Binder For Anode Research Articles

Cross-linking γ-Polyglutamic Acid as a Multifunctional Binder for High-Performance SiOx Anode in Lithium-Ion Batteries.

SiOx is a highly promising anode material for realizing high-capacity lithium-ion batteries owing to its high theoretical capacity. However, the large volume change during cycling limits its practical application. The development of a binder has been demonstrated as one of the most economical and efficient strategies for enhancing the SiOx anode's electrochemical performance. In this work, a multifunctional binder (T-PGA) is fabricated by cross-linking γ-polyglutamic acid (PGA) and tannic acid (TA) for SiOx anodes. The introduction of TA into PGA helps to buffer the volume changes of the SiOx anodes, facilitate diffusion of Li+, and construct stable SEI layers. Benefiting from this proposed binder, the SiOx anode maintains a reversible capacity of 973.0 mAh g-1 after 500 cycles at 500 mA g-1 and the full cell, pairing with LiNi0.5Co0.2Mn0.3O2 cathode, delivers a reversible capacity of 133 mA h g-1 (73.2% retention) after 100 cycles. This study offers valuable insights into advanced binders that are used in high-performance Li-ion batteries.

Binder‐induced inorganic‐rich solid electrolyte interphase and physicochemical dual cross‐linked network for high‐performance SiOx anode

AbstractSilicon oxide (SiOx) is heralded as the forefront anode material for high‐energy density lithium‐ion batteries, owing to its exceptional specific capacity. Nevertheless, the traditional combination of polyacrylic acid binder and acetylene black conductive carbon continues to struggle with the immense stress induced by the repetitive volume expansion and contraction processes. Here we report a high ionic conductivity, sulfonyl fluoro‐containing binder for SiOx anode via free radical copolymerization reaction between perfluoro (4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride and acrylic acid. The electrode fabrication process incorporated amino‐functionalized carbon nanotubes (CNT‐NH2) as the conductive agent. A three‐dimensional conductive network structure is constructed through physical and chemical double cross‐linking interactions between the ‐COOH and ‐SO2F functional groups of PAF0.1 binder, the ‐NH2 groups of CNT‐NH2, and the ‐OH groups on the surface of SiOx, including hydrogen bonds and covalent bonds. In addition, the binder induces the formation of a solid electrolyte interphase (SEI) rich in inorganic components such as Li2O, Li2SO3, Li2CO3, and LiF. Benefiting from the synergistic effects of the physically and chemically double cross‐linked three‐dimensional conductive network constructed by the PAF0.1 binder and CNT‐NH2, coupled with the rich‐inorganic SEI, the SiOx anode delivers exceptional rate performance, cycle stability, and lithium‐ion diffusion dynamics.

Electrode Binder Design on Silicon‐Based Anode for Next‐Generation Lithium‐Ion Batteries

AbstractAs an important part of the electrode material of lithium‐ion batteries, the binder significantly affects the forming strength of the solid electrolyte interface (SEI), and also determines the mechanical properties and cycling stability. In the silicon anode, binder have greater effect in the chemical and electrochemical stability because of the volume of the silicon anode changes by more than 300 %. Thus, the development of functional new binders with enhanced properties is one of the keys to mitigating the instability of silicon anodes. This concept first briefly introduces the advantages and disadvantages of conventional electrode binders, then the current research progress of silicon anode binders is briefly summarized based on the different types of interaction forces of binders. Finally, we conclude the properties indicators of silicon anode binders with superior performance in batteries, and comment our previous work in detail.

Cross-Linkable Binders for Si Anodes in High-Energy-Density Lithium-Ion Batteries.

