Free-standing Electrode Research Articles

Battery-Type Desalination Behavior Confined Within Capsules for Efficient Capacitive Deionization.

Battery-type faradaic materials are considered a class of promising electrodes for capacitive deionization (CDI) due to their superior ability to store ions through redox reactions. However, the desalination potential of such electrode materials has not been fully explored subject to the accessibility, conductivity, stability, etc. Herein, embedded battery material Ag nanoparticles is designed in capsule-structural units composed of graphene and constructed freestanding composite electrodes for CDI. Particularly, these Ag nanoparticles confined in interconnected graphene capsules can be both efficiently accessed by the electrolyte and rationally protected by the capsule networks, significantly unlocking their potential as desalination materials. Impressively, the optimized Ag-involved anodes can achieve an ultrahigh NaCl desalination capacity of ≈360 mg g-1 (≈218 mg g-1 for Cl-) at 1.4 V and exhibit good cycling stability. Moreover, the as-designed anodes also have very competitive desalination capacities for other anions, such as SO2- 4 (≈90 mg g-1) and CrO2- 4 (≈77 mg g-1), suggesting the broad applicability of such Ag-involved electrodes. This work shows that the ingenious introduction of space-confined structures is an effective means of unlocking the desalination potential of Ag-based materials, opening up alternative avenues for the development of other high-performance battery-type desalination electrodes.

Self-supported electrochemical sensor based on uniform palladium nanoparticles functionalized porous graphene film for monitoring H2O2 released from living cells.

Graphene film has been considered a promising material for the construction of self-supported electrodes due to its favorable flexibility and high conductivity. However, the film fabricated from pristine graphene or conventional graphene sheet reduced graphene oxide processes limited electrocatalytic performance. Decorating active metal species or incorporating heteroatoms intothegraphene framework have been proved to be effective methods to enhance the electrocatalytic efficiency of graphene film-based self-supported electrodes. Herein, we present a freestanding electrode composed of uniform Pd nanoparticles decorating N,S co-doped porous graphene film (Pd/NSPGF) and explore its practical application in differentiating various human colon cell types by in situ tracking the amount of H2O2 secreted from live cells. Our findings reveal that, on the one hand, the NSPGF has abundant surface and inner pores, which promote active site exposure, and mass diffusion during electrochemical reactions; on the other hand, the substitutional doping ofthe graphene framework with heteroatoms (e.g., N or S) can tailor its electronic and chemical properties, and facilitate the uniform loading of high-density Pd nanoparticles. Moreover, the intrinsic activity of Pd/NSPGF is regulated by the interaction of Pd nanoparticles withtheNSPGF support. Taking the advantages of morphology and composition, the self-supported Pd/NSPGF electrode displays remarkable electrochemical performance with a wide linear range up to 2.0mM, low detection limit of 0.1μM (S/N = 3), high sensitivity of 665 µA cm-2mM-1, and good selectivity. When applied in real-time trackingofthe H2O2 released from normal human colon epithelial cells and human colorectal cancer cells, the Pd/NSPGF-based electrochemical sensing system can distinguish the cell types by testing the number of extracellular H2O2 molecules released per cell, which holds considerable potential for early detection and monitoring of disease-related clinical specimens.

Facile Synthesis of flexible free-standing electrode for high energy density batteries by using PTMSP as binder

As a crucial component of the electrode, the binder greatly impacts battery performance. Herein, we report a novel binder, poly[1-(trimethylsilyl)-1-propyne] (PTMSP), which enables the construction of flexible free-standing electrodes for high performance lithium-ion batteries. The free-standing electrodes based on the PTMSP binder demonstrate remarkable cycling performance in various electrode materials, including LFP, S, and LTO, demonstrating significant potential for market application.

