Revitalizing Iron Redox by Anion-Insertion-Assisted Ferro- and Ferri-Hydroxides Conversion at Low Alkalinity.
Fenghua GuoSathya Narayanan JagadeesanRanga Teja PidathalaSaeWon KimXiaoqiang ShanN Aaron DeskinsA M Milinda AbeykoonGihan KwonDaniel OldsBadri NarayananXiaowei TengPublished in: Journal of the American Chemical Society (2022)
Iron hydroxides are desirable alkaline battery electrodes for low cost and environmental beneficence. However, hydrogen evolution on charging and Fe 3 O 4 formation on discharging cause low storage capacity and poor cycling life. We report that green rust (GR) (Fe 2+ 4 Fe 3+ 2 (HO - ) 12 SO 4 ), formed via sulfate insertion, promotes Fe(OH) 2 /FeOOH conversion and shows a discharge capacity of ∼211 mAh g -1 in half-cells and Coulombic efficiency of 93% after 300 cycles in full-cells. Theoretical calculations show that Fe(OH) 2 /FeOOH conversion is facilitated by intercalated sulfate anions. Classical molecular dynamics simulations reveal that electrolyte alkalinity strongly impacts the energetics of sulfate solvation, and low alkalinity ensures fast transport of sulfate ions. Anion-insertion-assisted Fe(OH) 2 /FeOOH conversion, also achieved with Cl - ion, paves a pathway toward efficient utilization of Fe-based electrodes for sustainable applications.
Keyphrases
- molecular dynamics simulations
- ionic liquid
- aqueous solution
- induced apoptosis
- metal organic framework
- low cost
- cell cycle arrest
- molecular docking
- visible light
- dna methylation
- endoplasmic reticulum stress
- gene expression
- high intensity
- carbon nanotubes
- cell proliferation
- risk assessment
- oxidative stress
- density functional theory
- human health