Magnesium terephthalate as an organic anode material for sodium ion batteries

Abstract

In this study, the electrochemical properties of magnesium terephthalate with hydration water (MgC8H4O4•2H2O) as an anode material for sodium ion batteries were investigated for the first time. MgC8H4O4• 2H2O was synthesized via a facile neutralization method using terephthalic acid (C8H6O4) and magnesium hydroxide (Mg(OH)2) as precursors. Good cycle performance was obtained as 114 mAh•g-1 was found for the second cycle and 95 mAh•g-1 was obtained after 50 cycles at a current rate of 0.5C (1C=300 mA•g-1), giving a capacity retention of 84%. At a current rate of 2C, it presents a discharge capacity of 90 mAh•g-1. After heating under a nitrogen atmosphere at 400 ℃, anhydrous magnesium terephthalate (MgC8H4O4) was obtained. The effect of hydration water on the crystal structure, morphology, and electrochemical properties was investigated. The results indicate that the specific discharge capacity, rate capacity, and cyclic performance of MgC8H4O4• 2H2O are better than those of MgC8H4O4.