Multifunctional Binder 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.

PTFE as a Multifunctional Binder for High-Current-Density Oxygen Evolution.

Binder plays a crucial role in constructing high-performance electrodes for water electrolysis. While most research has been focused on advancing electrocatalysts, the application of binders in electrode design has yet to be fully explored. Herein, the in situ incorporation of polytetrafluoroethylene (PTFE) as a multifunctional binder, which increases electrochemical active sites, enhances mass transfer, and strengthens the mechanical and chemical robustness of oxygen evolution reaction (OER) electrodes, is reported. The NiFe-LDH@PTFE/NF electrode prepared by co-deposition of PTFE with NiFe-layered double hydroxide onto nickel foam demonstrates exceptional long-term stability with a minimal potential decay rate of 0.034mV h-1 at 500mA cm-2 for 1000 h. The alkaline water electrolyzer utilizing NiFe-LDH@PTFE/NF requires only 1.584V at 500mA cm-2 and sustains high energy efficiency over 1000 h under industrial operating conditions. This work opens a new path for stabilizing active sites to obtain durable electrodes for OER as well as other electrocatalytic systems.

A Self-Healing Polymer Binder of Silicon-Based Anode with Enhanced Lithium-Ion Transport Performance

A multi-functional binder was designed for silicon-based anode lithium-ion battery to alleviate the huge volume expansion of silicon anode during the process of charging and discharging, and to provide ion transport channels to improve the rate performance of electrodes to meet the needs of rapid charging and discharging. In this study, a binder PAA-TUEG which combined the mechanical properties of PAA, the fast self-healing ability provided by the zigzag hydrogen bond in TUEG, and the ion transport ability provided by the ether-oxygen group was synthesized. The effect of different proportion of TUEG binder on the electrochemical performance of the electrode was further investigated. The synthesized PAA-TUEG5% polymer material exhibits a tensilestrength of 0.8 MPa and a fracture elongation of 397%. The Si@PAA-TUEG5% electrode demonstrates reversible capacities of 3035, 2260, and 1249 mAh g−1 at 0.5, 1, and 2 C (1 C = 3500 mAh g−1), respectively. In extended cycling tests, the remaining capacities after 180 cycles at 0.5 and 1 C are 852 and 793 mAh g−1, respectively. This innovative binder, featuring both self-healing ability and enhanced ion transport through dynamic reversible hydrogen bond and ionic bond, presents a promising design concept for the next generation of high-energy-density lithium-ion batteries.

Coal-based hard carbon anode for high-performance sodium ion batteries via coal-based graphene oxide as a multi-functional binder

Coal-based hard carbon for sodium ion batteries (SIBs) was successfully prepared using Shenfu bituminous coal (SFC) by one-step pyrolysis method. In the present work, we reported a novel method to fabricate carbon electrodes for SIBs from coal-based hard carbon with coal-based graphene oxide (CGO) as a multi-functional conductive binder to realize dual functional utilization of coal. As compared to traditional binder (CMC), electrodes with the CGO binder exhibits significantly increased reversible capacity and rate capability. This work provides a facile method for coal-based carbon materials used in SIBs.

Water‐Soluble Multifunctional Binder with Extraordinary Bonding Strength for High‐Voltage Sodium‐Ion Batteries

AbstractWith the ever‐increasing demand for low‐cost energy storage systems, sodium‐ion (Na‐ion) batteries have received great attention. However, the large volume change, sluggish reaction kinetics, and unstable electrode/electrolyte interphase during cycling inevitably deteriorate the performance of Na‐ion batteries. Herein, a high‐voltage water‐soluble multifunctional binder with an extraordinary bonding strength is investigated. Such water‐soluble binder not only exhibits an excellent adhesion strength to maintain the mechanical integrity and enhance the Na‐ion diffusion across the interfac but also constructs a robust protective layer to prevent side reactions and improve the cycle durability at high voltages. As a result, a specific capacity of 91.3 mAh g−1 at 10.0C and high capacity retention of 92.3% for 1000 cycles are achieved. A good cycle stability and rate performance between 2.5 and 4.4 V can be observed after pairing with a high‐voltage electrode, and the practical application of the high‐voltage water‐soluble multifunctional binder is further confirmed by a 0.95 Ah Na‐ion pouch cell.

