Battery Configuration Research Articles

Long-cycle-life Li2MnO3 thin-film cathode enabled by all-solid-state battery configuration

Li2MnO3 (LMO) is a key component in lithium-rich manganese-based oxides (LMROs) and has attracted great attention as a cathode for lithium-ion batteries (LIBs) due to its high theoretical capacity and cost-effectiveness. However, its severe capacity fading and discharge voltage decay during prolonged cycling greatly hinders its applications. In this study, an LMO film is prepared, followed by the fabrication and investigation of an LMO/LiPON/Li all-solid-state thin film lithium battery (LMO-TFLB). The results show that although the LiPON electrolyte deposition results in the formation of a disordered interface layer derived from the LMO layer, an LMO/LiPON interface with small interfacial resistance and good structural stability during cycling is obtained, allowing fast Li+ diffusion across the interface. Furthermore, in contrast to the half cell that uses liquid electrolyte (LMO-LIB), the LiPON electrolyte in the LMO-TFLB significantly aids in impeding the Mn dissolution to prevent active material loss. More importantly, although a structural transformation from a layered LMO phase to a spinel-like phase occurs in the cathode of the LMO-TFLB during cycling, the transformed spinel-like phase with a higher crystallinity than that in the LMO-LIB facilitates fast Li+ and electron transport to improve the LMO-TFLB's capacity. Consequently, the LMO-TFLB exhibits a long cycle life without any capacity loss after 1000 cycles, which outperforms that of the LMO-LIB (20% capacity retention after 450 cycles). This work demonstrates that all-solid-state battery configuration is highly promising for unlocking the full potential of LMROs cathode materials for LIBs.

Modeling the propagation of internal thermal runaway in lithium-ion battery

The trend toward high capacity and huge size in lithium-ion batteries has made it necessary to investigate the internal thermal characteristics. In this study, a thermal runaway model was developed to describe lithium-ion batteries' internal thermal characteristics. Moreover, triggering energy was proposed as a critical feature for evaluating and characterizing the thermal runaway under diverse thermal abuse situations, with large differences among characteristic temperatures. Finally, the effects of battery configuration on thermal runaway behaviors were investigated. The modeling results showed that internal temperature distribution can be divided into four characteristic stages with two jelly rolls, and the application of more numerous and thinner cells inside a battery can accelerate the propagation of thermal runaway. The experimental results showed that the ratio of triggering energy of self-heat onset to total self-heat generation remained consistent in an adiabatic environment. The mean value of the ratio was 24.5%, indicating that lithium iron phosphate batteries obtain most of the energy (generally 80%) from internal exothermic reactions during adiabatic thermal abuse. The triggering energy of thermal runaway remained constant when various heating powers were applied to one of the batteries' laterals (about 20.8% of theoretical energy contained inside lithium iron phosphate batteries). Triggering energy can provide new insights into the modeling of thermal runaway mechanisms and propagation.

A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries

Solid polymer electrolytes (SPEs) have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility, scalability, and interface compatibility with electrodes. Herein, a novel all-solid polymer electrolyte (PPLCE) was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol) dimethacrylate (PEGDMA) acts as a structural frame, combined with poly(ethylene glycol) diglycidyl ether short chain interspersed serving as mobile ion transport entities. The preparaed PPLCEs exhibit excellent mechanical property and outstanding electrochemical performances, which is attributed to their unique three-dimensional co-continuous structure, characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase, resulting in a distinctive nanostructure with short-range order and long-range disorder. Remarkably, the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs, which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte. When used in a lithium-ion symmetrical battery configuration, the 6 wt%-PPLCE exhibites super stability, sustaining operation for over 2000 h at 30 °C, with minimal and consistent overpotential of 50 mV. The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g−1 at current densities of 0.2 and 1 C, respectively. Even after more than 300 cycles at a current density of 0.2 C, it retaines an impressive 73.5% capacity. Moreover, it displayes stable cycling for over 180 cycles at a high current density of 0.5 C. The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.

