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As data center networks grow in scale and complexity, the active inband network telemetry (AINT) system collects a broader range of network status metrics to provide comprehensive visibility for AINT-related network applications, but it also leads to higher measurement costs. To address this issue, we introduce the Flexible Attention-shifting Network Telemetry (FANT), which dynamically focuses on critical links in each measurement cycle. Specifically, FANT employs a metric categorization strategy that divides all measurement metrics into two categories: basic measurements, which are lightweight but cover fewer metrics, and detailed measurements, which are comprehensive but incur higher overhead. Based on the analysis of the previous cycle's measurements, FANT identifies which links are suspicious and then activates certain probe traces through an attention-shifting mechanism to collect detailed measurements of these links in the current cycle. To further save bandwidth, we model the attention-shifting process and apply heuristic algorithms to solve it. Our experiments show that FANT effectively supports the operation of ANT network applications. In a fat-tree topology with 30 pods, FANT significantly reduces bandwidth usage to 42.6% of the state-of-the-art solution. For scenarios requiring rapid computation, FANT can accelerate algorithm execution 10 5 × by setting acceleration factors, with only a 6.4% performance loss. [ABSTRACT FROM AUTHOR]

Accurate quantification of the aging mechanisms of batteries at accelerated aging conditions is of great significance for lithium‐ion batteries (LIBs). Here the aging and rollover failure mechanisms of LiFePO4 (LFP)/graphite batteries at different temperatures are investigated using a combination of advanced techniques such as electrolyte quantification methods, mass spectrometry titration (MST), time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), and Raman imaging. The growth, rapture, and repair process of the solid electrolyte interphase (SEI) is the primary mechanism leading to battery aging, and its contribution increases with temperature. High temperature exacerbates electrolyte decomposition (especially lithium salts), together with organic SEI decomposing into the more stable inorganic SEI at high temperature, resulting in a thicker SEI rich with inorganic compositions. High temperatures also lead to spatially inhomogeneous side reactions, which may in turn accelerate further degradation of the battery. The sharp battery capacity decline, namely the rollover failure, is primarily due to the depletion of additive VC, which shifts electrolyte degradation from additive VC to solvents and lithium salts, rather than by the increase of internal resistance, lithium plating, electrolyte drying out, electrode saturation, or mechanical deformation. [ABSTRACT FROM AUTHOR]

The aging of lithium‐ion batteries (LIBs) typically accompanies the degradation of electrolyte, but the relationship between them remains unclear. Therefore, quantifying residual electrolyte in batteries at different states of health (SOH) is a crucial issue. Here, we have developed a comprehensive characterization method to quantitatively analyze the electrolyte salts, solvents, and additives in commercial pouch cell, achieving quantification of all electrolyte compositions with high accuracy. Compared to the reported external standard method used in gas chromatography‐mass spectrometry (GC‐MS), we developed an internal standard method, which offers higher accuracy and reliability, with the maximum error decreased from 9.54 % to 3.48 %. Moreover, the quantitative accuracy of the calibration curves remains unchanged after 2 months. Multi‐instruments analysis is also utilized for the extraction and quantitative analysis of electrolyte in practical battery systems, achieving less than 5 % quantification error for all compositions. With our proposed method, it becomes possible to determine the absolute amounts of all electrolyte compositions, rather than obtaining limited information such as concentration or relative content. It is believed that this protocol of quantifying electrolyte compositions in commercial cells could serve as a baseline for further studies to reveal the relationship between electrolyte degradation and battery aging. [ABSTRACT FROM AUTHOR]

