Polymer Binder Research Articles

Effect of electrophysical nanopulse processing of cured polymeric binders

The results of an experimental study of the effect of electrophysical treatment of cured synthetic thermosetting resins on strength and water absorption are presented. The positive effect of increasing the strength and reducing the water absorption capacity of the cured samples of the studied resins after their irradiation with nanosecond electromagnetic pulses has been experimentally proven. The rational mode of irradiation of cured resins with nanosecond electromagnetic pulses has been established, during the implementation of which, for all the studied resins, a maximum increase in strength and a decrease in the water absorption index are observed.

Waterborne polymers and coatings from bio-based butenolides.

In the quest for sustainable paints and coatings, bio-based resources for the polymeric binder constituents are key. Recently, we introduced poly-butenolides as bio-based acrylate replacement for solventborne and 100% solids (UV-curing) coatings. Here, we report the first step towards aqueous poly-butenolide dispersions, enabling the use of this novel binder technology platform in waterborne coatings.

Tribological Properties of a Friction Composition of MetalCeramic Powders and Carbon-Containing Additives on a Polymer Binder Material

Tribological Properties of a Friction Composition of MetalCeramic Powders and Carbon-Containing Additives on a Polymer Binder Material

Achievements, challenges, and perspectives in the design of polymer binders for advanced lithium-ion batteries

The design of binders for lithium-ion batteries is highlighted, with an emphasis on key parameters affecting device performance and failure mechanisms. These issues are discussed in detail using the example of a silicon anode and a sulfur cathode.

Влияние длительного естественного старения теплоизоляционных минераловатных материалов на физико-химические и термические превращения

Purpose. The article studies physico-chemical and thermal transformations of mineral wool thermal insulation of natural ageing. The subject of the study is thermal insulation materials of natural ageing, and the object of the study is their physicochemical and thermal characteristics. The aim of the work is to establish physicochemical and thermal transformations of mineral thermal insulation of natural ageing. The research is aimed at identifying features of physico-chemical and thermal transformations of thermal insulation based on mineral fibers and organic binders in the ageing process. Methods. A set of precision physicochemical methods such as X-ray phase analysis (XRF), infrared spectroscopy and thermal analysis methods (TG, DTG, DSC) was used. Findings. The results of studying mineral thermal insulation (service life of 60 years) revealed characteristic changes in the structure of the material. The XRF method established that the ageing process of mineral wool materials is caused by occurring microdefects and disruption of material fibers structure organization. Changes in thermal insulation phase state have thermal fluctuation of kinetic nature of material mechanical destruction. The IR spectroscopy method identified changes in the areas of characteristic absorption bands: 2 800–2 200, 2 000–1 600 and 1 295–1 005 cm–1 caused by chemical destruction of organic binder in mineral thermal insulation. The nature of thermal transformations of the material was established, a tendency towards a decrease in the threshold temperatures for mass loss start due to destructing polymer binder was revealed. It is noted that natural ageing may result in loss of fire resistance of thermal insulation systems, as well as in intensificating smoldering combustion of thermal insulation. Research application field. The results are of interest to builders, designers, fire safety engineers and can be used in regulatory and technical as well as in reference literature on fire safety. Conclusions. During the ageing process irreversible physical and chemical changes occur in the structure of thermal insulation, leading to loss of thermal stability of the material and to a possible increase in the intensity of latent smoldering combustion. Technical obsolescence of the material leads to decreasing fire resistance limits of various thermal insulation systems due to loss of thermal insulation capacity and integrity.

Surface characteristics of phenolic resin coatings

Phenolic resins are commonly used as polymer binders for metal, paper and mineral wool substrates. For such applications, mechanical, adhesive and thermal properties are considered most important, and the effect of synthesis and structural parameters on such end-use characteristics are well-documented. However, surface characteristics of cured phenolic resins can be equally relevant and are often overlooked. Widely used resins are phenol-urea-formaldehyde (PUF) and phenol-formaldehyde (PF). It is believed that the inherent chemistry and curing procedure of these resins result in coatings with distinct surface properties and wettability. To gain more insight into surface characteristics such as morphology, chemical composition and wettability of cured PUF and PF resins, different binder formulations were applied on glass substrates and subsequently characterised by Scanning Electron Microscopy (SEM), Contact Angle Goniometry (CAG) and X-Ray Photoelectron Spectroscopy (XPS). The effect of catalyst, chemical composition and curing conditions on surface characteristics of various PUF and PF coatings were investigated. The curing temperature was found to have a strong influence on surface properties; curing at 200 °C yields a surface with varying degrees of oxidation, differences in linkages between phenolic and urea species, and a lower overall nitrogen content in case of urea-containing coatings, resulting in stronger fluctuations in water-wettability compared to surfaces hardened at lower temperatures.