Although silicon (Si) has a high theoretical capacity, the large volume expansion during lithiation has greatly hindered its application in high-energy-density lithium-ion batteries (LIBs). Among the strategies for improving the performance of Si anode, the role of binders should not be underestimated. Here, a novel strategy for designing a cross-linkable binder for Si anode has been proposed. The binder with hydroxyl and nitrile groups can be in situ covalently cross-linked through the amide group in the batteries. The cross-linked binder (c-POAH) shows high elasticity and strong adhesion to Si particles and the current collector. Si||Li half coin cells using the c-POAH binder have excellent cycle performance and the capacity retention ratio is 67.1% after 100 cycles at 0.2 C. Scanning electronic microscopy images show that the c-POAH binder can contribute to suppressing the pulverization of the Si anode. Moreover, the investigation with X-ray photoelectronic spectrum demonstrates that the decomposition of the liquid electrolyte on Si anode has been mitigated and the c-POAH binder can promote the formation of a more stable SEI film. Our strategy of endowing the binder with good elasticity through in situ cross-linking has opened up a new route for developing binders, which will definitely promote the application of Si anodes in high-energy-density LIBs.

The performance of microbial fuel cell with sodium alginate and super activated carbon composite gel modified anode

Microbial fuel cells (MFCs) have the functions of wastewater treatment and power generation. The incorporation of modified anodes enhances the sustainable power generation performance of MFCs. In this study, to evaluate the feasibility of sodium alginate (SA) as a biocompatible binder, hydrogel mixed with super activated carbon (SAC) and SA was modified the carbon cloth anode of MFC. The results showed that the maximum output voltage in the SAC/SA hydrogel modified anode MFC was 0.028 V, which was increased by 115%, compared with the blank carbon cloth anode. The internal resistance of MFC was 9429 Ω, which was 18% lower than that of control (11560 Ω). The maximum power density was 6.14 mW/m2, which was increased by 365% compared to the control. After modification of SAC/SA hydrogel, the chemical oxygen demand (COD) removal efficiency reached to 56.36% and was 12.72% higher than the control. Coulombic efficiency with modified anode MFC reached 17.65%, which was increased by 104%, compared with the control. Our findings demonstrate the feasibility of utilizing SA as a biocompatible binder for anode modification, thereby imparting sustainable and enhanced power generation performance to MFCs. This study presented a new selectivity for harnessing algal bioresources and improving anode binders in future MFC applications.

Design Principle and Development Trends of Silicon-Based Anode Binders for Lithium-ion Batteries: A Mini Review

Abstract: Silicon (Si), recognized as a promising alternative material for the anodes of lithium-ion batteries, boasts a high theoretical specific capacity and abundant natural availability. During the preparation of silicon-based anodes, binders play a pivotal role in ensuring the cohesion of silicon particles, conductive agents, and current collectors. The structure and performance of these binders are critical for the mechanical stability, electrical conductivity, and stress dissipation capacity of the anodes. This review initially outlines the structural characteristics of various binders, including linear, branched, and three-dimensional cross-linked types. It then delves into the relationship between the structure and properties of these binders in the context of their application in high-performance lithium-ion batteries, focusing on their mechanical properties, electrical conductivity, and self-healing capabilities. Particular attention is given to the design strategies for binders that facilitate stress dissipation, with an emphasis on integrating multifunctional polymer binders renowned for their superior conductive and self-healing features. Such binders contribute to the formation of a robust three-dimensional network structure via multiple bonding mechanisms, including chemical, non-covalent, and coordination interactions. This configuration significantly enhances the adhesion between silicon particles, thereby facilitating the efficient dissipation of stress, which is a key aspect for ensuring the long-term cycling stability of lithium-ion batteries. Lastly, the paper explores future development directions for silicon anode binders, advocating for a thorough investigation into the synergy of diverse structural and functional combinations, with the aim of advancing the performance and practical application of silicon-based lithium-ion batteries.

High performance carboxymethyl cellulose- polyethylene oxide polymer binder for black phosphorus anode in lithium-ion batteries

Black phosphorus (BP) is regarded as a promising anode material due to its high theoretical specific capacity and fast charging safety. However, the problems of huge volume expansion and moderate electrical conductivity may restrict its performance. In this work, we present a novel 3D network binary polymer binder synthesized from carboxymethyl cellulose (CMC) and polyethylene oxide (PEO) for adapt to lithium-ion batteries of BP and graphite (G) composite anode (BP-G). There are the following characteristics of the binder: CMC and PEO are crosslinked through intermolecular forces; while CMC and PEO are connected to BP through strong intermolecular forces, respectively; BP and graphite are connected through PC and POC bonds to form composite anode. So as to form a sturdy structure and effectively accommodate the volume expansion of BP during charging-discharging processes, while avoiding loss of electrical contact between electrode components. Accordingly, the lithium-ion battery shown an excellent electrochemical performance, such as a high initial discharge capacity of 1602 mA h g−1 at 0.5 A/g.