Greener, Safer and Better Performing Aqueous Binder for Positive Electrode Manufacturing of Sodium Ion Batteries.

P2-type cobalt-free MnNi-based layered oxides are promising cathode materials for sodium-ion batteries (SIBs) due to their high reversible capacity and well chemical stability. However, the phase transformations during repeated (dis)charge steps lead to rapid capacity decay and deteriorated Na+ diffusion kinetics. Moreover, the electrode manufacturing based on polyvinylidene difluoride (PVDF) binder system has been reported with severely defluorination issue as well as the energy intensive and expensive process due to the use of toxic and volatile N-methyl-2-pyrrolidone (NMP) solvent. It calls for designing a sustainable, better performing, and cost-effective binder for positive electrode manufacturing. In this work, we investigated inorganic sodium metasilicate (SMS) as a viable binder in conjunction with P2-Na0.67Mn0.55Ni0.25Fe0.1Ti0.1O2 (NMNFT) cathode material for SIBs. The NMNFT-SMS electrode delivered a superior electrochemical performance compared to carboxy methylcellulose (CMC) and PVDF based electrodes with a reversible capacity of ~161 mAh/g and retaining ~83 % after 200 cycles. Lower cell impedance and faster Na+ diffusion was also observed in this binder system. Meanwhile, with the assistance of TEM technique, SMS is suggested to form a uniform and stable nanoscale layer over the cathode particle surface, protecting the particle from exfoliation/cracking due to electrolyte attack. It effectively maintained the electrode connectivity and suppressed early phase transitions during cycling as confirmed by operando XRD study. With these findings, SMS binder can be proposed as a powerful multifunctional binder to enable positive electrode manufacturing of SIBs and to overall reduce battery manufacturing costs.

Enhanced lithium-ion storage of the SiOx@C anode enabled by carbon coating coupled with MXene as a conductive binder

The MXene as a multi-functional binder, together with the carbon coating, endows the SiOx anode with excellent lithium-ion storage performance.

A multifunctional binder capable of harvesting light, electronic transport, and photocharging a lithium-ion photobattery

Poly(perylenediimide-alt-ethylene oxide) was prepared as a multifunctional lithium-ion battery binder. Upon light harvesting, the binder oxidized LiFePO4 and subsequently injected an electron into the circuit for potential solar conversion and storage.

(Invited) A Multifunctional Polynorbonene Binder System Enabling Next-Generation Lithium-Ion Batteries

