Among 'beyond lithium ion' energy storage, lithium sulfur (LiÀ S) batteries are one of the most promising technologies, as a result of the potential for high theoretical energy capacity at low cost. A key obstacle in exploiting the vast potential of LiÀ S batteries is the formation of soluble polysulfide species. Here, we report sulfurized polypropylene (S/PP-500) synthesized in one-step by reacting polypropylene (PP) with sulfur as a new polysulfide shuttle-free cathode material for LiÀ S batteries. It exhibits a reversible capacity as high as 1000 mAh/g sulfur at 0.1 C and a sulfur loading of up to 68 wt%, which in turn allows for high sulfur loadings up to 47 % in the final cathode. The lowcost starting materials together with the simple synthetic procedure and the good electrochemical performance in combination with a commercially available eslectrolyte make the S/PP-500 a very promising cathode material for Li-S batteries.

Lithium–sulfur (Li–S) batteries are among the most promising candidates for next-generation high-energy-density batteries; however, the polysulfide shuttle represents a major drawback in their application. Here, we report on sulfurized poly­(norbornadiene) (S/pNBD) and its analogue, sulfurized poly­(dicyclopentadiene) (S/pDCPD), two polysulfide shuttle-free and cheap cathode materials with good performance in Li–S battery technology. Both S/pNBD and S/pDCPD can be prepared in a straightforward two-step procedure. Time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy measurements, and cyclic voltammetry indicate that all sulfur in S/pNBD and S/pDCPD is covalently bound to the polymer matrix in the form of C–S x –C units. Li–S cells based on an S/pNBD cathode exhibit a high discharge capacity up to 1050 mA h/g sulfur at 1 C with a good capacity retention of 62 % after 1900 cycles. The structurally similar analogue S/pDCPD shows comparable electrochemical performance, again with excellent capacity retention. The high reversibility and ultra-long cycle life of both, S/pNBD and S/pDCPD, are attributed to the covalent binding of sulfur to the polymer backbone.

Nontoxic, eco-friendly, and high-energy-density sulfurated poly­(propylene) (S/PP-waste) has been prepared in a one-step vulcanization process from recycled poly­(propylene) waste and used as a cathode material in lithium–sulfur (Li–S) batteries. A sulfur loading of up to 50.4 wt % was achieved. In S/PP-waste, the sulfur is covalently bound to the polymer matrix, selectively resulting in a solid phase transition during charge and discharge. Consequently, the polysulfide shuttle can be avoided, which results in satisfactory electrochemical performance with ultralong cycle life and a low capacity decay per cycle of ∼0.018% at 0.5C. S/PP-waste was also explored for the first time as an anode material in LiMn2O4-based Li-ion full cells. Its good electrochemical performance as well as its recycled nature make it a promising energy storage material for the future.