Anion-Regulated Sulfur Conversion in High-Content Carbon Layer Confined Sulfur Cathode Maximizes Voltage and Rate Capability of K-S Batteries.
Adv Mater
; 36(15): e2311127, 2024 Apr.
Article
en En
| MEDLINE
| ID: mdl-38181516
ABSTRACT
Potassium-sulfur (K-S) batteries have attracted attention in large-scale energy storage systems. Small-molecule/covalent sulfur (SMCS) can help to avoid the shuttle effect of polysulfide ions via solid-solid sulfur conversion. However, the content of SMCS is relatively low (≤40%), and solid-solid reactions cause sluggish kinetics and low discharge potentials. Herein, SMCS is confined in turbo carbon layers with a content of ≈74.1 wt% via a C/S co-deposition process. In the K-S battery assembled by using as-fabricated SMCS@C as cathode and KFSI-EC/DEC as an electrolyte, anion-regulated two-plateau solid-state S conversion chemistry and a novel high discharge potential plateau at 2.5-2.0 V with a remarkable reversible capacity of 384 mAh g-1 at 3 A g-1 after 1000 cycles are found. The SMCS@C||K full cell showed energy and power density of 72.8 Wh kg-1 and 873.2 W kg-1, respectively, at 3 A g-1. Mechanism studies reveal that the enlarged carbon layer space enables the diffusion of K+-FSI- ion pairs, and the coulombic attraction between them accelerates their diffusion in SMCS@C. In addition, FSI- regulates sulfur conversion in situ inside the carbon layers along a two-plateau solid-state reaction pathway, which lowers the free energy and weakens the SâS bond of intermediates, leading to faster and more efficient S conversion.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Adv Mater
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
China