Polynobornene (PNBE), a material commonly used in your shoes or for the tires of supercars, can also be highly influential to the development of next-generation batteries (Kim et al., 2022). When designing the batteries of tomorrow, we are interested in polymeric materials with precisely defined dynamic mechanical properties, increased ionic or conductivity, specific chemical interactions and moonshots like stable and healable interfaces (Lopez et al., 2019). PNBE provides high chemical and thermal stability, low shrinkage, and strong adhesion properties that lead to enhanced electrode stability and electrical conductivity(Le et al., 2020). Possessing a highly flexible nature allows PNBE to conform to the shape of an electrode – making PNBE an ideal multifunctional binder.Consider some persisting problems associated with batteries, for example Si electrodes typically fail due to cracks in the Si particles creating new surfaces for electrolyte decomposition/solid electrolyte interphase formation, and due to the Si becoming electrically disconnected from the rest of the electrode and ultimately terminating cycling (Ryu et al., 2004) . PNBE can address both aforementioned pain points, low shrinkage and flexibility can help mitigate the impact of cracking that occurs within an electrode over time by maintaining the structural integrity, and strong adhesion properties promote effective binding of the active material and the rest of the electrode. With increasing concerns about cobalt, there has been a move to replace oxides with phosphates. Substituting a substantial fraction of Mn, for Fe in LiFePO4 leads to a material with an energy density approaching that of the oxides, while substantially lessening environmental concerns. Unfortunately, Mn dissolution causes a poor cycle lifetime.In an effort to reduce Mn dissolution, a mixture of PNBE and PVDF was used as a binder system. The PNBE was designed to have ether-type comb-branch functionalities that aid in Mn trapping, while the PVDF had suitable viscosity and mechanical properties. Figure 1 shows cycle lifetime results conducted at 45°C on a 2Ah LMFP-Graphite cell containing a 4%PVDF/1%PNBE binder system. The results show very good lifetime, with the capacity retention nearly 90% after 1,000 cycles. Given the difficulty with cycling of LMFP due to Mn dissolution, these results show good promise for this approach.This talk will highlight the opportunities and challenges of custom and enabling PNBE binder systems for LMFP, and other battery systems. References Kim, N.-Y., Moon, J., Ryou, M.-H., Kim, S.-H., Kim, J.-H., Kim, J.-M., Bang, J., & Lee, S.-Y. (2022). Amphiphilic Bottlebrush Polymeric Binders for High-Mass-Loading Cathodes in Lithium-Ion Batteries. Advanced Energy Materials, 12(1), 2102109. https://doi.org/https://doi.org/10.1002/aenm.202102109Le, D., Samart, C., Lee, J.-T., Nomura, K., Kongparakul, S., & Kiatkamjornwong, S. (2020). Norbornene-Functionalized Plant Oils for Biobased Thermoset Films and Binders of Silicon-Graphite Composite Electrodes. ACS Omega, 5(46), 29678–29687. https://doi.org/10.1021/acsomega.0c02645Lopez, J., Mackanic, D. G., Cui, Y., & Bao, Z. (2019). Designing polymers for advanced battery chemistries. Nature Reviews Materials, 4(5), 312–330. https://doi.org/10.1038/s41578-019-0103-6Ryu, J. H., Kim, J. W., Sung, Y.-E., & Oh, S. M. (2004). Failure Modes of Silicon Powder Negative Electrode in Lithium Secondary Batteries. Electrochemical and Solid-State Letters, 7(10), A306. https://doi.org/10.1149/1.1792242 Figure 1

A unique redox active ion-electron conductor enabled 5C fast-charging graphite anode for lithium-ion batteries

Enhancing the charging rate of lithium-ion batteries is poised to accelerate the rapid promotion of electric vehicles, decrease greenhouse gas emissions, and reduce the energy crisis worldwide. However, during the fast-charging process, the slow transport of ions and electrons in the graphite anode makes it challenging to achieve a high capacity and good reversible capability. A multifunctional binder that can realize redox reactions with excellent ionic/electronic conduction is reported herein. The electronic/ionic conductance composition is analyzed for the Li-SPODs binder. Thereinto, the total conductivity of Li-SPODs (0.82 mS cm−1) is divided into three parts: lithium sulfonate ionic conductivity (0.54 mS cm−1) in the eigenstate state, electronic conductivity (1.7 × 10−4 mS cm−1) in the doped state, and doping lithium ionic conductivity(0.27 mS cm−1) in the doped state. The conductivity splitting of Li-SPODs binder can reveal the distinct effect of both conductances on graphite electrodes. Benefiting from the high conductive Li-SPODs binder, the contact resistance of the graphite electrode decreased by 54.4 % compared to the carboxymethyl cellulose/butadiene styrene rubber (CMC/SBR) binder. Meanwhile, the full cell based on the lithium iron phosphate cathode and graphite anode (the areal capacity of 2 mAh cm−2) exhibits an extraordinary capacity and outstanding cycling stability (0.04 % capacity decay per cycle during 500 cycles) even at 5C. More importantly, this novel design strategy provides new insight into preparing a multifunctional binder for fast-charging electrodes with high power and energy.