Tunable fabric zinc-based batteries utilizing core-shell like fiber electrodes with enhanced deformation durability

One-dimensional (1D) fiber-based batteries stand as a promising route for next-generation wearable devices, owing to their combined energy storage capability and wearability. However, the development of efficient fiber electrodes and high-quality battery configurations that retain excellent electrochemical performance and garment compatibility while withstanding variable mechanical deformations remains a pressing challenge. In this study, NiCo2S4@rGO nanocomposites with stable structures and excellent electrochemical performance were constructed using an in-situ hydrothermal strategy. The highly conductive network of reduced graphene oxide (rGO) improved the electron transport efficiency of the nanocomposites, while mitigating volume changes, structural collapse, and self-aggregation of NiCo2S4 nanoparticles during the charging/discharging cycle. As expected, the nanocomposite cathodes in the Zn-based batteries exhibited remarkable discharging capacity (277.11 mAh g−1) and cycling performance (70% retention after 2000 cycles). Subsequently, a composite fiber cathode (NiCo2S4@rGO-PU-CNTs) with tailorable length and core-shell like structure was fabricated via wet spinning. Benefiting from the introduced carbon nanotubes (CNTs) and polyurethane (PU), the composite fiber cathode formed efficient dual-conducting networks and stable core-shell like structures, thereby improving the electron transport pathways and mechanical flexibility. Finally, as a proof of concept, the independent NiCo2S4@rGO-PU-CNTs cathode and independent Zn@SSY (stainless steel yarn) anode were woven into a knitted fabric, creating tunable serpentine footprint fabric Zn-based batteries with exceptional electrochemical properties (175.29 mAh g−1 and 0.088 mAh cm−1), coupled with remarkable electrochemical stability and mechanical deformation durability. The engineering strategy reported herein provides a promising platform for the quick, facile, and continuous preparation of composite fiber cathodes and tailorable wearable energy textiles.

Ordered planar plating/stripping enables deep cycling zinc metal batteries.

Metal anodes are emerging as culminating solutions for the development of energy-dense batteries in either aprotic, aqueous, or solid battery configurations. However, unlike traditional intercalation electrodes, the low utilization of "hostless" metal anodes due to the intrinsically disordered plating/stripping impedes their practical applications. Herein, we report ordered planar plating/stripping in a bulk zinc (Zn) anode to achieve an extremely high depth of discharge exceeding 90% with negligible thickness fluctuation and long-term stable cycling. The Zn can be plated/stripped with (0001)Zn preferential orientation throughout the consecutive charge/discharge process, assisted by a self-assembled supramolecular bilayer at the Zn anode-electrolyte interface. Through real-time tracking of the Zn atoms migration, we reveal that the ordered planar plating/stripping is driven by the construction of in-plane Zn─N bindings and the gradient energy landscape at the reaction fronts. The breakthrough results provide alternative insights into the ordered plating/stripping of metal anodes toward rechargeable energy-dense batteries.

Improving Sustainability in Urban and Road Transportation: Dual Battery Block and Fuel Cell Hybrid Power System for Electric Vehicles

Improving Sustainability in Urban and Road Transportation: Dual Battery Block and Fuel Cell Hybrid Power System for Electric Vehicles

Argyrodite-Li6PS5Cl/Polymer-based Highly Conductive Composite Electrolyte for All-Solid-State Batteries.

Solid-state batteries (SSBs) that incorporate the argyrodite-Li6PS5Cl (LPSCl) electrolyte hold potential as substitutes for conventional lithium-ion batteries (LIBs). However, the mismatched interface between the LPSCl electrolyte and electrodes leads to increased interfacial resistance and the rapid growth of lithium (Li) dendrites. These factors significantly impede the feasibility of their widespread industrial application. In this study, we developed a composite electrolyte of the LPSCl/polymer to enhance the contact between the electrolyte and electrodes and suppress dendrite formation at the grain boundary of the LPSCl ceramic. The monomer, triethylene glycol dimethacrylate (TEGDMA), is utilized for in situ polymerization through thermal curing to create the argyrodite LPSCl/polymer composite electrolyte. Additionally, the ball-milling technique was employed to modify the morphology and particle size of the LPSCl ceramic. The ball-milled LPSCl/polymer composite electrolyte demonstrates slightly higher ionic conductivity (ca. 2.21 × 10-4 S/cm) compared to the as-received LPSCl/polymer composite electrolyte (ca. 1.65 × 10-4 S/cm) at 25 °C. Furthermore, both composite electrolytes exhibit excellent compatibility with Li-metal and display cycling stability for up to 1000 h (375 cycles), whereas the as-received LPSCl and ball-milled LPSCl electrolytes maintain stability for up to 600 h (225 cycles) at a current density of 0.4 mA/cm2. The SSB with the ball-milled LPSCl/polymer composite electrolyte delivers high specific discharge capacity (138 mA h/g), Coulombic efficiency (99.97%), and better capacity retention at 0.1C, utilizing the battery configuration of coated NMC811//electrolyte//Li-Indium (In) at 25 °C.