Development of an effective technology for producing composite wood-plastic board materials for construction and furniture purposes

This article presents the results of research in the development of an effective technology for obtaining composite wood-plastic board materials for construction and furniture purposes based on fillers from cotton stalks, which are agricultural waste, and polymer binders based on modified urea-formaldehyde and gossypol resins, epichlorohydrin, benzyl chloride, and polyvinyl chloride. The study revealed a correlation between the ultimate bending strength, tensile strength and water absorption with the parameters of pressing polymer-fillers of the mass. At the same time, to obtain composite wood-plastic board materials, it is recommended to use a urea-formaldehyde resin modified with reactive structuring additives as a binder. It has been established that the optimal technological mode for pressing the mass of polymer fillers and cotton stalks is: specific pressure 35 kg/m², pressing temperature 168-170°C, heating duration 7-10 minutes. Key words: technology, composition, modified urea-formaldehyde resin, cotton stem filler, wood-plastic board, specific pressure, pressing temperature, heating duration, water absorption, tensile strength.

Water-soluble densely functionalized poly(hydroxycarbonylmethylene) binder for higher-performance hard carbon anode-based sodium-ion batteries

A high-density carboxylic acid containing water-soluble polymer binder, poly(hydroxycarbonylmethylene), enhances the specific capacity, rate capability and initial coulombic efficiency of hard carbon electrode in sodium-ion batteries.

Meta-kinks are key to binder performance of poly(arylene piperidinium) ionomers for alkaline membrane water electrolysis using non-noble metal catalysts

Tailored binder polymers enable high current densities for anion-exchange water electrolysis (AEMWE) for green hydrogen production without the necessity of noble metal catalysts.

Self‐Supported Earth‐Abundant Carbon‐Based Substrates in Electrocatalysis Landscape: Unleashing the Potentials Toward Paving the Way for Water Splitting and Alcohol Oxidation

AbstractIn the vast realm of scientific inquiry, the pursuit of hydrogen fuel production through electrochemical water splitting offers a promising gateway to green energy generation, alleviating the challenges posed by resource scarcity. However, conventional water splitting encounters hurdles like low efficiency and the sluggish oxygen evolution reaction (OER), which prompt searchers to seek for alternative oxidation process. Significant strides are made in conventional electrocatalytic research employing polymeric binders, resulting in commendable catalytic activity and minimal electron migration resistance. Yet, a pivotal breakthrough in this rapidly evolving field lies in the innovative conception of carbon‐based self‐supported electrocatalysts, heralding a promising trajectory ahead. This review delves into the essential electro‐activity parameters to establish the property‐activity nexus, emphasizing the benefits of self‐supported carbon‐based electrodes. Noteworthy advancements are demonstrated in electrochemical hydrogen evolution reaction (HER), OER, overall water splitting (OWS), and bifunctional HER and alcohol oxidation reaction (AOR), driven by a diverse range of self‐supported electrocatalysts. These include structure‐dependent materials such as metal oxides, hydroxides/oxyhydroxides, phosphides, sulfides, selenides, nitrides, and carbides, each meticulously tailored with nuanced modifications that shape their distinctive attributes. This field also acknowledges its challenges and opportunities, providing guidance for potential research directions and inspiring interdisciplinary collaboration among scientists.