An electrochemically transformed multifunctional binder network simultaneously strengthens the interphase stability and mechanical integrity of silicon anodes

Silicon (Si) is a promising alternative anode material for lithium-ion batteries due to its ultra-high theoretical capacity and suitable voltage platform. However, its practical application is limited by the rapid capacity fading caused by the instability of the solid electrolyte interphase (SEI) film, the collapse of Si particle structure and the mechanical failure of Si electrodes. Herein, we develop a multifunctional composite binder (denoted as PS) composed of multi-hydroxyl polyvinyl alcohol (PVA) and electroactive squaric acid (SA). The complete binder network derived from the efficient crosslinking reactions between SA and PVA chains, as well as the beneficial electrochemical synergistic decomposition reactions between SA and fluoroethylene carbonate additive, can effectively stabilize the macro- and micro-structures of Si electrodes, induce the beneficial decomposition components of electrolytes to build a robust SEI film, and promote the Li+ transport rate. Based on these beneficial effects, the optimized PS61-based Si anode exhibits higher initial coulombic efficiency (89.8 %), much improved rate performance (2041.5 mAh g−1 at 10 C), and better cycling stability (1582.1 mAh g−1 after 400 cycles) than that of the PVA-based Si anode. Furthermore, the NCM523//Si (PS61) full cell achieved a high reversible capacity of 140.8 mAh g−1 after 300 cycles, demonstrating the positive function of PS binder on promoting the practical application of Si anodes.

Multiple conductive network for KTi2(PO4)3 anode based on MXene as a binder for high-performance potassium storage

KTi2(PO4)3 is a promising anode material for potassium storage, but suffers from low conductivity and difficult balance between high capacity and good structural stability. Herein, the Ti3C2Tx MXene is used as a multifunctional binder to fabricate the KTi2(PO4)3 electrode by the traditional homogenizing-coating method. The MXene nanosheets, together with the conductive agent super P nanoparticles, construct a multiple conductive network for fast electron/ion transfer and high electrochemical kinetics. Moreover, the network ensures the structural stability of the KTi2(PO4)3 electrode during the de-intercalation/intercalation of 4 K+ ions, which is beneficial for simultaneously achieving high capacity and good cycle performance. Therefore, the MXene-bonded KTi2(PO4)3 electrode delivers a reversible capacity of 255.2 mAh/g at 50 mA/g, outstanding rate capability with 132.3 mAh/g at 2 A/g, and excellent cycle performance with 151.6 mAh/g at 1 A/g after 2000 cycles. This work not only suggests a high-performance anode material for potassium-ion batteries, but also demonstrates that the MXene is a promising binder material for constructing conductive electrodes in rechargeable batteries.

Dual Cross-Linked Multifunctional Binder for High-Performance Lithium–Sulfur Batteries

Dual Cross-Linked Multifunctional Binder for High-Performance Lithium–Sulfur Batteries

Alginate-Xylan Biopolymer as a Multifunctional Binder for 5 V High-Voltage LNMO Electrodes.

LiNi0.5Mn1.5O4 (LNMO) with a spinel structure is one of the most promising cathode materials choices for Li-ion batteries (LIBs). However, at a high operating voltages, the decomposition of organic electrolytes and the dissolution of transition metals, especially Mn(II) ions, cause unsatisfactory cycle stability. The initial application of a sodium alginate (SA)-xylan biopolymer as an aqueous binder aims to address the aforementioned problems. The SX28-LNMO electrode has a sizable discharge capacity, exceptional rate capability, and long-term cyclability with a capacity retention of 99.8% after 450 cycles at 1C and a remarkable rate capability of 121 mAh g-1 even at 10C. A more thorough investigation illustrated that SX28 binder provides a substantial adhesion property and generates a uniform (CEI) layer on the LNMO surface, suppressing electrolytes' oxidative decomposition upon cycling and improving LIB performances. This work highlights the potential of hemicellulose as an aqueous binder for 5.0 V high-voltage cathodes.