Performance analysis and capacity configuration of building energy system integrated with PV/T technology under different operation strategies

Implementing suitable operation strategies significantly enhances the overall performance of the energy network of solar buildings. Previous studies predominantly concentrated on dispatching energy from standalone photovoltaic or photothermal modules within buildings. The photovoltaic/thermal (PV/T) modules have garnered attention due to their higher energy efficiency. However, the investigations targeting the operation strategies of PV/T modules in building remain scarce. To fill this research gap, this study scrutinized the maximum self-consumption (MSC), time-of-use (TOU), and optimization-based (OPT) strategies within a building energy system integrated with PV/T modules. The investigation encompassed an analysis of overall performance, parameter sensitivity, and optimal energy storage capacity. The main results were: (1) The OPT strategy displayed superior flexibility and lower operation costs compared to other strategies but exhibited lower energy utilization efficiency and greater grid impact. (2) The MSC strategy demonstrated lower sensitivity concerning battery power and charge states when contrasted with other strategies. (3) The optimal capacities for battery and water tank configurations for the MSC, TOU, and OPT strategies were identified as 4 kWh/200 L, 2.5 kWh/200 L, and 4.5 kWh/100 L, respectively. This research aims to provide reference and insights for planning the integration of PV/T modules into building energy systems.

Current Progress of Anode‐Free Rechargeable Sodium Metal Batteries: Origin, Challenges, Strategies, and Perspectives

AbstractAnode‐free sodium metal batteries (AFSMBs) as one new battery configuration, have attracted more attention in recent years and considered as the promising next‐generation energy storage systems, owing to the advantages of high theoretical energy density, high safety, cost‐saving, and simplified fabrication process. The practical application of AFSMBs, however, is impeded by their poor cycle life arising from the low coulombic efficiency (CE), the growth of metal dendrite, and unstable solid electrolyte interphase (SEI). Recently, some works are reported to dissolve the above‐mentioned issues. In this review, it provides a comprehensive summary of AFSMBs including their origin, mechanism, advantages, challenges, strategies, and perspectives. First, the intrinsic issues of conventional sodium metal batteries are summarized as safety concerns and manufacturing difficulty, which is the background of promoting AFSMBs’ birth. Subsequently, the mechanism, construction requirement, advantages, and challenges of AFSMBs are discussed. Furthermore, the strategies for improving AFSMBs performance in terms of the current collector, electrolyte, and protocols, are summarized based on an extensive literature survey. Finally, the summary and outlook on this emerging field are further discussed briefly.

The influence of solvent-temperature parameters of sodium titanium phosphate anode materials prepared by sol-gel method

Sodium titanium phosphate (NTP) has garnered significant attention as a promising anode material for sodium ion batteries (SIBs). However, the existing preparation methods still face several challenges that substantially impact the performance of NTP. In order to elucidate the underlying reasons behind the disparate performances resulting from various preparation techniques, this study focuses on the synthesis of carbon-coated NTP via the sol-gel method utilizing different solvents and temperatures. Notably, it was observed that NTP prepared in water at 80 °C exhibited superior crystallinity and purity compared to other solvent-temperature combinations, because of hydrolysis inhibited. The synthesized carbon-coated NTP material demonstrated exceptional electrochemical properties when evaluated as an anode in a half battery configuration. Specifically, even after undergoing 200 charge-discharge cycles at a rate of 1C, the material exhibited a specific capacity of 93 mAh g−1. This work provides valuable insights into the optimization of NTP synthesis methodologies, paving the way for the development of efficient and cost-effective approaches for large-scale production of sodium-ion batteries with improved energy storage capabilities.