Development of a free-standing flexible electrode for efficient overall water-splitting performance via electroless deposition of iron-nickel-cobalt on polyacrylonitrile-based carbon cloth

Developing cost-effective and highly efficient electrodes for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is crucial, particularly for alkaline OER and HER. Herein, electroless plating of iron-nickel–cobalt (Fe–Ni–Co) electrocatalyst on a flexible polyacrylonitrile (PAN)-based carbon cloth (CC) was performed to synthesize a free-standing catalytic electrode for bifunctional electrocatalysts. The three-dimensional porous backbone of PAN-based CC and the synergistic effect between Fe-Ni-Co and corresponding hydroxides result in outstanding OER and HER activities, that is low overpotentials of 230 and 150 mV at 10 mA cm−2 and Tafel slopes of 63 and 57.1 mV dec–1, respectively. Additionally, a complete alkaline electrolyzer was constructed using Fe-Ni-Co plated PAN-based CC as both the cathode and anode. When operated at 10 mA cm−2, this setup enabled efficient water splitting at a low potential of 1.57 V. This study provides new opportunities for the development of advanced Fe-Ni-Co electrocatalyst with superior bifunctional OER and HER performance and cost-effectiveness that are suitable for integration into PAN-based CC via electroless plating.

Significantly enhanced electrochemical performance of Al-Ti3C2Tx MXene synthesized from Al-Ti3AlC2 MAX phase

MXenes, a type of two-dimensional nanomaterials consisting of transition metal carbides/nitrides, have emerged as promising electrode materials for supercapacitors. Especially, Ti3C2Tx MXene prepared from Ti3AlC2 MAX phase shows great application potential in flexible supercapacitors due to its facile synthesis, excellent conductivity and film-forming property. In contrast to conventional Ti3AlC2, excessive aluminum is incorporated in the synthesis process to produce Al-Ti3AlC2. In this study, Ti3AlC2 and Al-Ti3AlC2 MAX phases are used to synthesize Ti3C2Tx and Al-Ti3C2Tx MXenes, respectively, by the same method of HF:HCl etching and LiCl intercalation. The freestanding Ti3C2Tx and Al-Ti3C2Tx film electrode is separately prepared through simple vacuum filtration. The presence of excess aluminum during the Al-Ti3AlC2 synthesis facilitates to form more homogeneous grains structure with relatively larger particle sizes and an improved stoichiometric MAX phase with a Ti:C ratio closer to 3:2. The resulting Al-Ti3C2Tx nanosheets show improved oxidation resistance with relatively uniform and larger dimensions, which facilitate the higher conductivity with slightly increased interlayer spacing for the Al-Ti3C2Tx film. Therefore, the Al-Ti3C2Tx film electrode shows more efficient ions transport and charge transfer, and thus achieves significantly enhanced capacitance (399 F g−1 at 1 A g−1) and rate performance (63.6 % retention from 1 to 10 A g−1) compared to the Ti3C2Tx film electrode (342 F g−1 at 1 A g−1, 55.6 % retention from 1 to 10 A g−1). Moreover, the Al-Ti3C2Tx-based flexible sandwiched supercapacitor also exhibits superior energy storage performance. The impressive results indicate that Al-Ti3C2Tx MXene synthesized from Al-Ti3AlC2 MAX phase possesses the great application potential in flexible supercapacitors.

In situ anchoring of FeNi nanoparticles into three-dimensional nitrogen-doped carbon framework as a self-supporting electrode for high-performance lithium storage

Constructing free-standing electrodes with superior lithium storage capacity and good mechanical performance are fascinating for next-generation lithium-ion batteries (LIBs). Nevertheless, their practical application is hindered by complicated synthesis procedures and high cost. Herein, a highly stable, self-supporting and flexible electrode material for LIBs was constructed by encapsulating spherical FeNi nanoparticles into one-dimensional N-doped carbon fiber film (FeNi/N- CFM) using the electrospinning technique and subsequent heat treatment. The FeNi/N-CFM can be directly used as anode materials for LIBs without conductive additive, current collector and binder. The synergistic effect of uniformly dispersed small FeNi nanoparticles and three-dimensional (3D) conductive network constructed by CF framework effectively improves the utilization rate of active materials, enhances the transport of both electrons and lithium ions, facilitates the electrolyte penetration, and promotes the lithium-ion storage kinetics and stability, thus leading to a greatly enhanced electrochemical performance. Benefiting from the unique architectural feature and flexibility, the FeNi/N-CFM composites employed as binder-free electrodes for LIBs exhibit good lithium storage performance (an initial discharge capacity of 1031.5 mA h g−1 and a reversible capacity of 481.3 mA h g−1 at 100 mA g−1 after 100 cycles), rate capacity (305.1 mA h g−1 at 1000 mA g−1) and outstanding reversibility (coulombic efficiency of around 100 % after 100 cycles). Furthermore, this work also provides a facile and effective pathway to design and fabricate free-standing electrodes.

