In the past, sodium alanate, NaAlH_(4), 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. NaAlH_(4) has recently been considered for Li-ion storage as a conversion-type anode in Li-ion batteries. Here, NaAlH_(4) nanoconfined in carbon scaffolds as an anode material for Li-ion batteries is reported for the first time. Nanoconfined NaAlH_(4) was prepared by melt infiltration into mesoporous carbon scaffolds. In the first cycle, the electrochemical reversibility of nanoconfined NaAlH_(4) was improved from around 30 to 70% compared to that of nonconfined NaAlH_(4). Cyclic voltammetry revealed that nanoconfinement alters the conversion pathway, and operando powder X-ray diffraction showed that the conversion from NaAlH_(4) into Na_(3)AlH_(6) is favored over the formation of LiNa_(2)AlH_(6). The electrochemical reactivity of the carbon scaffolds has also been investigated to study their contribution to the overall capacity of the electrodes.
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