Phosphotungstic acid decorated free-standing electrode accelerates polysulfides conversion for high-performance flexible LiS batteries

Lithium‑sulfur batteries (LSBs) with high energy density (2600 Wh kg −1 ) have emerged as prominent candidates among current energy storage systems. However, their progress is hindered by serious shuttle effects, sluggish redox reaction kinetics, and volume expansion. Recently, flexible cellulose materials have shown promising results in inhibiting shuttles and mitigating volume expansion. Nevertheless, a significant gap exists between the practical delivered capacity and the theoretical capacity due to slow sulfur species conversion kinetics. Herein, H 3 PW 12 O 40 (PW 12 ) serves as a bidirectional electrocatalyst anchored on the flexible cellulose substrate, to enhance the conversion behavior of sulfur species and prevent the accumulation and deactivation of active sulfur. Additionally, cellulose acts as a self-supporting host, mitigating shuttling effects and slowing volume expansion, which improving the utilization rate of active substances. As a result, the LSBs assembled with synthetic cathodes (S/PW 12 &PDA@CL) delivered a high initial capacity of 1491 mAh g −1 at 0.1C, and a low-capacity attenuation of only 0.16 % per cycle after 300 cycles at 1.0C. Moreover, even at a high sulfur loading of 2.5 mg cm −2 , S/PW 12 &PDA@CL could still possess a high initial-discharge specific capacity of 1080.6 mAh g −1 at 1.0C and achieved >200 stable cycles.