Roller-like Spore Carbon Sphere-Orientated Graphene Fibers Prepared via Rheological Engineering for Lithium Sulfur Batteries.

Flexible batteries with large energy densities, lightweight nature, and high mechanical strength are considered as an eager goal for portable electronics. Herein, we first propose free-standing graphene fiber electrodes containing roller-like orientated spore carbon spheres via rheological engineering. With the help of the orientated microfluidic cospinning technology and the plasma reduction method, spore carbon spheres are self-assembled and orientedly dispersed into numerous graphene flakes, forming graphene fiber electrodes enriched with internal rolling woven structures, which cannot only enhance the electrical contact between active materials but also effectively improve the mechanical strength and structure stability of graphene fiber electrodes. When the designed graphene fibers are combined with the active sulfur cathode and lithium metal anode, the assembled flexible lithium sulfur batteries possess superior electrochemical performance with high capacity (>1000 mA h g-1) and excellent cycling life as well as good mechanical properties. According to density functional theory and COMSOL simulations, the roller-like spore carbon sphere-orientated graphene fiber hosts provide reinforced trapping-catalytic-conversion behavior to soluble polysulfides and nucleation active sites to lithium metal, thus synergistically suppressing the shuttle effect of polysulfides at the cathode side and lithium dendrite growth at the anode side, thereby boosting the whole electrochemical properties of lithium sulfur batteries.

Electrostatic Interactions Dominate the Surface Assembly of Silicon‐Based Nanospheres on Carbon Nanofibers for Flexible Lithium‐Ion Batteries

AbstractThe construction of flexible freestanding silicon‐based electrodes eliminates the addition of inactive materials, improving the overall energy density, and effectively avoiding the disadvantage of active materials being easily separated from the collector due to the volume effect. However, many reports of flexible freestanding electrodes lack long‐term cycling stability. Here, 3 different silicon‐based freestanding electrodes are designed and find that the freestanding electrode with surface assembly dominated by electrostatic interactions can significantly improve long‐term cycling stability. Owing to better mechanical properties, this surface‐assembled electrode demonstrates unique flexibility. The conductive framework and unique void structure not only reveal the excellent lithium‐ion diffusion capability and charge‐transfer kinetics but also provide ample space for the volume expansion of the silicon‐based material, which endows electrodes with excellent electrochemical performance. With 2 folds, the capacity remains at 471 mA h g−1 after 1000 cycles (0.5 A g−1). In addition, the as‐prepared flexible pouch cell maintains high capacity and cycling stability after folding, with an average capacity degradation of only 0.01% per cycle during 1000 cycles, highlighting its considerable potential in the development of flexible devices. Remarkably, such interfacial assembly on the fiber surface also enables the modulation of multilayer assembly.

Role of Nitrogen-doping in porous carbon for enlarging working voltage window of aqueous supercapacitors in neutral electrolyte

The fundamental mechanism on enlarging working voltage window of carbon-based aqueous supercapacitors is still unclear owing to the indistinct principles in inhibiting water splitting occurred at the electrochemical interface. Herein, we design a set of N, O co-doped porous carbon (NOPC) free-standing electrodes with adjustable N-doping level, and establish that N-doping (N-content and specific N-configuration) governs neutral HER and OER. The NOPC electrode with a lower N-doping level can possess a wide working potential window of − 1–1 V, and thus the corresponding aqueous symmetric supercapacitors showcase a wide working voltage window of 2 V in LiCl aqueous solution. In situ spectroscopy evidences and theoretical simulation demonstrate that the low N-doping (N-content and percentage of pyrrolic nitrogen) level can weaken the interaction between the electrode and interfacial water molecules and suppress the formation of *OOH intermediate during the charge–discharge process, and thus significantly decreasing the HER and OER activities to inhibit water splitting. The finding can shed light on the fundamental understanding of mechanism on enlarging working voltage window of carbon-based aqueous supercapacitor.