Performance and Characterization of Ceramic Membrane by Phase Inversion-Extrusion Process with Polymer Binder Mixing

Performance and Characterization of Ceramic Membrane by Phase Inversion-Extrusion Process with Polymer Binder Mixing

Development of Moisture Absorbent Ceramic-Coated Separators for Advanced Lithium-Ion Batteries

In the present human life, various electric devices and machines are worked by lithium-ion batteries (LIBs). The batteries have still remained challenges such as, the low cycling stability due to side reactions during charge-discharge cycling and the weak thermal stability at high temperatures. Accordingly, research on improving resistance to high temperatures and impregnability by coating ceramic particles and polymer binders on the surface of the separator is being conducted. The ceramic coating separator is manufactured by connecting small-sized inorganic particles to each other using a small amount of binder. The inorganic particles have high hydrophilicity and high specific surface area, so the ceramic separator has excellent wettability to the electrolyte. As a ceramic coating, alumina is currently commercialized, and a slurry is prepared by mixing a binder, etc., and then coated on a separator and then dried. LG Energy Solutions has commercialized a ceramic composite separator called SRS (Safety-reinforcing separator) and is applying it to batteries. By introducing a ceramic layer on the surface of a polyolefin-based separator, the heat resistance and mechanical strength of the separator have been greatly improved, and it has been widely used in high-capacity and large-sized batteries. when the temperature of the LIBs rises and the separator shrinks or ruptures, a large amount of lithium ions may move, making control difficult and creating a risk of explosion. Therefore, shutdown occurs, but a separator with good shape retention at high temperature is required. Accordingly, research on improving resistance to high temperatures by coating ceramic particles and a polymer binder on the surface of the separator is being conducted. In this work, Ceramic-coated separator membrane film was fabricated using aluminum fluoride (AlF3) materials for a powerful moisture (H2O) scavenger. Accordingly, research on improving high temperature resistance and impregnation property by coating ceramic particles and a polymer binder on the surface of the separator is in progress. First of all, a-AlF₃ nanorods with an average length of 1.882 μm and a diameter of 320 nm were synthesized under low supersaturation conditions. Then, PVdF-HFP [Poly(vinylidene fluoride-co-hexafluoropropylene)]-acetone solution was mixed and coated on a polypropylene membrane. The AlF₃-coated separator exhibited thermal shrinkage of 4%, 8%, and 18% at 130, 140, and 150°C, respectively, confirming that thermal stability was improved. In addition, as a result of the impregnation test, it was confirmed that the impregnation property of the coated separator was improved compared to the existing polypropylene separator. In addition, it was confirmed that the full cell manufactured using the a-AlF₃-coated membrane film has improved cycle stability and high-speed, high-capacity compared to the full cell manufactured using the existing non-coated separator.

(Invited) Design of Specific Polymer Binders for Stabilization of Si Based Anode in Lib

In recent years, intense efforts have been focused on stabilization of silicon-based anode in Li ion secondary batteries due to their remarkably high theoretical capacity. At the same time, strategy has not yet been established on how to stabilize the silicon based anode sufficiently during long cycles so that it will be feasible for practical use. In this talk, several different approaches on stabilization of silicon-based anode will be introduced both in terms of polymer binders design and active materials design. Our group synthesized several self-healing polymer binder and polymer coating material which are efficient for the use in silicon-based anode. Poly(borosiloxane) (PBS)1 was prepared by dehydrocoupling polymerization between mesitylborane and diphenylsilanediol in the presence of transition metal catalyst. PBS was found to show self-healing property at 45oC when coated onto Si electrode. When PBS coated Si electrode was employed for anodic half cell (Si/EC:DEC (1/1=v/v)/Li), it showed much improved durability when compared with PVDF coated Si based cell or bare Si based cell. We also reported a design of BIAN (bis-imino-acenaphthene) based conjugated polymer (P-BIAN) /Poly(acrylic acid) (PAA) composite binder for Si based anode2,3. Due to combination of n-type imine-based conjugated polymer (H-bonding acceptor) and PAA (H-bonding donor), synergistic effect in stabilization of Si/C composite anode was observed due to both of desirable electronic structure of P-BIAN and H-bonding based self-healing properties. In this system, anodic half cell delivered specific discharging capacity of above 2000 mAhg-1 for 600 cycles. As alternative approaches, we are also working on preparation of specific Si based anodic active materials which showed extremely high durability. b-SiC/N-doped carbon4 was found to show excellent durability even in the presence of conventional binder materials due to restricted volumetric changes of b-SiC during lithiation/delithiation. We also report coating of mechanically highly robust silicon oxycarbide on micro silicon5, which was also found to be quite effective.References1) Patnaik, S. G.; Jayakumar, T. P.; Sawamura, Y. Matsumi, N. ACS Appl. Ener. Mater. 2021, 4, 2241.2) Gupta, A.; Badam, R.; Matsumi, N. ACS Appl. Ener. Mater. 2022, 5, 7977.3) Gupta, A.; Badam, R.; Nag, A.; Kaneko, T.; Matsumi, N. ACS Appl. Ener. Mater. 2021, 4, 22314) Nandan, R.; Takamori, N.; Higashimine, K.; Badam, R.; Matsumi, N. J. Mater. Chem. A. 2022, 10, 5230.5) Nandan, R.; Takamori, N.; Higashimine, K.; Badam, R.; Matsumi, N. J. Mater. Chem. A. 2022, 10, 15960.