Review and Perspectives on Advanced Binder Designs Incorporating Multifunctionalities for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have received paramount attention as a next-generation energy storage device due to their remarkably high specific capacity (1675 mAh g–1), energy density (2600 Wh kg–1), and cost-effectiveness compared to the forefront lithium-ion batteries. However, certain issues still hamper the smooth working of Li–S batteries, which need to be addressed to fill the gap between fundamental research and commercialization. Polymer binders, as an inevitable part of the cathode structure, play a vital role in upholding the structural robustness and firmness of the electrode. However, conventional binders like PVDF are not capable of effectively accommodating the large volume changes within the electrode, facilitating electronic/ionic conductivity, entrapping the soluble polysulfide intermediates, and enhancing polysulfide redox kinetics. Therefore, novel multifunctional binder designs are adopted in Li–S batteries to tackle the above-mentioned issues. This review summarizes the recent progress in this research area employing advanced multifunctional polymer binders in Li–S batteries. The action of the binder through various mechanisms is discussed in detail. The role of binder is given immense attention in the emerging field of various energy storage devices, including Li–S batteries, and, thus, here discussed as well.

Cross-Linked Sodium Alginate as A Multifunctional Binder to Achieve High-Rate and Long-Cycle Stability for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) hold great promise owing to the naturally abundant sodium resource and high safety. The research focus of SIBs is usually directed toward electrode materials, while the binder as an important component is rarely investigated. Herein, a cross-linked sodium alginate (SA)/graphene oxide (GO) binder is judiciously designed to serve as a robust artificial interphase on the surface of both anode and cathode of SIBs. Benefiting from the cross-linking continuous network structure as well as the highly hydrophilic nature, the SA-GO binder possesses a large tensile strength of 197.7 Mpa and a high ionic conductivity of 0.136 mS cm-1 , superior to pure SA (93.8 Mpa, 0.025 mS cm-1 ). Moreover, the structural design of SA-GO binder exhibits a strong binding ability to guarantee structural integrity during cycling. To demonstrate its effectiveness, polyanion-type phosphates (e.g., Na3 (VO)2 (PO4 )2 F) and chalcogenides (e.g., MoS2 , VS2 ) are adopted as cathode and anode materials of SIBs, respectively. As compared to traditional binders (e.g., PVDF, SA), electrodes with the SA-GO binder exhibits significantly increased rate capability and cycling stability, such as Na3 (VO)2 (PO4 )2 F (40 C fast-charge, 84% capacity retention after 1000 cycles). This work highlights the role of novel aqueous-based binders in developing next-generation sodium-storage devices.

A semi-fluid multi-functional binder for a high-performance silicon anode of lithium-ion batteries.

Currently, a variety of binders are developed to inhibit the rapid capacity fading of Si. The Si anodes are mainly enhanced by the chemical bonding effect on the surface of conventional solid-state binders. However, with a huge volume change of silicon, solid binders are easily deactivated. Herein, a semi-fluid binder termed GPC is designed based on a viscoelastic crosslinking network with abundant active sites and self-healing performance. The backbone of the binder network is in situ synthesized using guar gum (GG), polyacrylic acid (PAA), and citric acid (CA). Serving as the flexible joints and the plasticizer of the network, CA small molecules remarkably improve the viscoelasticity of the binder to tolerate the volume change of Si via rearranging particles in the network during cycling. Moreover, CA can form a layer of surface coating on Si to stabilize the SEI for long-term electrochemical performance. As a result, the Si@GPC electrode shows excellent cycling stability and exhibits a superb capacity of 1292 mA h g-1 after 1000 cycles at 2 A g-1. This work illustrates the advantages and prospects of designing semi-fluid binders for high-performance batteries.