Integrating with a tough framework and efficient self-healing behavior based on a flexible polymer skeleton for Si anode binders in lithium-ion cells

As a prospective and efficient strategy to address the volume expansion of the Si nanoparticles, the binder plays an increasingly significant role in the Si anode of lithium-ion batteries. Based on the inspiration of natural physics and cross-linked networks, a functional (named polyacrylic acid-citric acid-polyethyleneimine) binder that is similar to a flexible polymer skeleton integrated with a tough framework and efficient self-healing behavior is designed to achieve long cycling stability for Si anodes. The cross-linked network can be stabilized by the amide bonds, formed by polyethyleneimine (PEI) and polyacrylic acid (PAA). Based on this, citric acid (CA) can be added to form multiple hydrogen bonds, whose carboxyl groups can also establish a more reversible cross-linked network with Si particles. Then, PEI and CA molecules can connect with PAA to form a “rigid and flexible” structure. The expansion stress of Si nanoparticles is relieved by the protective buffer layer built by the addition of PEI and CA molecules. In addition, PAA, PEI, and CA work together to solve the problem that the action of CA and PAA alone cannot perform well under large currents. Hence, this water-based binder with a three-dimensional cross-linked network structure with self-healing ability has better performance during cycling: at a current density of 0.2C, it still has a capacity of 2017.4 mAh·g−1 after 200 cycles, with a capacity retention rate of 80.7 % (1745.3 mAh·g−1, 300 cycles, a capacity retention of 74.9 %).

A Lithium Polyacrylate-based High-performance Composite Binder for Graphite Anode

A Lithium Polyacrylate-based High-performance Composite Binder for Graphite Anode

Co-operation of hydrogen bonds and dynamic covalent bonds enables an energy-dissipative crosslinked binder for silicon-based anodes

An energy-dissipative and self-healed binder is achieved by combining multiple H-bonds and covalent bonds. Good electrochemical performances of Si and Si/C anodes are delivered, showing great advancement in the development of Si-based anode binders.

Solid-State Redox-Active Pseudocapacitor with Improved Performance at High Temperature

With the emergence of environmental issues such as global warming as well as our new demand for efficient energy storage systems (EES) that can power portable electronics; batteries and supercapacitors are gaining more attention in the latest literature. Batteries can provide high energy density and lower power densities (e.g. for LIB, 1kW.kg-1 vs. 150-200 Wh.kg-1), while supercapacitors are high power devices with low energy densities (e.g. for most commercial devices ⁓ 10 kW.kg-1 vs. 5-10 Wh.kg-1). In order to couple high energy and high power densities of both devices, pseudocapacitance was introduced in 1991 by Conway 1 using metal oxide. Pseudocapacitance is a fast and reversible surface faradaic process with performance similar to double layer capacitors but higher energy densities closer to that of batteries. Aside from metal oxides, conductive polymers also demonstrate pseudocapacitance. In this regards, the use of conductive polymers as nontoxic, abundant, low cost and sustainable organic material is on the rise. Nevertheless, the inherent issue related to instability of the conductive polymer especially at high degree of oxidation had restricted their application in EES. However, redox active polymers (RAPs) with non-conjugated backbone and redox active pendant group demonstrates improved performance and structural diversity with more distinct redox potentials. 2 Amongst them, quinone-containing polymers with their high theoretical capacities, facile kinetics and tunable redox potential are at the top of the list. Particularly, catechol, a bioinspired ortho-quinone based polymer has gain popularity following a work by Detrembleur et al. 3 However; the solubility of the organic materials in organic solvents hinders their application in EES. To this end, using solid-state electrolyte can help alleviate the issue. Nevertheless, solid-state design stimulate sluggish kinetics and reduce electrode/electrolyte interfacial area, a component required to achieve high pseudocapacitance. Consequently, nano-structuring the redox polymer can help improve the contact resistance as well as increasing the surface area. In addition, the nanoparticles structure will promote more distinct redox processes. 4 In this study, we demonstrate for the first time, a prototype pouch cell based on all-solid-state organic hybrid supercapacitor bearing catechol redox active moieties. Using emulsion polymerization, catechol based RAP nanoparticles of size ranging from 50 to 150 nm were synthesized 4 and together with activated carbon was used as working electrode. Block-co-polymers based solid electrolyte was employed as electrolyte as well as binder for both cathode and anode. Using this design, discharge capacities of ⁓ 10 and 60 mAh/g at room temperature and at 50 °C were obtained, respectively.