Effect of processing parameters on the properties of carbon paper as a free-standing supercapacitor electrode

As newly emerging energy storage devices, supercapacitors are being investigated thoroughly by researchers. Free-standing electrode is one of the major research focuses in this area, which not only avoids the use of resistive binders but also simplifies device assembly. The study describes the synthesis and study of carbon fiber-based carbon carbon composite paper (heat treated to different temperatures) as a free-standing supercapacitor electrode. Due to the inert nature of carbon paper, it was activated to create defect sites and to increase the specific surface area. Electrochemical studies suggested that activated carbon paper heat treated to 750°C (ACP-750) exhibited the highest areal capacitance of 11.4 F/cm2 (422.2 F/g) at the current density 2.5 mA/cm2 (0.09 A/g), probably due to the generation of larger number of defect sites (as depicted by XRD and RAMAN studies). ACP-750 electrode was used to fabricate the solid-state symmetric supercapacitor device that exhibited an energy density 0.77 Wh/cm2 at a power density of 2.34 W/cm2. The electrode was allowed to age (ACPA-750), after which it exhibited enhanced specific capacitance of 16.8 F/cm2 (622.2 F/g) at a current density 2.5 mA/cm2. ACPA-750//ACPA-750 device delivered maximum energy density of 1.66Wh/cm2 at a power density of 3 W/cm2. The device exhibited a coulombic efficiency of 96.1% and capacitance retention of 89% after 10,000 cycles.

Self-Thermal Management in Filtered Selenium-Terminated MXene Films for Flexible Safe Batteries.

Li-ion batteries with superior interior thermal management are crucial to prevent thermal runaway and ensure safe, long-lasting operation at high temperatures or during rapid discharging and charging. Typically, such thermal management is achieved by focusing on the separator and electrolyte. Here, the study introduces a Se-terminated MXene free-standing electrode with exceptional electrical conductivity and low infrared emissivity, synergistically combining high-rate capacity with reduced heat radiation for safe, large, and fast Li+ storage. This is achieved through a one-step organic Lewis acid-assisted gas-phase reaction and vacuum filtration. The Se-terminated Nb2Se2C outperformed conventional disordered O/OH/F-terminated materials, enhancing Li+-storage capacity by ≈1.5 times in the fifth cycle (221 mAh·g-1 at 1 A·g-1) and improving mid-infrared adsorption with low thermal radiation. These benefits result from its superior electrical conductivity, excellent structural stability, and high permittivity in the infrared region. Calculations further reveal that increased permittivity and conductivity along the z-direction can reduce heat radiation from electrodes. This work highlights the potential of surface groups-terminated layered material-based free-standing flexible electrodes with self-thermal management ability for safe, fast energy storage.

Free-standing snowflake-like Mn-doped ZnO@CoCo2O4 nanofilm boosting cycle stability and energy density of supercapacitor

CoCo2O4 is considered as one of the most promising electrode materials owing to its inherently electrochemical performance and low cost. Nevertheless, the further practical application of CoCo2O4 as high-performance electrode material is hindered by its weak cycle stability. Herein, a free-standing snowflake-like Mn-doped ZnO@CoCo2O4 (MZCC) nanofilm is synthesized via hydrothermal method. The unique snowflake structure of this nanofilm composite exhibits obviously large specific surface area, thus promoting the redox reaction of the electrode material. The specific capacitance of the MZCC attains 1245F g−1 at 0.5 A/g. Furthermore, the assembled supercapacitor device with the MZCC and active carbon shows an energy density of 25.7 Wh kg−1 at a power density of 400 W kg−1. The device also demonstrated intriguingly outstanding cyclic stability, maintaining its original specific capacitance of 80.1 % after 3000 cycles at 2 A/g. This study delivers an effective method to construct high-performance free-standing metal oxide nanofilm electrodes for advanced supercapacitors.

