Owing to the ultrahigh theoretical energy density, all-solid-state lithium–sulfur batteries (ASSLSBs) are regarded as one of the most promising energy storage technologies. Among solid-state polymer electrolytes (SPEs), poly(ethylene oxide) (PEO) has been widely investigated due to its favorable mechanical and chemical stability. However, its practical application in ASSLSBs is hindered by several drawbacks, including high crystallinity, low ionic conductivity, and the polysulfide shuttling effect. In this study, we successfully synthesized a dynamically cross-linked polymer electrolyte (BPUSPE) incorporating cyclic boroxine moieties and hydrogen bonds via a straightforward polycondensation reaction. Owing to the synergistic effect of dynamic boroxine bonds and hydrogen bonding, the electrolyte exhibits remarkable self-healing properties, enhanced mechanical strength, and superior electrochemical performance. Specifically, BPUSPE achieves an ionic conductivity of 0.14 mS cm −1 at 60 °C and possesses a wide electrochemical stability window of up to 5.3 V. Moreover, the electrolyte demonstrates excellent self-healing capability, enabling full recovery of functionality after mechanical damage. Notably, the boron atoms in the cyclic boroxine units interact strongly with sulfur atoms in lithium polysulfides (LiPSs), effectively anchoring the LiPSs and suppressing the shuttling effect. When assembled into an S/CNT||BPUSPE||Li whole cell, the system delivers outstanding cycling stability, maintaining a specific capacity of 775.1 mAh g −1 after 60 cycles at 0.1C. Further analysis reveals the formation of a stable solid electrolyte interphase (SEI) rich in LiF and Li₃N, which helps mitigate side reactions and facilitates lithium-ion transport, thereby enhancing overall cell performance. This work offers a feasible and effective strategy for developing high-performance ASSLSBs. • A cross-linked BPUSPE was prepared via the reaction of polyethylene glycol diisocyanate with boroxine. • The dynamic boroxine structures and hydrogen bonds in BPUSPE endow the electrolyte with excellent self-healing capability. • BPUSPE enables better anchoring of lithium polysulfides, thereby suppressing the shuttle effect of polysulfides. • BPUSPE with a boroxine structure exhibits superior electrochemical performance and higher specific capacity.
Jin et al. (Fri,) studied this question.