A Self‐Healable Polyelectrolyte Binder for Highly Stabilized Sulfur, Silicon, and Silicon Oxides Electrodes

Chen

et al. 2022

Adv Funct Materials

The practical application of lithium-sulfur (Li-S) batteries is gravely hampered by the dissolution and shuttle of lithium polysulfides. Herein, a zwitterionic polymer binder with both lithiophilicity and sulfophilicity is skillfully designed to realize a synergistic regulation of cations and anions through the strong interactions with lithium polysulfides. The cationic quaternary ammonium group within the polymeric zwitterion can immobilize polysulfide anions and block polysulfide migration, while the sulfonate anions preferably couple with lithium ion, thus facilitating ion transfer and promoting the polysulfides redox kinetics. The dynamic networks crosslinked by both hydrogen bonding and electrostatic interaction enable mechanically robust cathodes to withstand the volume variation and spontaneously repair cracks upon repeated lithiation/delithiation. Benefiting from these attributes, the Li-S coin cell using the zwitterionic polymer binder delivers a high initial discharge capacity of 1230.6 mAh g −1 at 0.2 C as well as an ultralow capacity decay rate of 0.03% per cycle over 600 cycles at 2 C. In Li-S pouch cell level, a high areal capacity of 6.6 mAh cm −2 after 50 cycles can be obtained under a sulfur loading of up to 8.5 mg cm −2 , demonstrating the potential of zwitterionic polymer binder for the further development of high-performance Li-S batteries.

Section: Introductionmentioning

confidence: 99%

Synergistic Cation–Anion Regulation of Polysulfides by Zwitterionic Polymer Binder for Lithium–Sulfur Batteries

Chen

et al. 2022

Adv Funct Materials

“…In order to address the problem confronting Si anodes, existing approaches include structural modifications of Si materials (e.g., nanowires, nanosheets and hierarchical constructions), introduction of additives and the development of novel binders [ 3 – 8 ]. Among these strategies, the employment of advanced binders has been demonstrated to be a facile yet effective way without compromise in battery energy density [ 9 , 10 ]. Ideal binders should tolerate the volume expansion of Si particles upon cycling by relying on the reversibility of their bonding structure, thereby maintaining structural integrity of Si electrodes [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

An Endotenon Sheath-Inspired Double-Network Binder Enables Superior Cycling Performance of Silicon Electrodes

Jiang

Zhang

et al. 2022

Nano-Micro Lett.

Silicon (Si) has been regarded as an alternative anode material to traditional graphite owing to its higher theoretical capacity (4200 vs. 372 mAh g−1). However, Si anodes suffer from the inherent volume expansion and unstable solid electrolyte interphase, thus experiencing fast capacity decay, which hinders their commercial application. To address this, herein, an endotenon sheath-inspired water-soluble double-network binder (DNB) is presented for resolving the bottleneck of Si anodes. The as-developed binder shows excellent adhesion, high mechanical properties, and a considerable self-healing capability mainly benefited by its supramolecular hybrid network. Apart from these advantages, this binder also induces a Li3N/LiF-rich solid electrolyte interface layer, contributing to a superior cycle stability of Si electrodes. As expected, the DNB can achieve mechanically more stable Si electrodes than traditional polyacrylic acid and pectin binders. As a result, DNB delivers superior electrochemical performance of Si/Li half cells and LiNi0.8Co0.1Mn0.1O2/Si full cells, even with a high loading of Si electrode, to traditional polyacrylic acid and pectin binders. The bioinspired binder design provides a promising route to achieve long-life Si anode-assembled lithium batteries. "Image missing"

“…In the battery community, it is known that one of the most effective ways to address the issues stemming from the volume change of the electrode material is to use a highly elastic binder. − With this rationale in mind, in this study, a highly stable polymeric binder for silver–carbon composite electrodes was developed to promote electrode stability and to lower the initial irreversibility. PVDF was usually used as a binder in silver–carbon composite electrodes because of its well-known advantages of high dielectric constant and (electro)chemical stability. , PVDF has also been used as a main component in the artificial SEI layer by taking advantage of its high dielectric constant. , However, it is not suitable for use with electrodes comprising active materials that experience large volume changes such as silicon anodes as a result of the weak adhesion force and plastic deformation .…”

mentioning

confidence: 99%

Elastic Binder for High-Performance Sulfide-Based All-Solid-State Batteries

Choi

Chang

et al. 2022

ACS Energy Lett.

Sulfide-based all-solid-state batteries (ASSBs) offer enhanced safety and potentially high energy density. Particularly, an “anode-less” electrode containing metallic seeds that form a solid-solution with lithium was recently introduced to improve the cycle life of sulfide-based ASSB cells. However, this anode-less electrode is gradually destabilized because the metal particles undergo severe volume expansion during repeated cycling. Furthermore, the irreversibility of the electrode in early cycles impairs the energy density of the cell significantly. Herein, we introduce an elastic polymer known as “Spandex” as a binder for the silver–carbon composite. The soft and hard segments of this binder act synergistically in that the former engages in strong hydrogen bonding with the active material and the latter promotes elastic adjustment of the binder network. This binder design significantly improves the charge–discharge reversibility and long-term cyclability of the anode-less ASSB cell and provides insights into elastic binder systems for high-capacity ASSB anodes that undergo a large volume expansion.