(Invited) Impact of Binder Selection in Advanced Lithium Battery Electrode Fabrication and Performance

Polymer based binder plays an important role in electrode structures for varies energy storage systems such as battery and capacitor. In conventional wet coating process for battery electrode fabrication process, the polymer binders are mixed with the active material and conductive additives to form the slurry for the coating. The binders provide both physical and chemical supporting to the overall electrode structure, in addition to the basic “gluing” function. In recent years, a lot of aqueous soluble polymers were introduced in lithium-ion battery study working as alternative of traditional PVDF binder. The application of aqueous based polymer binder covers graphite, silicon, metal oxide, and even sulfur electrode fabrication. In this talk we will present some of our recent study on selected polymer binders in certain chemistry, such as Li-S system. We will reveal the difference in both physical and chemical properties of the selected binders, as well as the impact on the overall electrochemical performance. We will also discuss the binder selection and challenges from manufacturing point of view.

Covalently Joined Electrode Architectures for Extreme Fast Charging Li-Ion Batteries

Li-ion batteries are the backbone of all electric vehicles (EVs) in production today [1]. However, they compete poorly against the few-minute refueling time of fossil fuel powered vehicles [2, 3]. To successfully replace fossil fuel powered vehicles, the EV batteries must support charging rates under the 15-minute mark as determined by the eXtreme Fast Charging (XFC) standard defined by the U.S. Department of Energy [4]. When subjected to XFC charging rates, well-known problems of lithium plating and delamination plague graphite anodes due to local potential gradients and binder degradation respectively [5].Our work replaces the traditional polymer binder with conductive titanium carbide interconnects that covalently join graphite particles as well as bond them to the current collector [6]. This new architecture demonstrates ~400% increase in electrical conductivity compared to traditional architectures with polymer binders while maintaining interparticle integrity and improving adhesion. The adhesion and mechanical properties are provided by conductive chemical bonds mitigating delamination as these novel bonds suffer less mechanical and chemical degradation under high current rates than adhesion provided by polymer binders. The improved conductivity was also utilized to form a solid electrolyte interphase (SEI) at rates up to 4C reducing the ionic impedance of the SEI interface significantly [7]. The improved graphite electrodes can sustain 15-minute charge maintaining 80% of the specific capacity of the graphite particles for 800 cycles at commercially relevant loadings. Our studies introduce an effective strategy to engineer Li-ion battery electrode architectures that simultaneously improve electrical and ionic conductivity mitigating lithium plating and delamination under XFC charging rate needed for the mass adoption of EVs. Habib, A.A., S. Motakabber, and M.I. Ibrahimy. A comparative study of electrochemical battery for electric vehicles applications. in 2019 IEEE International Conference on Power, Electrical, and Electronics and Industrial Applications (PEEIACON). 2019. IEEE.Balali, Y. and S. Stegen, Review of energy storage systems for vehicles based on technology, environmental impacts, and costs. Renewable and Sustainable Energy Reviews, 2021. 135: p. 110185.Andwari, A.M., et al., A review of Battery Electric Vehicle technology and readiness levels. Renewable and Sustainable Energy Reviews, 2017. 78: p. 414-430.Dufek, E.J., et al., Developing extreme fast charge battery protocols–A review spanning materials to systems. Journal of Power Sources, 2022: p. 231129.Ahmed, S., et al., Enabling fast charging–A battery technology gap assessment. Journal of Power Sources, 2017. 367: p. 250-262.Rangom, Y., Covalently Joined Carbonaceous and Mettalloid Powders by Carbide-Based Interconnects and Method of Fabrication for High-Performance Electrodes. 2021: United States preliminary patent #63/248,293.Rangom, Y., T.T. Duignan, and X. Zhao, Lithium-ion transport behavior in thin-film graphite electrodes with SEI layers formed at different current densities. ACS Applied Materials & Interfaces, 2021. 13(36): p. 42662-42669. Figure 1

