Binder-free and high-loading sulfurized polyacrylonitrile cathode for lithium/sulfur batteries

Mussel and Cobweb Inspired High Areal Capacity SPAN Electrode

Lithium-sulfur batteries (LSBs) with superior energy density are among the most promising candidates for next-generation energy storage techniques. Sulfurized polyacrylonitrile (SPAN) exhibits competitive advantages in terms of cycle stability, rate performance as well as cost. However, the preparation of high-loading SPAN electrodes is still challenging. Herein, inspired by mussel and cobweb, a high-loading SPAN electrode is enabled by the combination of polydopamine (PDA) coating and a bimodal distributed single-wall carbon nanotubes (SWCNT) slurry dispersed in polyvinylpyrrolidone (PVP), their synergistic effect not only constructs effective electron percolating networks within the electrode but also make high active material (AM) ratio possible. High areal capacity PDA@SPAN electrode (18.40 mAh cm-2 in the initial cycle) with negligible specific capacity attenuation as the mass loading increasement is realized through the facile slurry casting process. The dynamic N─H…O hydrogen bond is formed between PDA and PVP and the electrode integrity during charge/discharge is greatly strengthened. The battery with an areal AM loading of 7.16 mg cm-2 (5.16 mAh cm-2) retains 92.0% of capacity in 80 cycles and 87.18% in 160 cycles, and it also shows stable cycle performances even with a high loading of 19.79 mg cm-2 and lean electrolyte (3.28 µL mg-1).