Cracking-Controlled Slurry Coating of Mosaic Electrode for Flexible and High-Performance Lithium–Sulfur Battery

The realization of high-performance thick S cathodes is a critical step to achieve high energy density lithium–sulfur (Li–S) batteries. However, it normally requires a complicated and time-consuming fabrication processes to obtain high-performance S cathodes with high mass loading. On the other hand, thick S cathodes fabricated with high-speed slurry coating method show poor flexibility, capacity, and cycle life due to unpredictable electrode cracking. Herein, an industrial-speed cracking-controlled slurry coating method to generate mosaic-like cracks in the S cathode is developed, which provides vertical channels to facilitate the rapid diffusion of electrolyte, adequate space to accommodate the volume expansion during cycling, and strain-releasing structure to achieve high flexibility. With this simple method, thick Mosaic-S cathodes (9 mAh cm⁻²) provide outstanding energy density, long cycle life, and outstanding flexibility under dynamic bending. This work paves the way for scalable fabrication of high-performance S cathodes in the near future.