(Invited) All-Solid-State Na- and K-Ion Batteries with Dry Polymer Electrolytes

The development of sodium-ion and potassium-ion batteries has gained increasing attention as a sustainable and cost-effective alternative to lithium-ion batteries, due to the abundance of their constituent elements.[1]-[3] All-solid-state batteries offer high safety advantages in high-temperature conditions, as their solid composition reduces the risk of leakage or ignition of the organic electrolyte. As large-scale and stationary batteries for energy storage applications require safety and durability in wide-temperature operations, all-solid-state sodium-ion and potassium-ion batteries can provide a potential solution.This study presents the fabrication of all-solid-state sodium batteries, using dry polymer electrolytes, optimized for stable operation at 60 °C.[4] A composite electrode with uniformly dispersed conductive carbon and binder polymer is essential to achieve a stable charge-discharge reaction in all-solid-state cell, due to the absence of the liquid electrolyte penetrated in the electrode pores. The use of a polymer electrolyte as a binder polymer provides an effective ionic conduction path inside the electrode, which allows stable charge-discharge reaction even at the thick composite electrodes. The fabricated all-solid-state Na // P2-Na2/3[Ni1/3Mn2/3]O2 cell exhibits superior cycle performance at 60 °C, compared to the liquid electrolyte. Furthermore, coating P2-Na2/3[Ni1/3Mn2/3]O2 with Al-oxide enhances the capacity retention of the P2-Na2/3[Ni1/3Mn2/3]O2 // hard carbon full cell, with a mean discharge voltage of 3.11 V and energy density of 148 Wh (kg of active material)−1. To the best of our knowledge, this is the highest value ever reported for full-cell operation of an all-solid-state sodium-ion battery using a dry-polymer electrolyte.The study also reports the fabrication of all-solid-state potassium batteries, where the effects of K metal pretreatment on the K metal/solid polymer electrolyte interface were investigated.[5] The use of K metal chunk, pretreated with the electrolytes containing potassium bis(fluorosulfonyl)amide (KFSA), effectively suppressed polarization and interfacial resistance during continuous K metal stripping-deposition reactions in the cross-linked polymer electrolyte, poly[ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether-co-allyl glycidyl ether] (P(EO/MEEGE/AGE)). The addition of 1,3,2-dioxathiolane 2,2-dioxide (DTD) to the pretreatment solution further decreased polarization and interfacial resistance, due to the formation of a stable passivation layer on K metal by FSA− ions and DTD. The efficient operation of the potassium iron hexacyanoferrate positive electrode and graphite negative electrode in P(EO/MEEGE/AGE), with the K metal counter electrode, was achieved by effectively suppressing interfacial resistance through pretreatment. Stable K metal counter electrode for all-solid-state potassium cell was also beneficial to design full cell of all-solid-state potassium-ion cell, enabling us to fabricate the first 3 V-class all-solid-state K-ion battery operated at room temperature.

Initial Degradation Issues in AEMWE and the Importance of Catalyst/Ionomer Binding

With the recent development of highly alkaline stable anion exchange membranes (AEMs) and ionomers (AEIs), anion exchange membrane water electrolyzer (AEMWE) has garnered attention due to its ability to achieve high hydrogen production rate at a low cost. The performance of AEMWE is determined by the anode catalyst layer, which can be made up of either a mixture of metal nanoparticles and polymer binders or a single metal. Although the integral metal has high mechanical properties, its performance is limited due to low electrochemical surface area and difficulties in mixing with binders, which makes it unsuitable for use in pure water. Catalyst layers made up of a combination of metal nanoparticles and polymeric binders can achieve high performance with a large surface area, but they often have low durability due to detachment of the anode catalyst layer from the porous transport layer substrate during water electrolysis. To prevent this, the anode catalyst layer must have high physical stiffness and it can be achieved by the strong bonding between the metal nanoparticles and the ionomer binder. This presentation investigates the phenomenon of initial performance degradation in AEMWE with an anode catalyst layer composed of metal nanoparticles, highlights the significance of the physical stiffness of the anode catalyst layer, and proposes that the issue can be resolved by introducing a polymer binder with high adhesion between the metal nanoparticles and the ionomer binder.

