High-Performance Self-Healing Polyurethane Binder Based on Aromatic Disulfide Bonds and Hydrogen Bonds for the Sulfur Cathode of Lithium–Sulfur Batteries

Abstract

Lithium−sulfur (Li−S) batteries have been the focus of new energy due to their excellent energy density, but the large volume changes in sulfur cathodes and the shuttle of polysulfides seriously hinder their further development. Therefore, solving both the abovementioned problems is the key to the widespread applications of Li−S batteries. Here, a smart selfhealing polyurethane binder (PUB) with sulfur fixation ability is successfully developed for sulfur cathodes. In this design, aromatic disulfide bonds are introduced into the PUB matrix and cooperated with hydrogen bonds in the matrix to provide the self-healing property. The PUB can ensure the sulfur cathode an integrated physical structure by autonomously healing the microcracks caused by volume changes. The sulfur-fixing groups in the PUB can effectively absorb the polysulfides in the electrochemical reaction to suppress the shuttling effect. As a result, the Li−S batteries exhibit a high electrochemical capacity of 1269.7 mA h g −1 and a small fading rate of 0.04% per cycle at 2 C for 500 cycles. Hence, the PUB with dual functions of self-repair and sulfur fixation can effectively stabilize the electrode structures of Li−S batteries and guarantee their electrochemical performance.

Self-Healing Polyurethane Elastomers with High Mechanical Properties Based on Synergistically Thermo-Reversible and Quadruple Hydrogen Bonds

“…It is necessary to introduce dynamic covalent bonds or noncovalent bonds into the molecular structure of PU to achieve internal chemical stability and exchangeability. Such noncovalent bonds include hydrogen bonds, − metal coordination bonds, , and π–π interactions and dynamic covalent bonds include Diels–Alder (D–A) thermally reversible covalent bonds, , dynamic reversible imine bonds, ,− acylhydrazone bonds, and disulfide bonds . Noncovalent bonds have good reversibility, sensitivity, and physical cross-linking ability and are often introduced into PU hard domains to construct noncovalent polymers.…”

Self-Healable, Recyclable, and Reprocessable Poly(urethane–urea) Elastomers with Tunable Mechanical Properties Constructed by Incorporating Triple Dynamic Bonds

“…Accordingly, the intrinsic self-healing based on reversible covalent bonds including disulfide bonds, , polysulfides bonds, boronic ester, − Diels–Alder addition, − acylhydrazone, hindered urea bonds, , oxime–carbamate bonds, and dynamic noncovalent bonds such as H bonds, − coordination bonds, − or combinations of them have been widely reported. ,,, For instance, some polyurethane elastomers containing aromatic disulfides show efficient self-healing at room temperature because the disulfide metathesis reaction occurs readily at room temperature without external stimulation . The highest tensile strength and toughness of this elastomer, however, were 6.8 MPa and 26.9 MJ m –3 , respectively.…”

An Autonomously Self‐Healing Silicone Polyurea Waterproof Coating for Combustible Cartridge Cases

“…Self-healing polymer materials (SHPMs), as a class of intelligent bionic materials, can autonomously heal the mechanical microcracks generated in their matrices [8][9][10]. SHPMs have attracted much attention in recent years [11][12][13], exhibiting tremendous application prospects in artificial skin [14,15], coatings [6,16], binders [17,18], and other fields [19,20]. To date, SHPMs can be divided into two categories, extrinsic and intrinsic types, according to their selfhealing mechanisms [9].…”