Highly Stretchable Polymer Binder Engineered with Polysaccharides for Silicon Microparticles as High-Performance Anodes

Poly(Acrylic Acid)-Based Polymer Binders for High-Performance Lithium-Ion Batteries: From Structure to Properties

Poly(acrylic acid) (PAA) and its derivatives have emerged as promising candidates for enhancing the electrochemical performance of lithium-ion batteries (LIBs) as binder materials. Recent research has focused on evaluating their ability to improve adhesion with silicon (Si) particles and facilitate ion transport while maintaining electrode integrity. Various strategies, including mixing modifications and copolymerization methods, are highlighted and the structural and physicochemical properties of these binders are examined. Additionally, the interaction mechanisms between PAA-based binders and active materials and their impact on key electrochemical properties such as initial Coulombic efficiency (ICE) and cycle stability are discussed. The findings underscore the efficacy of tailored PAA-based binders in enhancing the electrochemical properties of LIBs, offering insights into the design principles and practical implications for advanced battery materials. These advancements hold promise for developing high-performance lithium batteries capable of meeting future energy storage demands.

Highly Stretchable Thermoplastic Polyurethane Separators for Li-Ion Batteries Based on Non-Solvent-Induced Phase Separation Method

The growing interest in wearable and portable devices has stimulated the need for flexible and stretchable lithium-ion batteries (LiBs). A crucial component in these batteries is the separator, which provides a pathway for Li-ion transfer and prevents electrode contact. In a flexible and stretchable LiB, the separator must exhibit stretchability and elasticity akin to its existing counterparts. Here, we developed a non-modified thermoplastic polyurethane (TPU) separator using the non-solvent induced phase separation (NIPS) technique. We compared their performance with commercially available polypropylene (PP) separators. Our results demonstrate that TPU separators exhibit superior elasticity based on repeated stretch/release tests with excellent thermal stability and electrolyte wettability. Furthermore, our findings confirm that TPU separators, even after being repeatedly stretched and released, can function effectively without severe damage in a fabricated coin cell LiB with high oxidative stability, as evidenced by linear sweep voltammetry, like commercially available separators.

Slidable and Highly Ionic Conductive Polymer Binder for High-Performance Si Anodes in Lithium-Ion Batteries

Silicon is expected to become the ideal anode material for the next generation of high energy density lithium battery because of its high theoretical capacity (4200 mAh g-1 ). However, for silicon electrodes, the initial coulombic efficiency (ICE) is low and the volume of the electrode changes by over 300% after lithiation. The capacity of the silicon electrode decreases rapidly during cycling, hindering the practical application. In this work, a slidable and highly ionic conductive flexible polymer binder with a specific single-ion structure (abbreviated as SSIP) is presented in which polyrotaxane acts as a dynamic crosslinker. The ionic conducting network is expected to reduce the overall resistance, improve ICE and stabilize the electrode interface. Furthermore, the introduction of slidable polyrotaxane increases the reversible dynamics of the binder and improves the long-term cycling stability and rate performance. The silicon anode based on SSIP provides a discharge capacity of ≈1650 mAh g-1 after 400 cycles at 0.5C with a high ICE of upto 92.0%. Additionally, the electrode still exhibits a high ICE of 87.5% with an ultra-high Si loading of 3.84 mg cm-2 and maintains a satisfying areal capacity of 5.9 mAh cm-2 after 50 cycles, exhibiting the potential application of SSIP in silicon-based anodes.

Application of Guar Gum and its Derivatives as Green Binder/Separator for Advanced Lithium-Ion Batteries

Since their first commercialization in the 1990s,lithium-ion batteries (LIBs) have become an indispensible part of our everyday life in particular for portable electronic devices. LIBs have been considered as the most promising sustainable high energy density storage device. In recent years, there is a strong demand of LIBs for hybrid electric and electric vehicles to lower carbon footprint and mitigate climate change. However, LIBs have several issues, for example, high cost and safety issues such as over discharge, intolerance to overcharge, high temperature operation etc. To address these issues several new types of electrodes are being studied. Traditional binder PVDF is costly, difficult to recyle, undergoes side reactions at high temperature and cannot stabilize high energy density electrodes. To overcome these challenges, diiferent binders have been introduced with these electrodes. This minireview is focused on the application of guar gum as a binder for different electrodes and separator. The electrochemical performance of electrodes with guar gum has been compared with other binders.

Binary Network of Conductive Elastic Polymer Constraining Nanosilicon for a High-Performance Lithium-Ion Battery

Silicon-based anodes are attracting more interest in both science and industry due to their high energy density. However, the traditional polymeric binder and carbon additive mixture cannot successfully accommodate the huge volume change and maintain good conductivity when cycling. Herein, we report a multifunctional polymeric binder (PPTU) synthesized by the cross-linking of conducting polymer (PEDOT:PSS) and stretchable polymer poly(ether-thioureas) (PETU). The multifunctional polymeric binder could be curved on the surfaces of nanosilicon particles, forming an interweaving continuous three-dimensional network, which is beneficial to electron transfer and the mechanical stability. Furthermore, the binder is elastic and adhesive, and which can accommodate the huge volume change of silicon to keep its integrity. Utilizing this multifunctional polymeric binder instead of commercial poly(acrylic acid) binder and carbon black mixtures, the nanosilicon anode demonstrates enhanced cycling stability (2081 mAhg^-1 after 300 cycles) and rate performance (908 mAhg^-1 at 8 Ag^-1). The multifunctional polymeric binder has high conductivity, elasticity, and self-healing properties is a promising binder to promote progress toward a high performance lithium-ion battery.

A Nanowire Nest Structure Comprising Copper Silicide and Silicon Nanowires for Lithium-Ion Battery Anodes with High Areal Loading

High loading (>1.6 mg cm^-2 ) of Si nanowires (NWs) is achieved by seeding the growth from a dense array of Cu₁₅ Si₄ NWs using tin seeds. A one-pot synthetic approach involves the direct growth of CuSi NWs on Cu foil that acts as a textured surface for Sn adhesion and Si NW nucleation. The high achievable Si NW loading is enabled by the high surface area of CuSi NWs and bolstered by secondary growth of Si NWs as branches from both Si and CuSi NW stems, forming a dense Si active layer, interconnected with an electrically conducting CuSi array (denoted Si/CuSi). When employed as Li-ion battery anodes, the Si/CuSi nest structure demonstrates impressive rate performance, reaching 4.1 mAh cm^-2 at C/20, 3.1 mAh cm^-2 at C/5, and 0.8 mAh cm^-2 at 6C. Also, Si/CuSi shows remarkable long-term stability, delivering a stable areal capacity of 2.2 mAh cm^-2 after 300 cycles. Overall, complete anode fabrication is achieved within a single reaction by employing an inexpensive Sn powder approach.

Polysaccharides for sustainable energy storage - A review

The increasing amount of electric vehicles on our streets as well as the need to store surplus energy from renewable sources such as wind, solar and tidal parks, has brought small and large scale batteries into the focus of academic and industrial research. While there has been huge progress in performance and cost reduction in the past years, batteries and their components still face several environmental issues including safety, toxicity, recycling and sustainability. In this review, we address these challenges by showcasing the potential of polysaccharide-based compounds and materials used in batteries. This particularly involves their use as electrode binders, separators and gel/solid polymer electrolytes. The review contains a historical section on the different battery technologies, considerations about safety on batteries and requirements of polysaccharide components to be used in different types of battery technologies. The last sections cover opportunities for polysaccharides as well as obstacles that prevent their wider use in battery industry.