PFAS-Free Carbon Electrodes for Efficient Micropollutants Removal through Heterogeneous Electro-Fenton: From Material Synthesis to Module Design

Emerging micropollutants (MPs) in water bodies such as pharmaceuticals, pesticides, personal care products, and per-and poly-fluoroalkyl substances (PFAS) have posed environmental, ecological, and anthropological issues since MPs are too persistent to be degraded by conventional biological treatment. On the other hand, electrochemical advanced oxidation processes (EAOPs) have proved themselves as efficient and robust techniques to unselectively degrade MPs by forming OH radicals (•OH). Among EAOPs, electro-Fenton, or more specifically heterogeneous electro-Fenton (HEF), suggests an eco-friendly and energy-efficient treatment technique with a wide pH range for removing persistent MPs. In HEF, hydrogen peroxide (H2O2) is electrochemically produced on the cathode surface, which can react with immobilized, adjacent Fe catalysts for •OH generation. Yet, one challenge for HEF is that most of the studies have primarily focused on synthesizing Fe-containing carbons as a catalyst that suffers from several delicate preparation steps, which are time-, chemical-, and energy-consuming and lack reusability over consecutive runs [1].Additionally, these catalysts are usually powders, entailing adding polymeric binders for the immobilization of the catalyst layer on electrodes. The presence of polymeric binders, e.g., polytetrafluoroethylene (PTFE)—as PFAS-containing compounds on the electrode surface—enhances the risk of PFAS contamination during the HEF process due to mechanical wear-off or degradation under the harsh oxidative condition caused by the formation of unselective •OH. Therefore, developing PFAS-free carbon electrodes for the HEF process offering facile fabrication and good reusability with a scaling-up perspective is imperative to enable decentralized solutions for MPs removal, especially highly recalcitrant PFAS. In this work, freestanding carbons made of bio-based precursors, chitosan and sucrose, serve as electrodes for the HEF process. Chitosan is the backbone for the self-standing feature and a nitrogen-rich biopolymer, while sucrose serves as a carbon-rich compound. The mixture of chitosan and sucrose undergoes silica- and ice-templating to make a hierarchically porous carbon [2]. Bio-based carbons illustrated their capability for oxygen reduction reactions, particularly the electro-generation H2O2 [3]. As-synthesized carbons proved to remove carbamazepine and sulfamethoxazole as two persistent MPs at pH 3 and pH 7 [3]. Moreover, a novel flow-through electrolysis module equipped with as-synthesized carbons has been designed and operated to remove 20 mg/L CBZ solution at a current density of 20 mA/cm2. This module design demonstrates the ease of scaleup for a decentralized water/wastewater treatment unit to remove highly recalcitrant MPs.

(Invited) Autonomous Self-Healable Silicon Anode for Next Generation Lithium-Ion Batteries