Freestanding molybdenum carbide nanowires electrode for high specific capacity and superior rate performance Li–CO2 batteries

Li–CO2 batteries have attracted wide attention owing to unique CO2 capture ability and potential power source for Mars exploration. However, the practical application of Li–CO2 batteries are severely restricted by the sluggish reaction kinetics of 4–electron Li2CO3 as discharged products. Herein, we design efficient freestanding Mo2C nanowires electrode following low electron Li2C2O4–product route to achieve high–performance Li–CO2 batteries. More importantly, we propose a regulation and evolution mechanism of discharge products Li2C2O4 and Li2CO3 on Mo2C cathode in Li–CO2 battery with different discharge depths. Based on reasonable regulation of discharge products, Li–CO2 batteries with the Mo2C nanowires exhibit excellent electrochemical performance with an ultra–low overpotential 0.35 V at 0.05 mA cm–2 and a cycle life of 165 cycles below charge potential of 3.8 V. The Mo2C nanowires electrode also delivers high discharge capacity of 8.47 mAh cm–2 and superior rate capability compared to a conventional Mo2C cathode reported. Moreover, the superior flexibility and stability of the binder–free Mo2C nanowires electrode under different deformations assists in the development of wearable Li–CO2 batteries with safety and sustainability.

Ruthenium Anchored Laser-Induced Graphene as Binder-Free and Free-Standing Electrode for Selective Electrosynthesis of Ammonia from Nitrate.

Developing effective electrocatalysts for the nitrate reduction reaction (NO3RR) is a promising alternative to conventional industrial ammonia (NH3) synthesis. Herein, starting from a flexible laser-induced graphene (LIG) film with hierarchical and interconnected macroporous architecture, a binder-free and free-standing Ru-modified LIG electrode (Ru-LIG) is fabricated for electrocatalytic NO3RR via a facile electrodeposition method. The relationship between the laser-scribing parameters and the NO3RR performance of Ru-LIG electrodes is studied in-depth. At -0.59 VRHE, the Ru-LIG electrode exhibited the optimal and stable NO3RR performance (NH3 yield rate of 655.9µgcm-2h-1 with NH3 Faradaic efficiency of up to 93.7%) under a laser defocus setting of +2mm and an applied laser power of 4.8W, outperforming most of the reported NO3RR electrodes operated under similar conditions. The optimized laser-scribing parameters promoted the surface properties of LIG with increased graphitization degree and decreased charge-transfer resistance, leading to synergistically improved Ru electrodeposition with more exposed NO3RR active sites. This work not only provides a new insight to enhance the electrocatalytic NO3RR performance of LIG-based electrodes via the coordination with metal electrocatalysts as well as identification of the critical laser-scribing parameters but also will inspire the rational design of future advanced laser-induced electrocatalysts for NO3RR.

Utilizing FeS2 Deposition on 3D Printed Carbon Microlattices as Free-Standing Electrodes in Lithium-Ion Batteries

Free-standing electrodes are a great alternative to slurry-coated battery electrodes as they eliminate the need for inactive components and shorten the fabrication process. In this work, carbon microlattice templates are designed and fabricated through the use of 3D stereolithography followed by pyrolysis to create a well-defined carbon template with a resolution >35 µm. Iron disulfide, a material with a high specific theoretical capacity, is then deposited on the surface and used as electrode material in lithium-ion batteries. To date, there have been no reports of FeS2 combined with 3D printed free-standing electrodes. The design utilizes controlled microchannels along the thickness direction to facilitate efficient ion transfer and interconnected carbon skeletons for electron transfer throughout the entire electrode. When directly applied in a lithium-ion battery, the composite material displayed a specific capacity of 562.5 mAh g-1 after 200 cycles with a current density of 500 mA g-1. A high-rate capability was also achieved. Stepwise cyclic voltammetry and Dunn Method confirm that the dominant mechanism guiding the excellent electrochemical performance is diffusion-controlled process, further highlighting the benefits of the organized microchannels. These results will advance the development of composite electrodes as well as shine light on the immense potential to develop high energy density batteries utilizing 3D printing, advocating for sustainable energy from both a research-driven and practical stance.

