Benzenediacrylates as organic battery electrode materials: Na versus Li

Abstract

This paper discusses investigations of a novel Na-based organic battery electrode material, disodium benzenediacrylate (Na₂BDA) in comparison with its Li-ion homologue. Li₂BDA has previously shown promising battery properties, such as stable cycling and good capacity retention. Na₂BDA and Li₂BDA are here successfully synthesized and characterized, and investigated as anode materials in prototype Na- and Li-ion battery cells. Moreover, different electrolytes are screened for the Na-battery material, and a useful operating voltage window is explored. Na₂BDA is shown to possess a higher initial coulombic efficiency (91%) than the Li-homologue, which is uncommon for sodiated organic electrode materials. The Na-compound shows an initial capacity of 177.7 mA h g⁻¹, which however decreases to ca. 50 mA h g⁻¹ after 20–100 cycles depending on the cycling rate; a significantly lower capacity retention then that observed for Li₂BDA. The capacity loss can primarily be explained by a decomposition mechanism of the Na₂BDA compound.