A carboxylate group-based organic anode for sustainable and stable sodium ion batteries

The carboxylate group-based organic electrode materials are promising anodes for rechargeable sodium ion batteries (SIBs) due to the low cost, abundance, environmental benignity and high sustainability of organic materials. Here, we compare the electrochemical performance of three carboxylate group-based organic electrode materials in SIBs, and identify that the two carboxylate groups in the para position of the benzene ring are electrochemical active centers to reversibly react with Na-ions and electrons. The carboxylate group-based anode, trisodium 1,2,4-benzenetricarboxylate (TBC), exhibits exceptional electrochemical performance in SIBs, in terms of high specific capacity (195 mAh g−1) and long cycle life (600 cycles). The third carboxylate group in TBC enhances the sodiation/de-sodiation potentials, and reduces its solubility in the electrolyte, resulting in a highly stable organic anode. The low cost, high sustainability, high capacity and high cyclic stability of TBC render it a promising anode material for SIBs.