(Invited) Binder Investigation for Silicon Electrode of Lithium-Ion Batteries

Though the binder is not an active material and does not contribute capacity to lithium ion batteries (LIBs), it is an important ingredient for maintaining the integrity of the electrode, which helps to improve electrical contact between the active materials and conductive carbon black, improves the Li+ transport efficiency, reduces the internal resistance of Li-ion batteries and effectively depresses the crack formations and phase separation.Polyvinylidene fluoride (PVDF) is a polymer that is commonly used as a binder for both anode and cathode materials in LIBs. However, it is not suitable for Si electrode due to its poor binding capability and stability. Viewed as a next generation anode material, Si has been extensively studied due to its extremely high theoretical specific capacity of 3578 mAh/g (assuming Li15Si4 as intermediate product). However, silicon undergoes huge volume variations during repeated discharge and charge, which requires a strong binder to maintain the electrode mechanical integrity. Developing a high strength binder for silicon anodes has been considered as an efficient pathway to alleviate various capacity decay pathways.Polyacrylic acid (PAA) and its lithiated version (LiPAA), rich with carboxy function group, can provide stronger binding and are widely used as binder for Si electrode. In this work, we optimized Si electrode formulation by varying the binder composition. The optimized Si electrodes were electrochemically tested in both half cells and full cells. With improvement in electrochemical performance, cracks at the electrode level can still be observed for the cycled electrodes, which suggests that a stronger binder is required to mitigate volume expansion of Si electrodes and hold the particles together.We further studied the polyimide (PI) materials as binders for Si anodes in an attempt to achieve more stable cycling performance. In this work, we explore various PI crosslinking conditions and their effects on electrochemical performance. The optimized silicon electrode exhibits a higher tensile strength than that of conventional PAA binder. The strong adhesion of the PI binder suppresses the structural collapse of the Si negative electrode during lithiation/delithiation, enabling good capacity retention and stable cycle life.

High Performance Anode Binder

Binders are inactive but necessary component of the electrodes and without using a proper binder, the performance of LIBs would prematurely degrade. A well-designed binder allows to increase the electrode energy density by reducing the binder demand, as well as increasing the cycle-life by maintaining an adequate mechanical integrity and ionic mobility within the electrode.This poster will present a newly designed high-performance anode binder by Arkema. IncellionTM EL 1061 is a high purity WB binder, could overcome the limitations of traditional binders, and allows to maximizing the performance of conventional anodes –including graphite loading of > 97%, first cycle efficiency of > 93%, high C-rate capability of 2C/0.2C of > 96.5%, and capacity retention of > 92% after 500-cycles in 18650 cells- without a need to change the anode design. Moreover, double-sided anodes of > 35 mg/cm2 loadings were successfully fabricated using this high-performance binder and tested in 75 Ah high energy density pouch cells needed for demanding applications.

Dynamic hydrogen bond cross-linking binder with self-healing chemistry enables high-performance silicon anode in lithium-ion batteries

The structure instability and cycling decay of silicon (Si) anode triggered by stress buildup hinder its practical application to next-generation high-energy–density lithium-ion batteries (LIBs). Herein, a cross-linking polymeric network as a self-healing binder for Si anode is developed by in situ polymerization of tannic acid (TA) and polyacrylic acid (PAA) binder labelled as TA-c-PAA. The branched TA as a physical cross-linker complexes with PAA main chains through abundant dynamic hydrogen bonds, endowing the cross-linking TA-c-PAA binder with unique self-healing property and strong adhesion for Si anode. Benefiting from the mechanical robust and hard adhesion, the Si@TA-c-PAA electrode exhibits high reversible specific capacities (3250 mAh/g at 0.05C (1C = 4000 mA g−1)), excellent rate capability (1599 mAh/g at 2C), and impressive cycling stability (1742 mAh/g at 0.25C after 450 cycles). After Ex situ morphology characterization, in situ swelling analysis, and finite element simulation, it is found that the TA-c-PAA binder allows the Si anode to dissipate stress and prevent pulverization during lithiation and delithiation, thus the hydrogen bonds among interpenetrating network may be adaptable to the stress intensity. Our work paves a new avenue for the design of efficient and cost-effective binders for next-generation Si anode in LIBs.