Quantifying the aging mechanisms and their evolution patterns during battery aging is crucial for enabling renewable energy. Here, key factors are monitored and quantified affecting the aging processes of LiFePO4//graphite battery by a combination of mass spectrometry titration (MST), nuclear magnetic resonance (NMR), cryogenic transmission electron microscopy (cryo‐TEM), and neutron imaging techniques. Electrochemical analysis reveals the loss of active lithium inventory drives battery aging as temperature increases. It is shown that temperature‐induced accelerated decaying rate is 2.01 and 3.45 times at 45 and 65 °C compared with that of rate at 25 °C. Quantitative analysis indicates that irreversible formation of LixC6 (x ≤ 1), LiF, ROCO2Li, LiH, Li2C2, and RLi (R = CH3, C2H3, C2H5, C3H5) are the primary components of inactive lithium. The solid eletrolyte interpahse (SEI), excluding LixC6, constitutes over 70% of the total inactive lithium. With increasing cycles, SEI shows a decreasing proportion of LiF and an increasing proportion of ROCO2Li. The coupled effects of substantial SEI growth, increased irreversible formation of LixC6, and worsened conductivity result in the rapid aging of batteries tested at high temperatures. In this work, a research toolbox for the quantitative study of aging mechanisms in practical batterysystems has been provided. [ABSTRACT FROM AUTHOR]

Li plating is widely known as the key factor leading to degradation and safety issues in lithium‐ion batteries (LIBs). Herein, the feasibility of monitoring the onset and progression of Li plating is proposed and justified in the graphite/LiFePO4 pouch cell by an operando impedance‐thickness combinational technique. First, as a proof‐of‐concept, the real‐time thickness/impedance variations of LIBs during charging at low temperature (≈0 °C) are obtained and dissected. Three distinct stages corresponding to different Li plating patterns are observed with the critical changing points of charge‐transfer resistance, which match well with the counterpoints in the differential thickness/capacity curves. Post‐mortem analysis by Mass Titration and Scanning Microscopy also indicate that these stages are Li intercalation, Li nucleation & nuclei growth, and Li dendrite growth, respectively. Thereafter, different cycling protocols are proposed and carried out to test the as‐mentioned Li plating processes by this novel technique. The results disclose that the extensive deposition of metallic Li significantly intensifies the loss of Li inventory, leading to cell aging or even a "capacity plunge", and depict a safer boundary plot about preventing the occurrence of "Li plating" region. This work provides new insights on Li plating behavior and battery safety control under harsh operational conditions. [ABSTRACT FROM AUTHOR]

Given that the non‐aqueous electrolyte in Li‐ion battery plays a specific role as an ion‐transport medium and interfacial modifier for both cathode and anode, understanding and evaluating the evolution and degradation of electrolytes throughout the life cycle is a fundamental concern within the lithium‐ion battery (LIB) community. This article provides a comprehensive overview of the electrolyte decomposition processes, mechanisms, effects of electrolyte degradation on the battery performance, characterization techniques, and modeling analysis. First, it thoroughly discusses the processes and mechanisms involved in electrolyte degradation from two primary perspectives: 1) the formation of the electrode‐electrolyte interphase and 2) the decomposition of the bulk electrolyte. Subsequently, it systematically outlines the effects of electrolyte degradation on the battery performance. The article further introduces cutting‐edge characterization and detection techniques used to assess electrolyte degradation, with a specific emphasis on quantitative methods for analyzing residual electrolytes in practical cells. Moreover, it summarizes advanced physical models of electrolyte decomposition. Finally, the paper concludes by offering insights into future trends and potential challenges in battery degradation research, it offers valuable references and guidance for further exploration of electrolyte degradation in LIBs. [ABSTRACT FROM AUTHOR]

Highlights: Oxygen functional groups improve rate capability as well as long-term cycling stability of graphite oxide. The adsorption-intercalation hybrid K+ storage mechanism of graphite oxide (GO) is elucidated by in situ Raman spectroscopy and systematic electrochemical characterization. It is unraveled that the C = O and COOH rather than C-O-C and OH groups contribute to the formation of highly conductive, intact and robust solid electrolyte interphase.Oxygen-containing functional groups were found to effectively boost the K+ storage performance of carbonaceous materials, however, the mechanism behind the performance enhancement remains unclear. Herein, we report higher rate capability and better long-term cycle performance employing oxygen-doped graphite oxide (GO) as the anode material for potassium ion batteries (PIBs), compared to the raw graphite. The in situ Raman spectroscopy elucidates the adsorption-intercalation hybrid K+ storage mechanism, assigning the capacity enhancement to be mainly correlated with reversible K+ adsorption/desorption at the newly introduced oxygen sites. It is unraveled that the C=O and COOH rather than C-O-C and OH groups contribute to the capacity enhancement. Based on in situ Fourier transform infrared (FT-IR) spectra and in situ electrochemical impedance spectroscopy (EIS), it is found that the oxygen-containing functional groups regulate the components of solid electrolyte interphase (SEI), leading to the formation of highly conductive, intact and robust SEI. Through the systematic investigations, we hereby uncover the K+ storage mechanism of GO-based PIB, and establish a clear relationship between the types/contents of oxygen functional groups and the regulated composition of SEI. [ABSTRACT FROM AUTHOR]

