A robust aqueous-processable polymer binder for long-life, high-performance lithium sulfur battery

The development of lithium sulfur batteries (LSBs) has significantly suffered from the shuttle of lithium polysulfides (LiPS) and drastic volume change of the active materials during cycling processes. The eco-friendly manufacturing of electrodes based on aqueous slurries is highly desirable for practical applications. To address these challenging issues, a novel aqueous-processable polymer, chitosan sulfate ethylamide glycinamide (CSEG), has been developed as the binder for sulfur cathode. The dual-amide structures endow the CSEG with superior LiPS-trapping capability to impede the diffusion and shuttle of LiPS in electrolyte. The CSEG-based sulfur cathodes demonstrate remarkable cycling performances at 1 C for 700 cycles and 6 C for 450 cycles, with only 0.049%, 0.0895% capacity fading per cycle, respectively. More importantly, the cathode achieves excellent rate performance with a capacity of 194.4 mAh g-1 at an ultrahigh current density of 40.26 mA cm-2 (20 C), which takes only 21 s for one charge or discharge process. The electrochemical performance of the novel CSEG binder, as demonstrated in this work, is superior to all previously reported aqueous-processable binders for sulfur cathode. Such a breakthrough will greatly improve the development of eco-friendly sulfur cathode, paving new ways for the practical application of next-generation LSBs.