The elaborate design of powerful Li-S binders with extended-functions like polysulfides adsorption/catalysis and Li+ hopping/transferring in addition to robust adhesion-property has remained a challenge. Here, an in situ cathode-interweaving strategy based on metalloporphyrin based covalent-bonding organic polymer (M-COP, M = Mn, Ni, and Zn) binders is reported for the first time. Thus-produced functional binders possess excellent mechanical-strengths, polysulfides adsorption/catalysis, and Li+ hopping/transferring ability. Specifically, the modulus of Mn-COP can reach up to ≈54.60 GPa (≈40 times higher than poly(vinylidene fluoride)) and the relative cell delivers a high initial-capacity (1027 mAh g-1 , 1 C and 913 mAh g-1 , 2 C), and excellent cycling-stability for >1000 cycles even at 4 C. The utilization-rate of sulfur can reach up to 81.8% and the electrodes based on these powerful binders can be easily scale-up fabricated (≈20 cm in a batch-experiment). Noteworthy, Mn-COP based cell delivers excellent capacities at a high sulfur-loading (8.6 mg cm-2 ) and low E/S ratio (5.8 µL mg-1 ). In addition, theoretical calculations reveal the vital roles of metalloporphyrin and thiourea-groups in enhancing the battery-performance.
Keywords: Li-S cathode; in situ interweaving strategy; lithium polysulfides; metalloporphyrin; polymer binder.
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