The Impact of PTFE:PVDF Ratio on the Fabrication of Free-Standing Electrodes for Solvent-Free Dry Electrodes in Libs

The current wet process of LIB electrode fabrication presents several challenges, including the use of the environmentally toxic and harmful N-methyl-2-pyrrolidone (NMP) solvent and non-uniform binder distribution due to the capillary force of the drying process. In addition, it is difficult to increase the thickness of the electrode and leads to relatively low-capacity electrodes. To address these issues, solvent-free dry electrode processes are promising. In the dry electrode process, binders play crucial roles in free-standing electrode formation. Fibrillization of Polytetrafluoroethylene(PTFE) occurs at a temperature of about 19 ℃, and the shear force of high temperature and high pressure helps to maintain the shape of the free-standing electrode.In this study, we performed a comparative analysis through the physical blending of PTFE and PVDF polymer binders with different ratios. A variety of characterization tools are used to investigate the optimal ratio that ensures good cycle performance for high-loading cathode electrodes while maintaining free-standing electrodes: 180° peel test, sheet-resistance test, SAICAS, FE-SEM, and electrochemical performance tests Keywords: Solvent-free, Dry electrode; electrode fabrication; PTFE polymer binder, Fibrillization, Lithium ion batteries Figure 1

Date Seed-Derived Supercapacitor Electrodes in Aqueous Electrolyte: Unveiling High Capacity and Coulombic Efficiency

Date seeds, often considered byproducts of date fruit processing, represent a significant bio-waste stream. Despite their abundance, these seeds are underutilized and typically regarded as agricultural waste. Rich in carbon content, date seeds have the inherent potential to serve as precursors for hard carbon electrodes in supercapacitors. Free-standing electrodes were fabricated to enhance cyclic stability and improve Coulombic efficiency, showcasing superior electrochemical performance. The activation process with a 1:3 KOH-to-bio-char ratio yielded a specific capacitance of 204 F/g at 0.2A/g for the symmetric cell with an energy density of 6.5 Wh/kg and a power density of 47.70 W/kg, highlighting the effectiveness of this approach in advancing both structural integrity and electrochemical attributes. To elucidate the electrochemical performance of KOH-activated hard carbon, BET analysis, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Raman Spectroscopy were employed. BET analyses revealed a higher surface area for the hard carbon activated with a 1:3 KOH ratio. This enhancement in structural integrity was further corroborated by cyclic voltammetry (CV) and charge-discharge curves, emphasizing the favorable electrochemical attributes of the proposed method. While previous investigations into date seed supercapacitors revealed promising results, achieving near 100% Coulombic efficiency remained challenging. In this study, the implementation of free-standing electrodes marked a significant advancement, resulting in a remarkable Coulombic efficiency of 99.97%. This nuanced approach underscores the effectiveness of our methodology in addressing and improving the Coulombic efficiency of date seed-derived supercapacitors.

The Effects of Temperature and Fluoroethylene Carbonate Concentration on the Formation of the Graphite SEI and Its Impact on the Full-Cell Performance