Self-Repairable Silicon Anodes Using a Multifunctional Binder for High-Performance Lithium-Ion Batteries.

Despite of extremely high theoretical capacity of Si (3579 mAh g-1 ), Si anodes suffer from pulverization and delamination of the electrodes induced by large volume change during charge/discharge cycles. To address those issues, herein, self-healable and highly stretchable multifunctional binders, polydioxythiophene:polyacrylic acid:phytic acid (PEDOT:PAA: PA, PDPP) that provide Si anodes with self-healability and excellent structural integrity is designed. By utilizing the self-healing binder, Si anodes self-repair cracks and damages of Si anodes generated during cycling. For the first time, it is demonstrated that Si anodes autonomously self-heal artificially created cracks in electrolytes under practical battery operating conditions. Consequently, this self-healable Si anode can still deliver a reversible capacity of 2312mAhg-1 after 100 cycles with remarkable initial Coulombic efficiency of 94%, which is superior to other reported Si anodes. Moreover, the self-healing binder possesses enhanced Li-ion diffusivity with additional electronic conductivity, providing excellent rate capability with a capacity of 2084 mAh g-1 at a very high C-rate of 5 C.

Multifunctional binder capable of promoting the reaction dynamics of wide temperature operable lithium-sulfur battery

Lithium-sulfur battery (Li-S battery) is regarded as one of the most promising next generation energy storage system due to high specific energy and low cost. However, the existing problems including the shuttle effect of lithium polysulfides (LiPSs) and the volume effect of active material during electrochemical process lead to rapid capacity attenuation and low Coulombic efficiency, which finally hinders the practical application of Li-S battery. Therefore, a multifunctional binder is developed in this work to address above issues. In our strategy, a cross-linked binder (named as PLG) is in-situ generated by the hydrogen-bonding interaction between polyacrylamide, locust bean gum and gellan gum, which is conducive to suppress the electrode volume variation by cross-linked network and anchor the LiPSs due to the abundant hydroxyl/amino groups in polymer backbone. Remarkably, the PLG based electrode presents the discharge capacity of 623.4 mAh/g at 0.2 C after 200 cycles, which is almost twice as high as that of PVDF counterpart (342 mAh/g). Most importantly, the cycling performance is demonstrated across a wide temperature range from 0 to 60 °C, high capacity of 516 mAh/g and 440 mAh/g are remained after long-term cycling, respectively. Furthermore, the lithium-ion diffusion influenced by binder is delicately analyzed using cyclic voltammetry at variable speeds and in-situ electrochemical impedance spectroscopy, PLG binder is conducive to improve the reaction kinetic of electrode due to generation of cross-linked structure. This research demonstrates promising performance of multifunctional polysaccharide-based binder for wide temperature operable lithium-sulfur batteries.

Nucleophilic ring-opening of thiocyclic carbonates: A scheme to prepare sulfhydryl-rich binders for high-performance lithium-sulfur batteries

Problems such as cathode collapse caused by volume change and shuttle effect of lithium polysulfides (LiPSs) limit the commercialization of Lithium-Sulfur (Li-S). Herein, we developed a sulfhydryl-containing multifunctional binder prepared by the nucleophilic ring-opening reaction of thiocyclic carbonates with amino groups. The binders (CNP-T and CNP-F) form sulfur-containing polymers with sulfur through the wet-slurry process, thereby effectively suppressing the shuttle effect. The abundant polar functional groups (e.g., -NH2, -CS(NH)-) in CNP-T and CNP-F can effectively adsorb LiPSs to weaken the shuttle effect, which is confirmed by both density functional theory (DFT) and experimental results. At the same time, their own hyperbranched network structure can also limit the volume change of the sulfur cathode. Therefore, the Li-S battery exhibits an initial specific capacity of 924.02 mAh/g and a decay rate of 0.033% when cycled at 1C for 500 cycles.