Performance of passive direct formate fuel cells with foamed metal anode

Direct formate fuel cells (DFFCs) are recently attracting more attention, primarily because of the use of the carbon-neutral fuel, the low-cost catalyst and membrane. For improving the passive DFFC cell performance, passive, anion-exchange membrane (AEM) DFFCs were developed in this study using Ni foam as anode diffusion layer (DL) on which the catalyst slurry was coated with three different techniques, including direct brushing (DB), dripping (DR) and dip coating (DC). The catalysts on cathode and anode of the AEM DFFCs were Pt and Pd, respectively, with identical loading of 2 mg/cm2. Nafion was used as anode binder with loading of 1.87 mg/cm2. Both V–I curves and electrochemical impedance spectroscopy (EIS) of those passive AEM DFFCs were measured and investigated with the mixture of potassium formate (HCOOK) and potassium hydroxide (KOH) as anolyte at room temperature. Besides, the micrographs of the catalyst-coated Ni foams were also presented to inspect the catalyst distribution on the DL. An additional cell using traditional carbon cloth as DL was also tested for comparison. The polarization curves and EIS showed that the mass transport to the catalyst layer was significantly enhanced for those cells using Ni foam as DL, compared to the carbon cloth-based passive, AEM DFFC. Besides, the performance of the Ni foam-based DFFC with anode catalyst coated by DC technique was the best among all, while the cell possessing carbon cloth-based anode yielded the lowest maximum power density, 22.5 mW/cm2. The maximum power density of the passive AEM DFFC in this study reached 37.7 mW/cm2 when the cell having Ni foam anode made by DC method was fed with the mixture of 3 M HCOOK in 3 M KOH as liquid fuel. The results suggested that not only the mass transport loss but the activation loss can be lowered with appropriate catalyst distribution over the skeleton of the Ni foam.

A Multifunctional Interlocked Binder with Synergistic In Situ Covalent and Hydrogen Bonding for High-Performance Si Anode in Li-ion Batteries.

Silicon has garnered significant attention as a promising anode material for high-energy density Li-ion batteries. However, Si can be easily pulverized during cycling, which results in the loss of electrical contact and ultimately shortens battery lifetime. Therefore, the Si anode binder is developed to dissipate the enormous mechanical stress of the Si anode with enhanced mechanical properties. However, the interfacial stability between the Si anode binder and Cu current collector should also be improved. Here, a multifunctional thiourea polymer network (TUPN) is proposed as the Si anode binder. The TUPN binder provides the structural integrity of the Si anode with excellent tensile strength and resilience due to the epoxy-amine and silanol-epoxy covalent cross-linking, while exhibiting high extensibility from the random coil chains with the hydrogen bonds of thiourea, oligoether, and isocyanurate moieties. Furthermore, the robust TUPN binder enhances the interfacial stability between the Si anode and current collector by forming a physical interaction. Finally, the facilitated Li-ion transport and improved electrolyte wettability are realized due to the polar oligoether, thiourea, and isocyanurate moieties, respectively. The concept of this work is to highlight providing directions for the design of polymer binders for next-generation batteries.

