Bifunctional separator with nest-like MnOOH network via facile in situ synthesis for highly stable and “Li-dendrite free” lithium-sulfur batteries

• Published in: Materials today energy 2024-03, Vol.40, p.101489, Article 101489
• Main Authors: Sun, Linghao, Li, Hehong, Zhou, Junli, Wu, Zhonghui, Liao, Ruanming, Peng, Zhihong, Yu, Lin, Zhang, Qianyu
• Format: Article
• Language: English
• Subjects: Dendrite free; High stability; Lithium polysulfides; Li–S battery; Modified separator
• ISSN: 2468-6069; 2468-6069
• DOI: 10.1016/j.mtener.2024.101489

The slow redox kinetics in the sulfur cathode and lithium (Li)-dendrite growth on the lithium anode leads to significant capacity degradation and serious safety incidents for lithium-sulfur (Li–S) batteries. Herein, a bifunctional polypropylene separator with nest-like MnOOH network synergistic carbon layer (MnOOH/C/PP) via facile in situ synthesis method was designed as an effective host for both sulfur cathode and lithium anode. A series of electrochemical tests and non–in situ scanning electron microscope characterization confirmed that the as-prepared MnOOH/C layer has good physical/chemical adsorption and catalytic activity of polysulfides. Furthermore, the Li||Li symmetric batteries exhibited inhibited dendrite growth even after undergoing cycling for more than 2200 h at 1 mA/cm2. Consequently, the Li–S battery based on a functional MnOOH/C/PP separator shows high discharge capacity (1358 mAh/g at 0.1 C), good rate capability (755 mAh/g at 3 C) and stable cyclability (0.049 % decay per cycle over 700 cycles). Particularly, an areal capacity can reach 3.55 mAh/cm2 even at a high sulfur loading of 7.02 mg/cm2 and a high-capacity retention rate of 90.2 % remained over 200 cycles, demonstrating the viability of this simple and efficient strategy for creating highly stable and safe Li–S batteries. [Display omitted] •Nest-like MnOOH network synergistic carbon layer modified separator was designed.•The modified MnOOH/C/PP has strong anchoring and fast conversion of polysulfides.•The nest-like structure could buffer Li+ flux and achieve homogeneous Li nucleation.•Cells with MnOOH/C/PP separators exhibit outstanding rate and cycling performance.