Various synthetic and bioinspired, linear, and 3D network polymeric binders have been developed to suppress the shuttle effect and improve the cyclability of Li-S batteries. [10][11][12][13][14][15] Synthetic binders, such as polyvinylidene fluoride (PVDF), bind conductive materials (carbon black and super P) well via hydrophobic interaction, but they usually show poor adhesion with active materials (S/Li 2 S n ). [16,17] As a comparison, bio-derived binders with functional groups, such as hydroxyl, carboxyl, and amino groups, show the excellent dispersing property to active materials due to the strong dipolar/hydrogen bonding interaction, [13,15,18,19] but the weak interaction with conductive materials still impede their application for sulfur cathodes. In addition, these bio-derived polymer binders are mostly watersoluble (hydrophilic), while the conductive additives are hydrophobic, which is the main obstacle to their interactions. [16,20,21] Few binders match both of the above two binders, and the poor dispersibility of their mixtures usually causes severe aggregation, which makes binders hardly play the role unless the dosage achieves as high as 10 wt% or even in an extreme case of 20 wt%. [22][23][24] Excessive binders in electrodes will limit the battery's energy density and significantly increase the bulk resistance of the whole battery. [21,25,26] In addition, most binders show poor adhesion between active/conductive mixture and current collector, especially after electrolyte wetting, which further increases binder usage. [27] It is urgent to develop binders with broad-spectrum and strong adhesion and good dispersibility to reduce dosages, such as ≤2 wt% as that in commercial Li-S batteries, and improve sulfur utilization, as well as electrochemical stability, and then inspire the theoretical specific energy and high rate performance of Li-S batteries.Fortunately, nature gives us solutions to address previously mentioned issues. As the second most abundant component in plants, lignin is a unique aromatic polymer composed of three p-hydroxyphenylpropane units connected by CO and CC bonds. [28][29][30] Lignin not only binds cellulose with hemicellulose via hydrogen bonding but also plays important role in stress resistance based on its macromolecular aromatic skeleton. [31,32] The distribution and role of lignin in plants are almost the same as those of binders in the cathode of Li-S batteries, which makes lignin an ideal binder candidate for Li-S batteries (Figure 1). Lignin can absorb active materials through carboxyl and hydroxyl groups, interact with conductive additives via the aromatic rings, and constrain the shuttle effect Polymeric binders stabilize lithium-sulfur (Li-S) batteries by suppressing the shuttle of lithium polysulfide (LiPS) and volume variation, but the dosage of state-of-the-art binders in sulfur cathodes (≈20 wt%) hinders the electron/ion transfer and decreases the cell-specific density. Here, a wood-inspired lignin binder is developed after modification with amino acids for pract...

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The increasing preference for minimally invasive surgery requires novel soft materials that are injectable, with rapid self-healing abilities, and biocompatible. Here, by utilizing the synergetic effect of hydrophobic interaction and quadruple hydrogen bonding, an injectable supramolecular hydrogel with excellent self-healing ability was synthesized. A unique ABA triblock copolymer was designed containing a central poly(ethylene oxide) block and terminal poly(methylmethacrylate) (PMMA) block, with ureido pyrimidinone (UPy) moieties randomly incorporated (termed MA-UPy-PEO-UPy-MA). The PMMA block could offer a hydrophobic microenvironment for UPy moieties in water and thus boost the corresponding quadruple hydrogen bonding interaction of Upy–Upy dimers. Owing to the synergetic effect of hydrophobicity and quadruple hydrogen bonding interaction, the obtained MA-UPy-PEO-UPy-MA hydrogel exhibited excellent self-healing properties, and injectable capability, as well as superior mechanical strength, and therefore, it holds great promise in tissue engineering applications, including in cell support and drug release.