Battery configuration dependence to power line communication using high-order quadrature amplitude modulation

Power line communication (PLC) within future smart batteries facilitates the communication of high fidelity sensor data between smart cells and external systems, with application areas including intelligent vehicles and smart grids. This interconnected PLC system of smart cells will enhance cell utilisation and safety through cell-to-cell coordination at a system level, leveraging the existing bus bar within the battery and eliminating the need for additional wire harnesses. This paper studies the performance of a PLC system operating at carrier frequencies of 10MHz to 6GHz within four distinct configurations of lithium-ion batteries. This assessment focuses on changes in scattering parameters and data transmission error ratios. Furthermore, quadrature amplitude modulation (QAM) orders of up to 1024 are investigated for their viability within such environments. The results indicate that the addition of cells in parallel increases error ratios with high-order QAM, and that this effect varies substantially with carrier frequency. Using QAM increases data throughput, allowing for data transfers within large-scale battery systems without PLC bus bandwidth saturation. A prospective centre frequency of 3650MHz allows for a wide bandwidth of 300MHz and 1024-QAM with little signal attenuation and data error. At this frequency, the need for signal repeaters and higher signal output power is reduced. These results are used to determine the most suitable arrangement of cells within a smart battery with consideration of the PLC performance. The preliminary performance of a large-scale battery system with PLC in-situ could be derived from the findings in this research based upon the four battery configurations tested.

Operando Nanomechanical Mapping of Amorphous Silicon Thin Film Electrodes in All-Solid-State Lithium-Ion Battery Configuration during Electrochemical Lithiation and Delithiation.

An operando bimodal atomic force microscopy system was constructed to perform nanomechanical mapping of an amorphous Si thin film electrode deposited on a Li6.6La3Zr1.6Ta0.4O12 solid electrolyte sheet during electrochemical lithiation/delithiation. The evolution of Young's modulus maps of the Si electrode was successfully tracked as a function of apparent Li content x in lithium silicide (LixSi) simultaneously with real-time surface topography observation. At the initial stage of lithiation, the average modulus steeply decreased due to the generation of LixSi from intrinsic Si, followed by a moderate modulus reduction until the electrode capacity reached 3300 mAh g-1 (Li content x = 3.46). In the following delithiation, the gradual recovery of the average modulus of LixSi was observed up to 1467 mAh g-1 (Li content x = 1.54) at which delithiation stopped due to the significant volume change induced by phase transformation of LixSi.

The status and challenging perspectives of 3D-printed micro-batteries.

In the era of the Internet of Things and wearable electronics, 3D-printed micro-batteries with miniaturization, aesthetic diversity and high aspect ratio, have emerged as a recent innovation that solves the problems of limited design diversity, poor flexibility and low mass loading of materials associated with traditional power sources restricted by the slurry-casting method. Thus, a comprehensive understanding of the rational design of 3D-printed materials, inks, methods, configurations and systems is critical to optimize the electrochemical performance of customizable 3D-printed micro-batteries. In this review, we offer a key overview and systematic discussion on 3D-printed micro-batteries, emphasizing the close relationship between printable materials and printing technology, as well as the reasonable design of inks. Initially, we compare the distinct characteristics of various printing technologies, and subsequently emphatically expound the printable components of micro-batteries and general approaches to prepare printable inks. After that, we focus on the outstanding role played by 3D printing design in the device architecture, battery configuration, performance improvement, and system integration. Finally, the future challenges and perspectives concerning high-performance 3D-printed micro-batteries are adequately highlighted and discussed. This comprehensive discussion aims at providing a blueprint for the design and construction of next-generation 3D-printed micro-batteries.

Novel Electrolyte Development for In Situ Formed Li-Metal Batteries Using Amplified Solid Electrolyte Interphase and Plating Investigations

Li-metal anodes can provide high energy density battery configurations, but their practical use is hindered by safety concerns and poor efficiencies due to non-ideal lithium plating. In utilizing ultra-low areal plating capacities (0.08 mAh cm−2, LCP) within Li-metal half-cells, it was found that the initial formation efficiency of the SEI can be amplified and correlated with initial losses and capacity fade over time under higher areal plating capacities (2.5 mAh cm−2, 4.0 mAh cm−2, and 6.5 mAh cm−2) within an in-situ formed anodeless LCO configuration. Herein, these techniques have been utilized to introduce and optimize novel fluoroganosiyl (FOS) based dual salt electrolytes for use in in-situ formed Li-metal batteries, achieving initial cycling loss of <3% (at 4.0 mAh cm−2). Further characterization of the functional benefit of this electrolyte was elucidated using XPS surface analysis, revealing unique Li-C-N, Li3N, Si, and B-N chemistries that likely contribute to the formation of a robust SEI.

