SATI: Scalable And Traffic efficient data dissemination Infrastructure for sensor-based distributed information services

When highly distributed data streaming services are fully realized, they will bring up new issues in delivering data streams to data consumers. First, data delivery scheme should be traffic efficient because the Internet can be easily inundated by a massive number of data streams. Also, the probing messages generated by many delivery schemes waste network resources. These problems are not easily solved by existing data delivery schemes because none of them consider the economic usage and measurement of network resource. This paper proposes SATI, an infrastructure that provides not only shared management and measurement of network information but also scalable and traffic efficient data delivery. Experimental results show that SATI is scalable and greatly reduces network traffic. I

Gas Evolution Kinetics in Overlithiated Positive Electrodes and its Impact on Electrode Design

Abstract Increasing lithium contents within the lattice of positive electrode materials is projected in pursuit of high‐energy‐density batteries. However, it intensifies the release of lattice oxygen and subsequent gas evolution during operations. This poses significant challenges for managing internal pressure of batteries, particularly in terms of the management of gas evolution in composite electrodes—an area that remains largely unexplored. Conventional assumptions postulate that the total gas evolution is estimated by multiplying the total particle count by the quantities of gas products from an individual particle. Contrarily, this investigation on overlithiated materials—a system known to release the lattice oxygen—demonstrates that loading densities and inter‐particle spacing in electrodes significantly govern gas evolution rates, leading to distinct extents of gas formation despite of an equivalent quantity of released lattice oxygen. Remarkably, this study discoveres that O2 and CO2 evolution rates are proportional to 1O2 concentration by the factor of second and first‐order, respectively. This indicates an exceptionally greater change in the evolution rate of O2 compared to CO2 depending on local 1O2 concentration. These insights pave new routes for more sophisticated approaches to manage gas evolution within high‐energy‐density batteries

Suppressing High-Current-Induced Phase Separation in Ni-Rich Layered Oxides by Electrochemically Manipulating Dynamic Lithium Distribution

Understanding the cycling rate-dependent kinetics is crucial for managing the performance of batteries in high-power applications. Although high cycling rates may induce reaction heterogeneity and affect battery lifetime and capacity utilization, such phase transformation dynamics are poorly understood and uncontrollable. In this study, synchrotron-based operando X-ray diffraction is performed to monitor the high-current-induced phase transformation kinetics of LiNi0.6Co0.2Mn0.2O2. The sluggish Li diffusion at high Li content induces different phase transformations during charging and discharging, with strong phase separation and homogeneous phase transformation during charging and discharging, respectively. Moreover, by exploiting the dependence of Li diffusivity on the Li content and electrochemically tuning the initial Li content and distribution, phase separation pathway can be redirected to solid solution kinetics at a high charging rate of 7 C. Finite element analysis further elucidates the effect of the Li-content-dependent diffusion kinetics on the phase transformation pathway. The findings suggest a new direction for optimizing fast-cycling protocols based on the intrinsic properties of the materials

A Kinetic Indicator of Ultrafast Nickel-Rich Layered Oxide Cathodes

Elucidating high-rate cycling-induced nonequilibriumelectrodereactions is crucial for developing extreme fast charging (XFC) batteries.Herein, we unveiled the distinct rate capabilities of a series ofNi-rich layered oxide (NRLO) cathodes by quantitatively establishingtheir dynamic structure-kinetics relationships. Contrary toconventional views, we discovered electrode kinetic properties obtained ex-situ near equilibrium states failed to assess the effectiverate capability of NRLOs at ultrafast C rates. Further, the kineticphase heterogeneity, characterized by the dynamic separations in in-situ X-ray diffraction patterns and deviations in NRLO c-axis lattice parameters, exclusively correlated with thecapacity reduction under XFC and became an effective indicator ofthe NRLO rate capability. Enhancing the cycling temperature boostedthe rate capability of studied NRLOs by similar to 10%, which was furtherverified to mitigate the kinetic phase heterogeneity during XFC. Overall,this study lays the groundwork for tuning the kinetic phase heterogeneityof electrodes to develop ultrafast batteries.N

A Kinetic Indicator of Ultrafast Nickel-Rich Layered Oxide Cathodes

Elucidating high-rate cycling-induced nonequilibrium electrode reactions is crucial for developing extreme fast charging (XFC) batteries. Herein, we unveiled the distinct rate capabilities of a series of Ni-rich layered oxide (NRLO) cathodes by quantitatively establishing their dynamic structure–kinetics relationships. Contrary to conventional views, we discovered electrode kinetic properties obtained ex-situ near equilibrium states failed to assess the effective rate capability of NRLOs at ultrafast C rates. Further, the kinetic phase heterogeneity, characterized by the dynamic separations in in-situ X-ray diffraction patterns and deviations in NRLO c-axis lattice parameters, exclusively correlated with the capacity reduction under XFC and became an effective indicator of the NRLO rate capability. Enhancing the cycling temperature boosted the rate capability of studied NRLOs by ∼10%, which was further verified to mitigate the kinetic phase heterogeneity during XFC. Overall, this study lays the groundwork for tuning the kinetic phase heterogeneity of electrodes to develop ultrafast batteries