Gum based functional binder for high-performance artificial graphite anode for lithium-ion batteries

Artificial graphite (AG), in contrast to natural graphite, has received much attention due to its superior rate capabilities and stability under high current density. Although the rate capabilities can be enhanced by employing artificial graphite, there is room for improvement in the cycle retention characteristics of artificial graphite. In particular, further optimization on the binder type on anodes is necessary, as commercially used polyvinylidene fluoride (PVdF) has limitations in long-term cycling stability. Furthermore, PVdF is dissolved in N-Methyl-2-pyrrolidone (NMP), which is not environmentally- and eco-friendly. In this work, we have introduced a water-soluble binder based on deacetylated kondagogu gum (KG) for AG anodes, which are derived from the gum tree. Upon deacetylation, kondagogu gum can be dissolved in water, which can be directly used together with active materials and conductive agents in a slurry. Replacing a PVdF binder with a KG binder results in an enhanced cycle retention and comparable rate capabilities, without the changes in the overall redox reactions with Li+. Postmortem analysis reveals that the improved electrochemical performance of the AG anode contributed to the excellent structural integrity of the KG binder compared with the PVdF binder.

Prelithiated rigid polymer with high ionic conductivity as silicon-based anode binder for lithium-ion battery

Silicon-based electrodes suffer from rapid performance degradation derived from a severe volume expansion during cycling in lithium-ion batteries, and using elaborately designed polymer binders is deemed an efficient tactic to tackle the above thorny issues. In this study, a water-soluble rigid-rod poly(2,2′-disulfonyl-4,4′-benzidine terephthalamide) (PBDT) polymer is described and employed as the binder for Si-based electrodes for the first time. The nematic rigid PBDT bundles wrapped around the Si nanoparticles by hydrogen bonding effectively inhibit the volume expansion of the Si and promote the formation of stable solid electrolyte interfaces (SEI). Moreover, the prelithiated PBDT binder with high ionic conductivity (3.2 × 10−4 S cm−1) not only improves the Li-ions transportation behaviors in the electrode but can also partially compensate for the irreversible Li source consumption during SEI formation. Consequently, the cycling stability and initial coulombic efficiency of the Si-based electrodes with the PBDT binder are remarkably enhanced compared to that with the PVDF binder. This work demonstrates the molecular structure and prelithiation strategy of the polymer binder that play a crucial role in improving the performance of Si-based electrodes with high-volume expansion.

Application and Development of Silicon Anode Binders for Lithium-Ion Batteries.

The use of silicon (Si) as a lithium-ion battery's (LIBs) anode active material has been a popular subject of research, due to its high theoretical specific capacity (4200 mAh g-1). However, the volume of Si undergoes a huge expansion (300%) during the charging and discharging process of the battery, resulting in the destruction of the anode's structure and the rapid decay of the battery's energy density, which limits the practical application of Si as the anode active material. Lithium-ion batteries' capacity, lifespan, and safety can be increased through the efficient mitigation of Si volume expansion and the maintenance of the stability of the electrode's structure with the employment of polymer binders. The main degradation mechanism of Si-based anodes and the methods that have been reported to effectively solve the Si volume expansion problem firstly are introduced. Then, the review demonstrates the representative research work on the design and development of new Si-based anode binders to improve the cycling stability of Si-based anode structure from the perspective of binders, and finally concludes by summarizing and outlining the progress of this research direction.

Performance of passive direct formate fuel cells using chitosan as an anode binder

ABSTRACT In this study, passive anion-exchange membrane (AEM) direct formate fuel cells (DFFCs) were developed and tested. Passive DFFCs consist of a fuel reservoir attached to a Pd-loaded anode, a commercially available AEM, and an air-breathing Pt-loaded cathode. Nafion or chitosan content of 22, 15, 10, or 5 wt% was blended with the anode catalyst ink as electrode binders. The polarization curves of the cells and Cyclic Voltammetry (CV) curves of the anodes were measured under different analyte compositions by mixing HCOOK and KOH with the molarity ranging from 1 M to 7 M at room temperature. The results showed that the ECSA values of the anode increased with the decrease in the binder content regardless of the binder type. The 15 wt% Nafion-based and 5 wt% chitosan-based passive AEM DFFCs fed with fuel containing 3 M HCOOK in 3 M KOH produced the highest maximum power density of 24.9 mW/cm2 and 27.5 mW/cm2, respectively. Finally, the current output of discharging of the 5 wt% chitosan-based passive AEM DFFCs at 0.4 V for 10 hr showed that providing the cell with more concentrated fuel produced more stable current as the concentrations of HCOOK and KOH are identical.