Extending the cycle-life of state-of-the-art lithium-ion batteries (LiBs) is, amongst other aspects, predicated on optimizing the properties of the solid electrolyte interphase (SEI), such as its stability and resistance.[1] It is formed at the negative electrode during the first cycles by electrolyte decomposition and acts as a passivating layer between the electrode surface and the electrolyte.[2,3] Since the SEI formation is accompanied by an irreversible loss of cyclable lithium, its stability during cycling is crucial for improving the charge/discharge efficiency of LiBs. Furthermore, the arising resistance associated with the SEI formation, predominantly depending on the SEI thickness, its chemical composition, and its lithium-ion conductivity, all impact the rate performance of the anode.[4] Two of the most crucial factors impacting SEI formation are temperature and electrolyte composition (i.e., using electrolyte additives).[5] Additives are added to the electrolyte to inhibit the predominant reduction of other electrolyte constituents and thereby form an SEI with improved stability during cycling.[1,6,7] One of the most prominent additives for LiBs is fluoroethylene carbonate (FEC), which is preferentially reduced compared to common carbonate solvents (e.g., ethylene carbonate, ethyl methyl carbonate) due to its higher reduction potential.[7] In this study, we investigated the influence of the formation temperature between 10 and 60 °C, as well as the concentration of FEC (2 and 20 %wt in EC:EMC 3:7 wt/wt with 1 M LiPF6, Gotion, USA) on the characteristics of a synthetic graphite (SMG-A5, Resonac, Japan) anode, both in SMG/Li half-cells and in Ni-rich NCM/SMG full cells.We quantified the first-cycle irreversible capacity loss (ICL) in SMG/Li half cells with a lithium reference electrode after two 0.1 C formation cycles and compared the FEC containing electrolytes to the baseline- (LP-57) and an LP-572 (1 M LiPF6 in EC:EMC 3:7 wt/wt + 2 %wt vinylene carbonate (VC), Gotion, USA) electrolyte. Employing electrochemical impedance spectroscopy in an SMG/Li half-cell setup with a µ-reference electrode and a free-standing graphite electrode,[8,9] we could further quantify the intercalation resistance (R Int, representing the sum of the charge-transfer and the SEI resistance) after an identical formation protocol at 40 % SOC. Both quantities, the ICL and R Int, increase with increasing formation temperature and higher FEC content.The impact of an increasing R Int on the rate performance was tested in Ni-rich NCM/SMG full cells with a lithium reference electrode, revealing a decreased rate capability and higher susceptibility for lithium plating for cells that were formed at higher temperatures and contained 20 %wt FEC. Additionally, the cycling stability of Ni-rich NCM/SMG full cells at 25 °C was assessed in coin cells. Despite an increased ICL and R Int after formation, cells that were formed at elevated temperatures and contained 20 %wt FEC showed enhanced cycling stability compared to those that were formed at a lower temperature and contained less FEC.Finally, on-line electrochemical mass spectrometry (OEMS) was employed to quantify the evolved gases during the formation of a Ni-rich NCM/SMG full cell containing either of the FEC-containing electrolytes at different temperatures. In accordance with an increased ICL and R Int, a higher formation temperature, as well as a higher FEC content, gave rise to a more pronounced gas evolution during formation.

Electrochemical Analysis Comparison of Nitrogen Undoped and Doped Ti3C2Tx/Co3O4 Hybrid Composites on Carbon Cloth for Application as Electrode in Supercapacitor

Supercapacitor provides great potential for good energy storage devices application, compared with other energy storage such as rechargeable batteries, fuel cell, dielectric capacitors and so on. Freestanding and flexible electrodes are vital for the development of flexible and wearable devices that store energy. But the significant trade-off between mechanical flexibility and electrode electrochemical performance limits the fabrication of efficient energy storage systems. In this research, we report the synthesis of a 2D material Ti3C2Tx and Co NPs on carbon cloth (CC) substrate. Co NPs was synthesized by microplasma reactors which eliminate harmful reducing agents and are efficient and cost-effective. And the Co NPs/Ti3C2Tx were synthesized by hydrothermal method for supercapacitor. These materials were characterized by scanning electron microscopy (SEM) Energy Dispersive Spectroscopy and X-Ray Diffraction for morphology and phases analysis. Besides these Transmission electron microscopies (TEM) and X-ray Photoelectron spectroscopy (XPS) were also done. For electrochemical analysis these materials were applied on the 2.25 cm2 carbon cloth as active material (working electrode) by various electrochemical techniques in 1 M H2SO4 electrolyte. The Co NPs/Ti3C2Tx electrode had a maximum gravimetric capacity of 52 mAh g-1, specific capacitance of 580 mF cm-2 and 240 F g-1 at the current density of 1 mA cm-2. Figure 1

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.