Characterizing the Cathode Degradation Process from Thermal Abuse in Solid State Batteries

With an ever-increasing reliance on batteries for all aspects of life, safety of energy storage is a growing concern as reported instances of lithium-ion battery (LIB) fires and even a solid-state battery (SSB) fire arise. However, the understanding of battery safety from a fundamental materials level is not well understood. As the push for higher energy density batteries in the electrification of transportation continues, it is imperative to understand how underlying material degradation and failure affects the safety of current and next-generation lithium battery technology.In this study, heat release and corresponding degradation due to external heating are explored for the following battery configurations: All solid-state batteries (ASSBs), SSBs containing a low amount of liquid electrolyte, and LIBs. NMC532 cathode was used in all battery configurations, Ta-doped LLZO was used for the solid electrolyte, and LiPF6 in EC/EMC was used as the liquid electrolyte in the SSB and LIB configurations. Differential scanning calorimetry (DSC) was used to raise microcells to definitive temperatures of interest depending upon their respective exotherm profile. LIB sample heat release was significantly higher than the heat release of the ASSB and SSB, even though the heating temperature range and final temperature were lower for the LIB samples. The disassembled microcell components were then analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis revealed the LIB samples did not show the presence of the fully degraded rock salt crystalline phase after peak heat release, whereas ASSB and SSB configurations revealed the presence of the rock salt phase. Additionally, SEM image analysis shows no degradation of the LIB particles, while ASSB and SSB samples show surface degradation of the high temperature samples. Decomposition of NMC to the rock salt phase involves the release of oxygen, which may undergo an exothermic reaction inside the SSB. These investigations shed light into the expected extent of NMC decomposition at key temperatures and exothermic heat flow peaks for each battery composition. Future work combining these results with further elemental characterization experiments will pave the way for a materials-level understanding that can be incorporated into the initial design and development stages of next generation lithium batteries, impacting the creation of energy storage devices by ensuring commitment to safety from the ground up.

Uncovering the Effects of Alloy Interfacial Layers in Anode Free Solid-State Batteries

To achieve high energy density and high specific energy in solid state batteries (SSBs), “anode-free” battery configurations have garnered a great deal of interest. Anode-free systems substantially increase volumetric energy density compared to standard Li-ion batteries and lithium metal batteries by removing the graphite anode and excess lithium, respectively. Additionally, manufacturing is simplified in anode-free configurations by removing the need to process lithium metal. However, to advance this technology, it is critical to understand how lithium deposits and strips on current collectors throughout cycling while also investigating methods to spatially control these processes. Previous work which probed the effects of alloy interlayers in liquid electrolyte systems using operando optical microscopy has found that silver thin films enable higher Coulombic efficiencies (CEs) than bare current collectors and cause different deposition and stripping dynamics1. Silver layers have also shown beneficial effects in enabling long-term cycling of SSBs2, but there is a lack of knowledge regarding the mechanisms by which they improve performance. Here, we investigate the structural and morphological evolution of alloy interlayers in SSBs using cryogenic and plasma focused ion beam (cryo-FIB, PFIB) methods correlated with electrochemical measurements. Improved CEs and cycling stability are observed when using silver and gold interlayers compared to bare copper. The origin of these performance improvements are investigated using cryo-FIB and PFIB to uncover morphology evolution at the solid-state interface. We observe non-uniform lithium growth on bare copper throughout cycling, while uniform lithium growth is observed in silver- and gold- modified interfaces. Interestingly, the silver and gold interlayers undergo different morphological evolution, which affects cycling behavior. Electrochemical impedance spectroscopy (EIS) is used to understand and investigate the influence of the alloy interlayers on interfacial impedance during cycling, which is correlated to morphology evolution. Over the first five cycles, bare copper electrodes exhibit a relatively large increase in impedance while the alloy-modified interfaces exhibit only minor increases in impedance throughout cycling. Furthermore, operando EIS measurements show distinct signatures due to contact loss for the bare copper while contact is retained for alloy-modified interfaces. This work provides new understanding of the mechanisms governing the behavior of alloy interlayers in anode-free SSBs, which is important for engineering high-performance and high-energy devices. Sandoval, S. E. et al. Understanding the Effects of Alloy Films on the Electrochemical Behavior of Lithium Metal Anodes with Operando Optical Microscopy. J. Electrochem. Soc. 168, 100517 (2021).Lee, Y. G. et al. High-Energy Long-Cycling All-Solid-State Lithium Metal Batteries Enabled by Silver–Carbon Composite Anodes. Nat. Energy 5, 299–308 (2020).

