A homemade self-healing material utilized as multi-functional binder for long-lifespan lithium–sulfur batteries
This study reports a supramolecular self-healing material as a multi-functional binder for lithium–sulfur batteries. The spontaneously damage repair ability of such a binder can be applied to overcome the short cycle-life issue of lithium–sulfur batteries under low current density with deep galvanostatic cycling. Diamines and polybasic acids are used to synthesize the supramolecular self-healing material. 10 wt% amine groups in this designed material provide a large amount of chemical adsorption sites for polysulfides which can effectively inhibit the shuttling of polysulfides and maintain the content of sulfur species in cathode. This N-rich binder is mixed with the sulfur during preparation, which can improve the effective contacting surface of N function groups and sulfur locally. The cells with pure self-healing material binder achieve an initial capacity of 918 mAh g−1, and maintain a reversible capacity of 469 mAh g−1 after 200 cycles at 0.1C, twice higher than the retention capacity of cells with polyvinylidene fluoride binder. After optimization, the cells with a hybrid binder of self-healing material and polyvinylidene fluoride (weight ratio of 1:1) with a sulfur loading of 2.65 mg cm−2 achieve an initial capacity of 993 mAh g−1, and remain a reversible capacity of 571 mAh g−1 with a capacity fade of 0.2% per cycle after 200 cycles at 0.1C.
This work was supported by the National Natural Science Foundation for Excellent Young Scholars (Grant No. 51722703), National Natural Science Foundation of China (Grant No. 51572147) and Beijing Natural Science Foundation (Grant No. 3162017).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.