Self-healing is a measure of material's ability to repair damage. Physical and chemical processes have been used to obtain self-healing polymers for various applications. Different approaches are involved for these systems, such as shape-memory effects, covalent-bond reform, heterogeneous systems, diffusion and flow, and the dynamics of supramolecular chemistry. Different approaches are used to achieve self-healing polymers, in particular, the role of the healing system in chemistry is highlighted, which enables thermal transients, damage repairing and reconnection. Moreover, self-healing systems and their energy storage applications are currently getting great importance. Inspired by the dynamic network structure of animal dermis, in which collagen fibril (rigid and strong) and elastin fibril (soft and elastic) crosslink through supramolecular interactions to form a sturdy and flexible material we hypothesized that the combination of a rigid conductive polymer with a soft hydrophilic polymer through proper supramolecular interactions would yield a strong and robust polymer binder.According to the literature, the external stimulus such as heat, light, pH and redox initiate the healing process. This process is known as non-autonomous self-healing when some additional external stimulus is needed. Considering the battery chemistry, it is the most functional method to choose self-healing structures and batteries with the help of hydrogen bonds in order to make the self-healing process occurs autonomously. In the literature, polymerized β-cyclodextrin (β-CD) has been used as an advanced binder for Si-nanoparticle anodes, and cracks in the electrode can be avoided with its reversible properties through supramolecular cyclodextrin or hydrogen bonding compounds[1]. Dynamic bonds such as hydrogen bonds between composites positively affect the durability of the Si anode performance. For example, the Si anode was coated by the researchers with hydrogen bond-oriented polymer binder layers based on polyimide polymer such as Upy, resulting in electrochemical performance ten times longer than conventional silicon anodes[2].Horizon projects such as BAT4EVER and HIDDEN under Battery 2030+ initiative have been investigate the integration and optimization of self-healing polymers in Li-ion battery [3]. In the scope of the BAT4EVER project, supramolecular coupling of polyaniline and polyvinyl alcohol via dynamic boronate bond yields polyaniline-polyvinyl alcohol hydrogel with outstanding tensile strength and electrochemical performance. The self-healing chemistry in the Si anode prevents unbalanced volumetric changes and cracks on the electrode surface. Thus, electrochemical performance losses are decreased. The self-healing functionalized components of lithium-ion batteries, which focus on improving and optimizing properties such as high energy density, high voltage, long life, and cycle stability, are of great importance for next-generation batteries.References Jeong, Y.K., Kwon, T.W., Lee, I., Kim, T.S., Coskun, A., Choi, J.W.: Hyperbranched β-cyclodextrin polymer as an effective multidimensional binder for silicon anodes in lithium rechargeable batteries. Nano Lett. 14, 864–870 (2014). https://doi.org/10.1021/NL404237J/SUPPL_FILE/NL404237J_SI_001.PDFYang, J., Zhang, L., Zhang, T., Wang, X., Gao, Y., Fang, Q.: Self-healing strategy for Si nanoparticles towards practical application as anode materials for Li-ion batteries. Electrochem commun. 87, 22–26 (2018). https://doi.org/10.1016/J.ELECOM.2017.12.023https://battery2030.eu/ This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 957225 (BAT4EVER).

(Invited) Challanges with Novel Binders for LiNi0.5Mn1.5O4 li-Ion Battery Electrodes

In the search for high-energy density Li-ion battery electrode materials which are also comparatively sustainanble, LiNi0.5Mn1.5O4 (LNMO) is often targeted as a promising next-generation alternative. While the capacity of LNMO is limited, it has a high operating voltage around 4.7 V vs. Li+/Li, and the spinel structure of the materials renders useful power capacilities. Moreover, it is a cobalt-free cathode. However, fabricating functional electrodes have shown problematic due to inherent instabilities at both bulk and surfaces, where especially operation at elevated temperatures has shown to cause capacity degradation. Problems comprise structural changes, loss of oxygen, and Mn dissolution, often interconnected with each other. One strategy to improve stabilization would be through coatings of the LNMO particles, either inorganic or organic.The polymer binder used for battery processing is inherently an organic coating layer, since it wraps around the particles of the electrodes. Thereby, binders has been shown to being able to add functionalities to electrode materials, e.g. to improve electronic conductivity, add storage capacity or mitigate side-reactions. The binder is at interplay with the reactions causing interphase layer formation. Thereby, changing or taioring the binder can cause direct improvements in cell performance.Poly(vinylidene difluoride) (PVdF) and its many derviates is since long time the standard for Li-ion battery electrodes, despite not being particular sustainable and being dependent on toxic solvents such as N-methyl-2-pyrrolidone (NMP). LNMO is, in this context, no exception. Nevertheless, while PVdF is chemically intert, it provides little other capabilities to the battery electrodes, and other binder systems could improve in this context: either through electochemica performance or through being more sustainable.Here, two other binder systems for LNMO are discussed: polyacrylonitrile (PAN) and polyacrylic acid (PAA). Polynitriles are often promoted as being comparatively stable at higher potentials, while also being ionically conductive, and should therefore in principle add functionalities into the resulting electrodes. PAA, on the other hand, has shown good adhesion and adherence to oxide surfaces, and can thereby form more robust interfacial layers on the cathode. We show here, however, that challenges remain for these alternative binder systems, not least due to the high operating potential of LNMO electrodes which cause side-reactions of both types of alternative binders. These side-reactions are their products are analyzed through a range of methods, e.g. photoelectron spectroscopy, electron microscopy and electroanalytical techniques, thereby providing guidance to the development of novel binders for high-voltage electrodes.