Surfactant-Assisted Synthesis of FeF3 • 0.33 H2o and Its Application As Cathodic Material for Electrochemical Energy Storage Devices: From Lithium to Fluoride-Ion Batteries

New generation of electrochemical energy storage devices is needed to face the continuous increase in energy stored capacity demand at lower costs from human society. Moreover, due to the constant increase in number of batteries produced, the development of more sustainable devices without the consumption of limited resources at affordable costs is an actual research challenge. The conventional lithium batteries, the most widespread kind of electrochemical energy storage devices, made by an intercalation cathode (e.g., LiCoO2, LiFePO4) and a graphite anode suffer of limited capacity for high-performance application (such as in electric vehicles) and use limited mineral resources with adverse environmental consequences.Iron fluoride is a promising conversion cathode for positive electrodes in next-gen lithium batteries due to its low cost, great abundance, and ease of extraction1,2. The main problems of metal fluoride-based cathodes are the low conductivity and the structural changes during charge/discharge cycles that limit device capacity and lifespan. To effectively increase the storage capacity, several attempts to use metal lithium anodes have been made. However, this solution is now limited to primary batteries because of dendrites growth during metal plating that causes capacity fading and safety concerns.In the last decade, batteries based on fluoride-ion shuttling are drawing attention3,4 due to the possibility to use a high-capacity conversion cathode, exploiting a multi-electron transfer, and a metal anode without dendrites formation. This kind of devices, in the early stage of development, rely on electrochemical fluorination of an electropositive metal anode and the defluorination of a more “noble” metal fluoride without a metal plating-stripping process. Nowadays, electrolyte limitation is the main challenge for the development of a fluoride-ion battery that can compete with state-of-the-art lithium-ion batteries.In this work, a surfactant-assisted solvothermal route to obtain iron fluoride hydrate (FeF3 0.33 H2O) is presented. A hierarchical grape-like structure was obtained and it was tested as cathode active material in a 2025 coin-cell working in a metal-lithium battery configuration. In these tests it showed improved performance, compared to the same synthesis without surfactant. The synthetized material was also characterized by morphological and electrochemical point of view by means of Electrochemical Impedance Spectroscopy (EIS), galvanostatic charge discharge (GCD) and cyclic voltammetry (CV).The possibility to use the same cathodic material in a room-temperature fluoride-ion battery with a metal anode was assessed by using fluoride conducting liquid electrolytes5: encouraging results about the feasibility were achieved; however, further research in the field of liquid electrolytes resulted fundamental for bringing performances of this technology to the level of actual lithium batteries.

Investigating the Reaction Mechanism of Vinylene Carbonate Additive in Lithium Ion Batteries Using X-Ray Photoelectron Spectroscopy

The rechargeable Li-ion battery is an enabling technology which facilitates the electrification of the automotive industry and reduces the demand for fossil fuels. During the charge and discharge of a battery, a solid-electrolyte interphase (SEI) forms between the liquid electrolyte and the solid negative electrode as a result of electrolyte degradation. The chemical and physical stability and the functionality of the SEI is a key determining factor of battery performance. The chemical composition of the SEI is mainly controlled by the choice of solvent and salt used, but can be manipulated by the addition of electrolyte additives that influence the electrolyte degradation process.Vinylene carbonate (VC) is an additive used in many commercial Li-ion battery configurations. The addition of a small amount of VC to ethylene carbonate (EC) containing electrolytes has been demonstrated to drastically improve several performance metrics for batteries including cycle life, coulombic efficiencies, capacity retention and thermal stability. The success of VC is widely attributed to its ability to form a thinner, denser and more robust SEI, which better protects the electrode surface and prevents further electrolyte consumption. This improvement in stability has been linked to the presence of poly(VC) in the SEI, but the mechanism by which VC reacts in EC-containing electrolytes is still an area of ongoing study. Whilst computational methods have suggested several potential decomposition pathways of electrolytes containing VC, it is yet to be convincingly demonstrated experimentally. Whilst there is a general consensus about ‘What?’ forms in the SEI on the addition of VC to EC-containing solvent, this work aims to confirm ‘Where?’ these components are in the interface and the currently unanswered questions of ‘How?’ and ‘Why?’ they form.Using highly surface sensitive photoelectron spectroscopy (PES) measurements of the SEI deposited at various potentials, we identify the differences in composition and structure that result from the addition of VC additive to EC-containing electrolytes. The SEI formation is studied using a smooth Au surface as the model working electrode and a fluorine free EC:diethyl carbonate (DEC) (1:9) 1 M LiClO4 electrolyte in an attempt to isolate the impact of VC on the SEI. A potential step procedure allows analysis of the working electrode surface by PES at several progressively more negative potentials on the first charge. Through systematic variation of components such as the concentration of VC, the ratio of EC:DEC and swapping Au for other electrode materials such as Cu or Si, the interaction between VC, EC and the electrode surface is revealed. The differences in SEI composition and structure formed in each environment and at each potential step are correlated to quartz crystal microbalance (QCM) data in order to identify potential reaction mechanisms and formation processes. The results play a key role in understanding the reaction pathway of VC-containing electrolytes and will accelerate development of more efficient electrolyte additives.

