Nanoconfined NaAlH4 Conversion Electrodes for Li Batteries

Priscilla Huen; Filippo Peru; Georgia Charalambopoulou; Theodore A Steriotis; Torben R Jensen; Dorthe B Ravnsbæk

doi:10.1021/acsomega.7b00143

Nanoconfined NaAlH₄ Conversion Electrodes for Li Batteries

ACS Omega. 2017 May 10;2(5):1956-1967. doi: 10.1021/acsomega.7b00143. eCollection 2017 May 31.

Authors

Priscilla Huen¹, Filippo Peru², Georgia Charalambopoulou², Theodore A Steriotis², Torben R Jensen¹, Dorthe B Ravnsbæk³

Affiliations

¹ Center for Materials Crystallography, Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
² National Center for Scientific Research "Demokritos", 15310 Agia Paraskevi Attikis, Greece.
³ Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.

Abstract

In the past, sodium alanate, NaAlH₄, has been widely investigated for its capability to store hydrogen, and its potential for improving storage properties through nanoconfinement in carbon scaffolds has been extensively studied. NaAlH₄ has recently been considered for Li-ion storage as a conversion-type anode in Li-ion batteries. Here, NaAlH₄ nanoconfined in carbon scaffolds as an anode material for Li-ion batteries is reported for the first time. Nanoconfined NaAlH₄ was prepared by melt infiltration into mesoporous carbon scaffolds. In the first cycle, the electrochemical reversibility of nanoconfined NaAlH₄ was improved from around 30 to 70% compared to that of nonconfined NaAlH₄. Cyclic voltammetry revealed that nanoconfinement alters the conversion pathway, and operando powder X-ray diffraction showed that the conversion from NaAlH₄ into Na₃AlH₆ is favored over the formation of LiNa₂AlH₆. The electrochemical reactivity of the carbon scaffolds has also been investigated to study their contribution to the overall capacity of the electrodes.