The dissolution of iron from the cathode significantly contributes to the accelerated degradation of LiFePO4/Graphite batteries, particularly at elevated temperatures. However, a systematic understanding of the spatial distribution and impact of Fe ions on the dynamic solid electrolyte interphase (SEI) layer is lacking. In this study, a comprehensive and quantitative investigation is conducted into the effects of transition metals (TM) and thoroughly examined the interaction between dissolved Fe2+ and SEI in long‐life LiFePO4/Graphite pouch cells. The dissolved Fe in the electrolyte is more prone to deposition at the negative electrode at elevated temperatures, leading to an accelerated loss of active lithium. Additionally, Fe deposition on the SEI catalyzes the decomposition of EC and contributes to an increase in organic components, particularly lithium alkyl carbonates within the SEI, as evidenced by mass spectrometry titration (MST) analysis. Neutron imaging (NI) provides more insights into the impacts of dissolved Fe2+ on active lithium loss, SEI components, and electrolyte decomposition, resulting in greater macroscopic heterogeneity in the electrode regions of the cells. This research sheds light on the mechanisms underlying the degradation of LiFePO4/Graphite batteries and provides valuable insights for the development of strategies to mitigate capacity fade and enhance battery performance and longevity. [ABSTRACT FROM AUTHOR]

Quantitative analysis of the aging process of lithium-ion batteries by using electrochemical thermodynamic and kinetic parameters such as electrochemical potential, Li stoichiometry, and Li inventory loss is a key research topic in the development of Li-ion battery for electric vehicles and smart grids. It is generally known the above parameters can be acquired through the analysis of Electromotive Force (EMF) or Open-Circuit Voltage (OCV) curves. In this work, we proposed and applied five EMF measurement techniques to obtain the EMF-SoC relationships in LFP/Gr single-layer laminated pouch cells at different temperatures and States of Health (SoH), and comprehensively examined them from the viewpoints of eight evaluation dimensions. A Python program, named Degradation Modes Analysis (DMA), is used to diagnose the thermodynamic degradation modes of the battery automatically. Furthermore, electrochemical kinetic parameters were also extracted along with the depolarization process. For faster and more accurate aging diagnosis, we recommend an optimal blend of short relaxation time GITT (Short-Rest-GITT) and extrapolated EMF (Extrap-EMF) to reach the most precise EMF measurements and gain the most comprehensive information about battery thermodynamics and kinetics at the same time. [Display omitted] • Five EMF measurement techniques for Li-ion batteries are compared. • LFP/Gr batteries aged at three temperatures are analyzed. • A written DMA Python program is presented. • Kinetic parameters are extracted during the depolarization process. [ABSTRACT FROM AUTHOR]

Designing low-cost preparation of high-activity electrocatalysts with excellent stability is the route one must take to fully realize large-scale application implementation of zinc-air batteries. 3D nitrogen-doped nanocarbons with transition metals or their derivatives encapsulated in show promising potential in the field of non-precious metal oxygen electrocatalysis. Herein, we report a simple, economical, and large-scale production method to construct worm-like porous nitrogen-doped carbon with in situ -grown carbon nanotubes and uniformly embedded Fe/Fe 3 C nanoparticles. It not only has high conductivity owing to the nitrogen-doped nature but also has ample active sites and electrolyte diffusion channels benefitting from the uniformly distributed heterostructural Fe/Fe 3 C nanoparticles and discrete hierarchically porous structures. When used as catalyst materials for a zinc-air battery, an energy density of 719.1 Wh kg -1 and a peak power density of 101.3 mW cm -2 at a 50 mA cm -2 discharge current density is achieved. Additionally, throughout charging and discharging for 200 cycles at a current density of 20 mA cm -2 , the charge/discharge voltage gap is nearly constant.