Chemical and spatial dual-confinement engineering for stable Na-S batteries with approximately 100% capacity retention.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37983506.
- Also identified by DOI 10.1073/pnas.2314408120 and PMC identifier 10691245.
- Licence recorded as CC BY-NC-ND.
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Abstract
Sodium-sulfur (Na-S) batteries are attracting intensive attention due to the merits like high energy and low cost, while the poor stability of sulfur cathode limits the further development. Here, we report a chemical and spatial dual-confinement approach to improve the stability of Na-S batteries. It refers to covalently bond sulfur to carbon at forms of C-S/N-C=S bonds with high strength for locking sulfur. Meanwhile, sulfur is examined to be S<sub>1</sub>-S<sub>2</sub> small species produced by thermally cutting S<sub>8</sub> large molecules followed by sealing in the confined pores of carbon materials. Hence, the sulfur cathode achieves a good stability of maintaining a high-capacity retention of 97.64% after 1000 cycles. Experimental and theoretical results show that Na<sup>+</sup> is hosted via a coordination structure (N···Na···S) without breaking the C-S bond, thus impeding the formation and dissolution of sodium polysulfide to ensure a good cycling stability. This work provides a promising method for addressing the S-triggered stability problem of Na-S batteries and other S-based batteries.