furthermore, these results suggest that an optimal initial Si nanodomain size of 4-6 nm for SiO anode materials is essential to retard the growth and subsequent pulverization process of Si nanodomains and thus to improve the cyclability of SiO during long-term cycling.

25 ENERGY STORAGE↗

Understanding fundamental effects of Cu impurity in different forms for recovered LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode materials

When identifying and developing lithium ion battery recycling technologies, understanding the role of impurities is always a concern as they may have an impact on electrochemical performance, material stability, or lifetime for recovered active materials. In this work we show that Cu impurity in different forms could play very different roles on the recovered LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622). Cu metal impurity could easily short the cell, while Cu ion impurity could play a positive role due to partially substitution of the Ni 2+ sites to lower the cation mixing degree. In specific, NCM622 material with certain amount (0.34 at%) of Cu ion impurity delivers high initial specific charge/discharge capacity of 211.8 and 186.0 mAh g -1 at 0.05 C, which are 12.2 and 14.1 mAh g -1 higher than those of virgin NCM622 cathode. Moreover, a superior retention capacity of 171.3 mAh g -1 after 90 cycles at 0.33 C, and striking rate capability are achieved in this NCM622 cathode sample. These results clearly indicate that Cu metal impurity should be avoided and the ionic Cu impurity should be controlled with optimal concentration during recycling process for spent LIBs.

25 ENERGY STORAGE↗

Targeted masking enables stable cycling of LiNi 0.6 Co 0.2 Mn 0.2 O 2 at 4.6V

Layered LiNi x Co y Mn 1–x-y O 2 (NCM, or NCMxy(1-x-y)) is a dominant family of cathode materials for lithium-ion batteries (LIBs) due to its high energy density. Among all NCM cathode materials, NCM622 possess the optimal energy density at high potential (≥ 4.6 V vs. Li/Li + ). However, the practical application of NCM622 at high voltage (≥ 4.6 V) is limited by its parasitic reactions and associated safety concerns. Completely physical isolation has been considered as the main approach to mitigate the parasitic reaction. It has also been previously demonstrated that the interface reaction has active site selectivity, and that the reactivity of the active sites can effectively suppressed by blocking the chemically active sites. Herein, a targeted masking by LiFePO 4 @C nanoplates is reported to unlock the stable performance of NCM622 up to 4.6 V vs. Li/Li + . The (targeted masked-NCM622)|graphite pouch cell shows 86.5% capacity retention after 1000 cycles and its maximum temperature during thermal runaway is dramatically reduced from 570 °C to 415 °C. Systematic in/ex situ characterizations, first-principles calculations and half/pouch targeted LiFePO 4 @C covers the surface of NCM partcell evaluation prove that PO 4 3- is preferentially adsorbed on transition metal sites, stabilizing both the transition metal ions and oxygen ions on the surface against the ethylene carbonate-containing traditional electrolyte even under high voltage (≥ 4.6 V vs. Li/Li + ). Furthermore, this work opens up new venue for rational design of high-performance cathode materials through a low-cost and scalable decoration process, and reveal a new understanding of interfacial activity of materials.

25 ENERGY STORAGE↗

Ultrahigh rate capability of manganese based olivine cathodes enabled by interfacial electron transport enhancement

In this study, manganese-based Olivine is a promising cathode candidate with high energy and low cost for Li-ion batteries (LIBs). Its rate capability and cyclability challenges still remain even with nano-size and carbon coating. Herein, an ultrahigh rate performance is achieved by introducing an affinitive conductor to enhance the interfacial electron transport of LiMn 0.7 Fe 0.3 PO 4 via Li 3 V 2 (PO 4 ) 3 . It is found that the Li 3 V 2 (PO 4 ) 3 facilitates sp 2 hybridization to form a highly conductive carbon coating during the carbonized process. The composite 0.9LiMn 0.7 -Fe 0.3 PO 4 .0.1Li 3 V 2 (PO 4 ) 3 can deliver a capacity of 90.9 mAh g -1 and power density of 11444 W kg -1 at 50 C-rate. Both in situ X-ray diffraction and conductive-atomic force microscopy are conducted to understand the synergetic effect between LiMn 0.7 Fe 0.3 PO 4 and Li 3 V 2 (PO 4 ) 3 . The results suggest that the interfacial electron transfer between LiMn 0.2 Fe 0.3 PO 4 particles and the electron conducting medium, such as binder/carbon black composite, is greatly improved so that the highly Li + conductive nature of olivine materials can be fully unleashed. This work demonstrates the importance of efficient interfacial electron transfer to the active cathode particles, and opens up a new venue for the rational design of high-energy and high-power batteries.

25 ENERGY STORAGE↗

Demonstration of an All-Refractory Corrosion-Resistant Molten Salt Pumping and Storage Infrastructure Up to 950 degrees C

Concentrating solar power (CSP) with thermal energy storage (TES) has an estimated cost similar to solar photovoltaics (PV) with lithium-ion batteries (LIB), but CSP + TES has the potential for significantly reduced cost by operating above 700 degrees C. However, this requires a TES medium and containment infrastructure which are chemically compatible and do not degrade above 700 degrees C. MgCl2-KCl-NaCl (MKN) salt is a promising medium, but when MKN salt has small amounts of water and oxygen dissolved in it, it excessively corrodes conventional commercial alloys. Here, we consider refractory materials including graphite, carbon-carbon composite (C/C), and molybdenum because they maintain high mechanical strength at elevated temperatures and are expected to resist corrosion by MKN salt. While selection of refractory materials is often constrained by the need to remain chemically stable in air, this work uses an enclosure filled with inert gas to allow the use of materials like graphite and molybdenum. Notably, graphite components can seal against liquids unlike many brittle refractory materials. We demonstrate a centrifugal pump and mechanical seals made of refractory materials in a laboratory-scale circulation loop, which successfully operated continuously for more than 49 h at temperatures ranging from 750 degrees C to 950 degrees C with no mechanical failures or chemical degradation of the refractory materials. To the best of our knowledge, this is the highest temperature molten salt circulation loop that has been successfully developed, and this refractory infrastructure allows for operation at even much higher temperatures (<1600 degrees C) if a storage medium with a lower vapor pressure is used. The principles of this architecture are relevant to other applications with high temperature flowing metals and salts including Generation IV nuclear fission reactors for power production and molten salt electrolysis reactors for metallurgical processing.

14 SOLAR ENERGY↗

Interphasial engineering for Ni-rich NMC cathode materials

Ni-rich LiNi 1-x-y Mn x CoyO 2 , (NMC: 1-x-y ≥ 0.6) are promising cathode materials for lithium-ion batteries (LIBs) due to high reversible capacity and low cost. However, the fast capacity decay and voltage fading caused by interphasial instability requires improvement. The unstable cathodeelectrolyte interphase (CEI) and transition metal (TM) dissolution at higher voltages can lead to the drastic deterioration of electrochemical performance. In this review, recent approaches to novel electrolyte and additive design, cathode engineering including artificial CEI, and doping/coating on the surface of particles or the whole electrode are comprehensively summarized. In conclusion, the importance of multi-model and multi-scale characterization methods in understanding the effects of interphasial chemistry on battery performance is highlighted.

25 ENERGY STORAGE↗