Understanding the Phase Transitions in Tin Foil Electrodes for Sodium-Ion Batteries through Light Microscopy and Kinetic Analysis

Group IVA elements exhibit some interesting sodium capabilities via electrochemical alloying processes (except carbon). Among them, tin is believed to be the most promising anode candidate for sodium-ion batteries (SIBs) due to its simple fabrication and monolithic form (e.g., metallic foils).[1] Nevertheless, tin foil anodes usually fail prematurely after only a handful of cycles. This poor reversibility is reported to be largely associated with the structural collapse of tin electrodes caused by huge volume differences among various Na-Sn phases (up to ~420%).[2][3] The volume change and the number of stress-induced cracks during different phase transitions can be different, given that these intermediate sodium-containing tin phases have different crystal structures and mechanical properties.[4] To prolong the lifetime of tin foil electrodes, it is crucial to determine which phase transitions have a greater impact on crack formation in the tin electrode and deliberately mitigate the problematic phase transitions.In this work, the mechanisms and kinetics of the phase transitions that occur in the sodiation of tin foil are extensively investigated using operando light microscopy and robust electrochemical techniques. Ex situ X-ray diffraction (XRD) (Figure 1) reveals that the initial sodiation of tin foil begins with a significant crystalline to amorphous transition (i.e., c-Sn to a-NaSn), followed by the a-NaSn to c-Na9Sn4 and the c-Na9Sn4 to c-Na15Sn4 transitions. To further understand these transitions, we introduce a new battery configuration for light microscopy to observe the dynamic change of the cross-section macrostructure of tin foil electrodes during cycling. It is expected that the observation could partly quantify the volume expansion during different phase transitions, directly visualize the formation of cracks, and accurately estimate the sodium diffusion coefficient in tin foil electrodes. Moreover, the change of charge transfer resistance as a function of sodiation depth is measured using electrochemical impedance spectroscopy (EIS), shedding light on the degradation mechanism. Besides, potentiostatic intermittent titration technique (PITT) is also employed to determine the role of diffusion or interfacial charge transfer on the whole kinetics of tin anode at different depths of discharge. These investigations could yield fundamental insights into the sodiation mechanisms and kinetics of tin foil electrodes, and more importantly, provide guidance for the utilization of binder- and additive-free tin foil as a reliable SIB anode. Figure 1

Smart Design of Wireless Data Transmission Employing Solar-Powered IOT Devices

This study emphasizes the expanding need for solar energy extraction over the past few decades and focuses on the crucial role that solar photovoltaics (PV) play in the renewable energy environment. The surge in demand has driven attention toward enhancing monitoring technologies to maximize their efficiency. The paper introduces a novel wireless platform aimed at augmenting the monitoring of solar PV systems. This innovative approach enables wireless data transmission from a diverse array of sensors and nodes, addressing various challenges, including data volume management, potential signal interference, long-distance data transfer requirements, and data security concerns. The research findings underline the necessity of a minimum 14 Ah battery capacity to accommodate seasonal fluctuations in solar irradiation. A crucial aspect of the study lies in the implementation of an adaptive power system, which significantly alleviates the demand for batteries when the state of charge falls below 30%. This adaptive system not only ensures cost-effective data transmission rates but also offers the potential to maintain system functionality with smaller battery and solar panel configurations. Additionally, it enhances reliability under varying light conditions, mitigating the risk of system failure.