Highly reversible lithium storage in cobalt 2,5-dioxido-1,4-benzenedicarboxylate metal-organic frameworks boosted by pseudocapacitance.

Author(s) Liao, Y.; Li, C.; Lou, X.; Wang, P.; Yang, Q.; Shen, M.; Hu, B.
Journal J Colloid Interface Sci
Date Published 2017 Nov 15
Abstract

Exploiting novel metal-organic frameworks (MOFs) as electrode materials with superior rate capabilities and understanding their electrochemical behaviour in detail are crucial for boosting the application of MOFs in the field of energy storage. Herein, we prepared Co2(DOBDC) (DOBDC=2,5-dioxido-1,4-benzenedicarboxylate) via a hydrothermal method and explored its electrochemical performance as an anode material for lithium-ion batteries. The as-prepared Co2(DOBDC) MOF exhibits a reversible capacity of 526.1mAhg(-1) after 200 charge/discharge cycles at a current density of 500mAg(-1) and also demonstrates an impressive rate capability, with a high capacity of 408.2mAhg(-1) at a high current density of 2Ag(-1). Furthermore, synchrotron-based soft X-ray absorption spectroscopy (sXAS) and electron paramagnetic resonance (EPR) spectroscopy have been applied to investigate the spin state of cobalt in the electrodes at different states of charge. Our results suggest that localized electrons in high-spin (S=3/2) Co(2+) in pristine Co2(DOBDC) are gradually delocalized after discharging. It was also found that the high rate capability of Co2(DOBDC) is mainly ascribed to an ultrafast ion intercalation pseudocapacitance process, which results from its unique microporous architecture and adequate specific surface that offers sufficient electrode/electrolyte contact and benefits fast Li(+) ion diffusion.

DOI 10.1016/j.jcis.2017.07.063
ISSN 1095-7103
Citation Liao Y, Li C, Lou X, Wang P, Yang Q, Shen M, et al. Highly reversible lithium storage in cobalt 2,5-dioxido-1,4-benzenedicarboxylate metal-organic frameworks boosted by pseudocapacitance. J Colloid Interface Sci. 2017;506:365-372.

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